| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Shared application/kernel submission and completion ring pairs, for |
| * supporting fast/efficient IO. |
| * |
| * A note on the read/write ordering memory barriers that are matched between |
| * the application and kernel side. |
| * |
| * After the application reads the CQ ring tail, it must use an |
| * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses |
| * before writing the tail (using smp_load_acquire to read the tail will |
| * do). It also needs a smp_mb() before updating CQ head (ordering the |
| * entry load(s) with the head store), pairing with an implicit barrier |
| * through a control-dependency in io_get_cqring (smp_store_release to |
| * store head will do). Failure to do so could lead to reading invalid |
| * CQ entries. |
| * |
| * Likewise, the application must use an appropriate smp_wmb() before |
| * writing the SQ tail (ordering SQ entry stores with the tail store), |
| * which pairs with smp_load_acquire in io_get_sqring (smp_store_release |
| * to store the tail will do). And it needs a barrier ordering the SQ |
| * head load before writing new SQ entries (smp_load_acquire to read |
| * head will do). |
| * |
| * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application |
| * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after* |
| * updating the SQ tail; a full memory barrier smp_mb() is needed |
| * between. |
| * |
| * Also see the examples in the liburing library: |
| * |
| * git://git.kernel.dk/liburing |
| * |
| * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens |
| * from data shared between the kernel and application. This is done both |
| * for ordering purposes, but also to ensure that once a value is loaded from |
| * data that the application could potentially modify, it remains stable. |
| * |
| * Copyright (C) 2018-2019 Jens Axboe |
| * Copyright (c) 2018-2019 Christoph Hellwig |
| */ |
| #include <linux/kernel.h> |
| #include <linux/init.h> |
| #include <linux/errno.h> |
| #include <linux/syscalls.h> |
| #include <linux/compat.h> |
| #include <linux/refcount.h> |
| #include <linux/uio.h> |
| |
| #include <linux/sched/signal.h> |
| #include <linux/fs.h> |
| #include <linux/file.h> |
| #include <linux/fdtable.h> |
| #include <linux/mm.h> |
| #include <linux/mman.h> |
| #include <linux/mmu_context.h> |
| #include <linux/percpu.h> |
| #include <linux/slab.h> |
| #include <linux/kthread.h> |
| #include <linux/blkdev.h> |
| #include <linux/bvec.h> |
| #include <linux/net.h> |
| #include <net/sock.h> |
| #include <net/af_unix.h> |
| #include <net/scm.h> |
| #include <linux/anon_inodes.h> |
| #include <linux/sched/mm.h> |
| #include <linux/uaccess.h> |
| #include <linux/nospec.h> |
| #include <linux/sizes.h> |
| #include <linux/hugetlb.h> |
| #include <linux/highmem.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/io_uring.h> |
| |
| #include <uapi/linux/io_uring.h> |
| |
| #include "internal.h" |
| #include "io-wq.h" |
| |
| #define IORING_MAX_ENTRIES 32768 |
| #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES) |
| |
| /* |
| * Shift of 9 is 512 entries, or exactly one page on 64-bit archs |
| */ |
| #define IORING_FILE_TABLE_SHIFT 9 |
| #define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT) |
| #define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1) |
| #define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE) |
| |
| struct io_uring { |
| u32 head ____cacheline_aligned_in_smp; |
| u32 tail ____cacheline_aligned_in_smp; |
| }; |
| |
| /* |
| * This data is shared with the application through the mmap at offsets |
| * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING. |
| * |
| * The offsets to the member fields are published through struct |
| * io_sqring_offsets when calling io_uring_setup. |
| */ |
| struct io_rings { |
| /* |
| * Head and tail offsets into the ring; the offsets need to be |
| * masked to get valid indices. |
| * |
| * The kernel controls head of the sq ring and the tail of the cq ring, |
| * and the application controls tail of the sq ring and the head of the |
| * cq ring. |
| */ |
| struct io_uring sq, cq; |
| /* |
| * Bitmasks to apply to head and tail offsets (constant, equals |
| * ring_entries - 1) |
| */ |
| u32 sq_ring_mask, cq_ring_mask; |
| /* Ring sizes (constant, power of 2) */ |
| u32 sq_ring_entries, cq_ring_entries; |
| /* |
| * Number of invalid entries dropped by the kernel due to |
| * invalid index stored in array |
| * |
| * Written by the kernel, shouldn't be modified by the |
| * application (i.e. get number of "new events" by comparing to |
| * cached value). |
| * |
| * After a new SQ head value was read by the application this |
| * counter includes all submissions that were dropped reaching |
| * the new SQ head (and possibly more). |
| */ |
| u32 sq_dropped; |
| /* |
| * Runtime flags |
| * |
| * Written by the kernel, shouldn't be modified by the |
| * application. |
| * |
| * The application needs a full memory barrier before checking |
| * for IORING_SQ_NEED_WAKEUP after updating the sq tail. |
| */ |
| u32 sq_flags; |
| /* |
| * Number of completion events lost because the queue was full; |
| * this should be avoided by the application by making sure |
| * there are not more requests pending than there is space in |
| * the completion queue. |
| * |
| * Written by the kernel, shouldn't be modified by the |
| * application (i.e. get number of "new events" by comparing to |
| * cached value). |
| * |
| * As completion events come in out of order this counter is not |
| * ordered with any other data. |
| */ |
| u32 cq_overflow; |
| /* |
| * Ring buffer of completion events. |
| * |
| * The kernel writes completion events fresh every time they are |
| * produced, so the application is allowed to modify pending |
| * entries. |
| */ |
| struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp; |
| }; |
| |
| struct io_mapped_ubuf { |
| u64 ubuf; |
| size_t len; |
| struct bio_vec *bvec; |
| unsigned int nr_bvecs; |
| }; |
| |
| struct fixed_file_table { |
| struct file **files; |
| }; |
| |
| struct io_ring_ctx { |
| struct { |
| struct percpu_ref refs; |
| } ____cacheline_aligned_in_smp; |
| |
| struct { |
| unsigned int flags; |
| bool compat; |
| bool account_mem; |
| bool cq_overflow_flushed; |
| bool drain_next; |
| |
| /* |
| * Ring buffer of indices into array of io_uring_sqe, which is |
| * mmapped by the application using the IORING_OFF_SQES offset. |
| * |
| * This indirection could e.g. be used to assign fixed |
| * io_uring_sqe entries to operations and only submit them to |
| * the queue when needed. |
| * |
| * The kernel modifies neither the indices array nor the entries |
| * array. |
| */ |
| u32 *sq_array; |
| unsigned cached_sq_head; |
| unsigned sq_entries; |
| unsigned sq_mask; |
| unsigned sq_thread_idle; |
| unsigned cached_sq_dropped; |
| atomic_t cached_cq_overflow; |
| struct io_uring_sqe *sq_sqes; |
| |
| struct list_head defer_list; |
| struct list_head timeout_list; |
| struct list_head cq_overflow_list; |
| |
| wait_queue_head_t inflight_wait; |
| } ____cacheline_aligned_in_smp; |
| |
| struct io_rings *rings; |
| |
| /* IO offload */ |
| struct io_wq *io_wq; |
| struct task_struct *sqo_thread; /* if using sq thread polling */ |
| struct mm_struct *sqo_mm; |
| wait_queue_head_t sqo_wait; |
| |
| /* |
| * If used, fixed file set. Writers must ensure that ->refs is dead, |
| * readers must ensure that ->refs is alive as long as the file* is |
| * used. Only updated through io_uring_register(2). |
| */ |
| struct fixed_file_table *file_table; |
| unsigned nr_user_files; |
| |
| /* if used, fixed mapped user buffers */ |
| unsigned nr_user_bufs; |
| struct io_mapped_ubuf *user_bufs; |
| |
| struct user_struct *user; |
| |
| const struct cred *creds; |
| |
| /* 0 is for ctx quiesce/reinit/free, 1 is for sqo_thread started */ |
| struct completion *completions; |
| |
| /* if all else fails... */ |
| struct io_kiocb *fallback_req; |
| |
| #if defined(CONFIG_UNIX) |
| struct socket *ring_sock; |
| #endif |
| |
| struct { |
| unsigned cached_cq_tail; |
| unsigned cq_entries; |
| unsigned cq_mask; |
| atomic_t cq_timeouts; |
| struct wait_queue_head cq_wait; |
| struct fasync_struct *cq_fasync; |
| struct eventfd_ctx *cq_ev_fd; |
| } ____cacheline_aligned_in_smp; |
| |
| struct { |
| struct mutex uring_lock; |
| wait_queue_head_t wait; |
| } ____cacheline_aligned_in_smp; |
| |
| struct { |
| spinlock_t completion_lock; |
| bool poll_multi_file; |
| /* |
| * ->poll_list is protected by the ctx->uring_lock for |
| * io_uring instances that don't use IORING_SETUP_SQPOLL. |
| * For SQPOLL, only the single threaded io_sq_thread() will |
| * manipulate the list, hence no extra locking is needed there. |
| */ |
| struct list_head poll_list; |
| struct hlist_head *cancel_hash; |
| unsigned cancel_hash_bits; |
| |
| spinlock_t inflight_lock; |
| struct list_head inflight_list; |
| } ____cacheline_aligned_in_smp; |
| }; |
| |
| /* |
| * First field must be the file pointer in all the |
| * iocb unions! See also 'struct kiocb' in <linux/fs.h> |
| */ |
| struct io_poll_iocb { |
| struct file *file; |
| struct wait_queue_head *head; |
| __poll_t events; |
| bool done; |
| bool canceled; |
| struct wait_queue_entry wait; |
| }; |
| |
| struct io_timeout_data { |
| struct io_kiocb *req; |
| struct hrtimer timer; |
| struct timespec64 ts; |
| enum hrtimer_mode mode; |
| u32 seq_offset; |
| }; |
| |
| struct io_async_connect { |
| struct sockaddr_storage address; |
| }; |
| |
| struct io_async_msghdr { |
| struct iovec fast_iov[UIO_FASTIOV]; |
| struct iovec *iov; |
| struct sockaddr __user *uaddr; |
| struct msghdr msg; |
| }; |
| |
| struct io_async_rw { |
| struct iovec fast_iov[UIO_FASTIOV]; |
| struct iovec *iov; |
| ssize_t nr_segs; |
| ssize_t size; |
| }; |
| |
| struct io_async_ctx { |
| struct io_uring_sqe sqe; |
| union { |
| struct io_async_rw rw; |
| struct io_async_msghdr msg; |
| struct io_async_connect connect; |
| struct io_timeout_data timeout; |
| }; |
| }; |
| |
| /* |
| * NOTE! Each of the iocb union members has the file pointer |
| * as the first entry in their struct definition. So you can |
| * access the file pointer through any of the sub-structs, |
| * or directly as just 'ki_filp' in this struct. |
| */ |
| struct io_kiocb { |
| union { |
| struct file *file; |
| struct kiocb rw; |
| struct io_poll_iocb poll; |
| }; |
| |
| const struct io_uring_sqe *sqe; |
| struct io_async_ctx *io; |
| struct file *ring_file; |
| int ring_fd; |
| bool has_user; |
| bool in_async; |
| bool needs_fixed_file; |
| |
| struct io_ring_ctx *ctx; |
| union { |
| struct list_head list; |
| struct hlist_node hash_node; |
| }; |
| struct list_head link_list; |
| unsigned int flags; |
| refcount_t refs; |
| #define REQ_F_NOWAIT 1 /* must not punt to workers */ |
| #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ |
| #define REQ_F_FIXED_FILE 4 /* ctx owns file */ |
| #define REQ_F_LINK_NEXT 8 /* already grabbed next link */ |
| #define REQ_F_IO_DRAIN 16 /* drain existing IO first */ |
| #define REQ_F_IO_DRAINED 32 /* drain done */ |
| #define REQ_F_LINK 64 /* linked sqes */ |
| #define REQ_F_LINK_TIMEOUT 128 /* has linked timeout */ |
| #define REQ_F_FAIL_LINK 256 /* fail rest of links */ |
| #define REQ_F_DRAIN_LINK 512 /* link should be fully drained */ |
| #define REQ_F_TIMEOUT 1024 /* timeout request */ |
| #define REQ_F_ISREG 2048 /* regular file */ |
| #define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */ |
| #define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */ |
| #define REQ_F_INFLIGHT 16384 /* on inflight list */ |
| #define REQ_F_COMP_LOCKED 32768 /* completion under lock */ |
| #define REQ_F_HARDLINK 65536 /* doesn't sever on completion < 0 */ |
| u64 user_data; |
| u32 result; |
| u32 sequence; |
| |
| struct list_head inflight_entry; |
| |
| struct io_wq_work work; |
| }; |
| |
| #define IO_PLUG_THRESHOLD 2 |
| #define IO_IOPOLL_BATCH 8 |
| |
| struct io_submit_state { |
| struct blk_plug plug; |
| |
| /* |
| * io_kiocb alloc cache |
| */ |
| void *reqs[IO_IOPOLL_BATCH]; |
| unsigned int free_reqs; |
| unsigned int cur_req; |
| |
| /* |
| * File reference cache |
| */ |
| struct file *file; |
| unsigned int fd; |
| unsigned int has_refs; |
| unsigned int used_refs; |
| unsigned int ios_left; |
| }; |
| |
| static void io_wq_submit_work(struct io_wq_work **workptr); |
| static void io_cqring_fill_event(struct io_kiocb *req, long res); |
| static void __io_free_req(struct io_kiocb *req); |
| static void io_put_req(struct io_kiocb *req); |
| static void io_double_put_req(struct io_kiocb *req); |
| static void __io_double_put_req(struct io_kiocb *req); |
| static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req); |
| static void io_queue_linked_timeout(struct io_kiocb *req); |
| |
| static struct kmem_cache *req_cachep; |
| |
| static const struct file_operations io_uring_fops; |
| |
| struct sock *io_uring_get_socket(struct file *file) |
| { |
| #if defined(CONFIG_UNIX) |
| if (file->f_op == &io_uring_fops) { |
| struct io_ring_ctx *ctx = file->private_data; |
| |
| return ctx->ring_sock->sk; |
| } |
| #endif |
| return NULL; |
| } |
| EXPORT_SYMBOL(io_uring_get_socket); |
| |
| static void io_ring_ctx_ref_free(struct percpu_ref *ref) |
| { |
| struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); |
| |
| complete(&ctx->completions[0]); |
| } |
| |
| static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) |
| { |
| struct io_ring_ctx *ctx; |
| int hash_bits; |
| |
| ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); |
| if (!ctx) |
| return NULL; |
| |
| ctx->fallback_req = kmem_cache_alloc(req_cachep, GFP_KERNEL); |
| if (!ctx->fallback_req) |
| goto err; |
| |
| ctx->completions = kmalloc(2 * sizeof(struct completion), GFP_KERNEL); |
| if (!ctx->completions) |
| goto err; |
| |
| /* |
| * Use 5 bits less than the max cq entries, that should give us around |
| * 32 entries per hash list if totally full and uniformly spread. |
| */ |
| hash_bits = ilog2(p->cq_entries); |
| hash_bits -= 5; |
| if (hash_bits <= 0) |
| hash_bits = 1; |
| ctx->cancel_hash_bits = hash_bits; |
| ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head), |
| GFP_KERNEL); |
| if (!ctx->cancel_hash) |
| goto err; |
| __hash_init(ctx->cancel_hash, 1U << hash_bits); |
| |
| if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, |
| PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) |
| goto err; |
| |
| ctx->flags = p->flags; |
| init_waitqueue_head(&ctx->cq_wait); |
| INIT_LIST_HEAD(&ctx->cq_overflow_list); |
| init_completion(&ctx->completions[0]); |
| init_completion(&ctx->completions[1]); |
| mutex_init(&ctx->uring_lock); |
| init_waitqueue_head(&ctx->wait); |
| spin_lock_init(&ctx->completion_lock); |
| INIT_LIST_HEAD(&ctx->poll_list); |
| INIT_LIST_HEAD(&ctx->defer_list); |
| INIT_LIST_HEAD(&ctx->timeout_list); |
| init_waitqueue_head(&ctx->inflight_wait); |
| spin_lock_init(&ctx->inflight_lock); |
| INIT_LIST_HEAD(&ctx->inflight_list); |
| return ctx; |
| err: |
| if (ctx->fallback_req) |
| kmem_cache_free(req_cachep, ctx->fallback_req); |
| kfree(ctx->completions); |
| kfree(ctx->cancel_hash); |
| kfree(ctx); |
| return NULL; |
| } |
| |
| static inline bool __req_need_defer(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| return req->sequence != ctx->cached_cq_tail + ctx->cached_sq_dropped |
| + atomic_read(&ctx->cached_cq_overflow); |
| } |
| |
| static inline bool req_need_defer(struct io_kiocb *req) |
| { |
| if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) == REQ_F_IO_DRAIN) |
| return __req_need_defer(req); |
| |
| return false; |
| } |
| |
| static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx) |
| { |
| struct io_kiocb *req; |
| |
| req = list_first_entry_or_null(&ctx->defer_list, struct io_kiocb, list); |
| if (req && !req_need_defer(req)) { |
| list_del_init(&req->list); |
| return req; |
| } |
| |
| return NULL; |
| } |
| |
| static struct io_kiocb *io_get_timeout_req(struct io_ring_ctx *ctx) |
| { |
| struct io_kiocb *req; |
| |
| req = list_first_entry_or_null(&ctx->timeout_list, struct io_kiocb, list); |
| if (req) { |
| if (req->flags & REQ_F_TIMEOUT_NOSEQ) |
| return NULL; |
| if (!__req_need_defer(req)) { |
| list_del_init(&req->list); |
| return req; |
| } |
| } |
| |
| return NULL; |
| } |
| |
| static void __io_commit_cqring(struct io_ring_ctx *ctx) |
| { |
| struct io_rings *rings = ctx->rings; |
| |
| if (ctx->cached_cq_tail != READ_ONCE(rings->cq.tail)) { |
| /* order cqe stores with ring update */ |
| smp_store_release(&rings->cq.tail, ctx->cached_cq_tail); |
| |
| if (wq_has_sleeper(&ctx->cq_wait)) { |
| wake_up_interruptible(&ctx->cq_wait); |
| kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); |
| } |
| } |
| } |
| |
| static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe) |
| { |
| u8 opcode = READ_ONCE(sqe->opcode); |
| |
| return !(opcode == IORING_OP_READ_FIXED || |
| opcode == IORING_OP_WRITE_FIXED); |
| } |
| |
| static inline bool io_prep_async_work(struct io_kiocb *req, |
| struct io_kiocb **link) |
| { |
| bool do_hashed = false; |
| |
| if (req->sqe) { |
| switch (req->sqe->opcode) { |
| case IORING_OP_WRITEV: |
| case IORING_OP_WRITE_FIXED: |
| /* only regular files should be hashed for writes */ |
| if (req->flags & REQ_F_ISREG) |
| do_hashed = true; |
| /* fall-through */ |
| case IORING_OP_READV: |
| case IORING_OP_READ_FIXED: |
| case IORING_OP_SENDMSG: |
| case IORING_OP_RECVMSG: |
| case IORING_OP_ACCEPT: |
| case IORING_OP_POLL_ADD: |
| case IORING_OP_CONNECT: |
| /* |
| * We know REQ_F_ISREG is not set on some of these |
| * opcodes, but this enables us to keep the check in |
| * just one place. |
| */ |
| if (!(req->flags & REQ_F_ISREG)) |
| req->work.flags |= IO_WQ_WORK_UNBOUND; |
| break; |
| } |
| if (io_sqe_needs_user(req->sqe)) |
| req->work.flags |= IO_WQ_WORK_NEEDS_USER; |
| } |
| |
| *link = io_prep_linked_timeout(req); |
| return do_hashed; |
| } |
| |
| static inline void io_queue_async_work(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| struct io_kiocb *link; |
| bool do_hashed; |
| |
| do_hashed = io_prep_async_work(req, &link); |
| |
| trace_io_uring_queue_async_work(ctx, do_hashed, req, &req->work, |
| req->flags); |
| if (!do_hashed) { |
| io_wq_enqueue(ctx->io_wq, &req->work); |
| } else { |
| io_wq_enqueue_hashed(ctx->io_wq, &req->work, |
| file_inode(req->file)); |
| } |
| |
| if (link) |
| io_queue_linked_timeout(link); |
| } |
| |
| static void io_kill_timeout(struct io_kiocb *req) |
| { |
| int ret; |
| |
| ret = hrtimer_try_to_cancel(&req->io->timeout.timer); |
| if (ret != -1) { |
| atomic_inc(&req->ctx->cq_timeouts); |
| list_del_init(&req->list); |
| io_cqring_fill_event(req, 0); |
| io_put_req(req); |
| } |
| } |
| |
| static void io_kill_timeouts(struct io_ring_ctx *ctx) |
| { |
| struct io_kiocb *req, *tmp; |
| |
| spin_lock_irq(&ctx->completion_lock); |
| list_for_each_entry_safe(req, tmp, &ctx->timeout_list, list) |
| io_kill_timeout(req); |
| spin_unlock_irq(&ctx->completion_lock); |
| } |
| |
| static void io_commit_cqring(struct io_ring_ctx *ctx) |
| { |
| struct io_kiocb *req; |
| |
| while ((req = io_get_timeout_req(ctx)) != NULL) |
| io_kill_timeout(req); |
| |
| __io_commit_cqring(ctx); |
| |
| while ((req = io_get_deferred_req(ctx)) != NULL) { |
| req->flags |= REQ_F_IO_DRAINED; |
| io_queue_async_work(req); |
| } |
| } |
| |
| static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) |
| { |
| struct io_rings *rings = ctx->rings; |
| unsigned tail; |
| |
| tail = ctx->cached_cq_tail; |
| /* |
| * writes to the cq entry need to come after reading head; the |
| * control dependency is enough as we're using WRITE_ONCE to |
| * fill the cq entry |
| */ |
| if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries) |
| return NULL; |
| |
| ctx->cached_cq_tail++; |
| return &rings->cqes[tail & ctx->cq_mask]; |
| } |
| |
| static void io_cqring_ev_posted(struct io_ring_ctx *ctx) |
| { |
| if (waitqueue_active(&ctx->wait)) |
| wake_up(&ctx->wait); |
| if (waitqueue_active(&ctx->sqo_wait)) |
| wake_up(&ctx->sqo_wait); |
| if (ctx->cq_ev_fd) |
| eventfd_signal(ctx->cq_ev_fd, 1); |
| } |
| |
| /* Returns true if there are no backlogged entries after the flush */ |
| static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force) |
| { |
| struct io_rings *rings = ctx->rings; |
| struct io_uring_cqe *cqe; |
| struct io_kiocb *req; |
| unsigned long flags; |
| LIST_HEAD(list); |
| |
| if (!force) { |
| if (list_empty_careful(&ctx->cq_overflow_list)) |
| return true; |
| if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) == |
| rings->cq_ring_entries)) |
| return false; |
| } |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| |
| /* if force is set, the ring is going away. always drop after that */ |
| if (force) |
| ctx->cq_overflow_flushed = true; |
| |
| cqe = NULL; |
| while (!list_empty(&ctx->cq_overflow_list)) { |
| cqe = io_get_cqring(ctx); |
| if (!cqe && !force) |
| break; |
| |
| req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb, |
| list); |
| list_move(&req->list, &list); |
| if (cqe) { |
| WRITE_ONCE(cqe->user_data, req->user_data); |
| WRITE_ONCE(cqe->res, req->result); |
| WRITE_ONCE(cqe->flags, 0); |
| } else { |
| WRITE_ONCE(ctx->rings->cq_overflow, |
| atomic_inc_return(&ctx->cached_cq_overflow)); |
| } |
| } |
| |
| io_commit_cqring(ctx); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| io_cqring_ev_posted(ctx); |
| |
| while (!list_empty(&list)) { |
| req = list_first_entry(&list, struct io_kiocb, list); |
| list_del(&req->list); |
| io_put_req(req); |
| } |
| |
| return cqe != NULL; |
| } |
| |
| static void io_cqring_fill_event(struct io_kiocb *req, long res) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| struct io_uring_cqe *cqe; |
| |
| trace_io_uring_complete(ctx, req->user_data, res); |
| |
| /* |
| * If we can't get a cq entry, userspace overflowed the |
| * submission (by quite a lot). Increment the overflow count in |
| * the ring. |
| */ |
| cqe = io_get_cqring(ctx); |
| if (likely(cqe)) { |
| WRITE_ONCE(cqe->user_data, req->user_data); |
| WRITE_ONCE(cqe->res, res); |
| WRITE_ONCE(cqe->flags, 0); |
| } else if (ctx->cq_overflow_flushed) { |
| WRITE_ONCE(ctx->rings->cq_overflow, |
| atomic_inc_return(&ctx->cached_cq_overflow)); |
| } else { |
| refcount_inc(&req->refs); |
| req->result = res; |
| list_add_tail(&req->list, &ctx->cq_overflow_list); |
| } |
| } |
| |
| static void io_cqring_add_event(struct io_kiocb *req, long res) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| io_cqring_fill_event(req, res); |
| io_commit_cqring(ctx); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| |
| io_cqring_ev_posted(ctx); |
| } |
| |
| static inline bool io_is_fallback_req(struct io_kiocb *req) |
| { |
| return req == (struct io_kiocb *) |
| ((unsigned long) req->ctx->fallback_req & ~1UL); |
| } |
| |
| static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx) |
| { |
| struct io_kiocb *req; |
| |
| req = ctx->fallback_req; |
| if (!test_and_set_bit_lock(0, (unsigned long *) ctx->fallback_req)) |
| return req; |
| |
| return NULL; |
| } |
| |
| static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx, |
| struct io_submit_state *state) |
| { |
| gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; |
| struct io_kiocb *req; |
| |
| if (!percpu_ref_tryget(&ctx->refs)) |
| return NULL; |
| |
| if (!state) { |
| req = kmem_cache_alloc(req_cachep, gfp); |
| if (unlikely(!req)) |
| goto fallback; |
| } else if (!state->free_reqs) { |
| size_t sz; |
| int ret; |
| |
| sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs)); |
| ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs); |
| |
| /* |
| * Bulk alloc is all-or-nothing. If we fail to get a batch, |
| * retry single alloc to be on the safe side. |
| */ |
| if (unlikely(ret <= 0)) { |
| state->reqs[0] = kmem_cache_alloc(req_cachep, gfp); |
| if (!state->reqs[0]) |
| goto fallback; |
| ret = 1; |
| } |
| state->free_reqs = ret - 1; |
| state->cur_req = 1; |
| req = state->reqs[0]; |
| } else { |
| req = state->reqs[state->cur_req]; |
| state->free_reqs--; |
| state->cur_req++; |
| } |
| |
| got_it: |
| req->io = NULL; |
| req->ring_file = NULL; |
| req->file = NULL; |
| req->ctx = ctx; |
| req->flags = 0; |
| /* one is dropped after submission, the other at completion */ |
| refcount_set(&req->refs, 2); |
| req->result = 0; |
| INIT_IO_WORK(&req->work, io_wq_submit_work); |
| return req; |
| fallback: |
| req = io_get_fallback_req(ctx); |
| if (req) |
| goto got_it; |
| percpu_ref_put(&ctx->refs); |
| return NULL; |
| } |
| |
| static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr) |
| { |
| if (*nr) { |
| kmem_cache_free_bulk(req_cachep, *nr, reqs); |
| percpu_ref_put_many(&ctx->refs, *nr); |
| *nr = 0; |
| } |
| } |
| |
| static void __io_free_req(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| if (req->io) |
| kfree(req->io); |
| if (req->file && !(req->flags & REQ_F_FIXED_FILE)) |
| fput(req->file); |
| if (req->flags & REQ_F_INFLIGHT) { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ctx->inflight_lock, flags); |
| list_del(&req->inflight_entry); |
| if (waitqueue_active(&ctx->inflight_wait)) |
| wake_up(&ctx->inflight_wait); |
| spin_unlock_irqrestore(&ctx->inflight_lock, flags); |
| } |
| percpu_ref_put(&ctx->refs); |
| if (likely(!io_is_fallback_req(req))) |
| kmem_cache_free(req_cachep, req); |
| else |
| clear_bit_unlock(0, (unsigned long *) ctx->fallback_req); |
| } |
| |
| static bool io_link_cancel_timeout(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| int ret; |
| |
| ret = hrtimer_try_to_cancel(&req->io->timeout.timer); |
| if (ret != -1) { |
| io_cqring_fill_event(req, -ECANCELED); |
| io_commit_cqring(ctx); |
| req->flags &= ~REQ_F_LINK; |
| io_put_req(req); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| bool wake_ev = false; |
| |
| /* Already got next link */ |
| if (req->flags & REQ_F_LINK_NEXT) |
| return; |
| |
| /* |
| * The list should never be empty when we are called here. But could |
| * potentially happen if the chain is messed up, check to be on the |
| * safe side. |
| */ |
| while (!list_empty(&req->link_list)) { |
| struct io_kiocb *nxt = list_first_entry(&req->link_list, |
| struct io_kiocb, link_list); |
| |
| if (unlikely((req->flags & REQ_F_LINK_TIMEOUT) && |
| (nxt->flags & REQ_F_TIMEOUT))) { |
| list_del_init(&nxt->link_list); |
| wake_ev |= io_link_cancel_timeout(nxt); |
| req->flags &= ~REQ_F_LINK_TIMEOUT; |
| continue; |
| } |
| |
| list_del_init(&req->link_list); |
| if (!list_empty(&nxt->link_list)) |
| nxt->flags |= REQ_F_LINK; |
| *nxtptr = nxt; |
| break; |
| } |
| |
| req->flags |= REQ_F_LINK_NEXT; |
| if (wake_ev) |
| io_cqring_ev_posted(ctx); |
| } |
| |
| /* |
| * Called if REQ_F_LINK is set, and we fail the head request |
| */ |
| static void io_fail_links(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| |
| while (!list_empty(&req->link_list)) { |
| struct io_kiocb *link = list_first_entry(&req->link_list, |
| struct io_kiocb, link_list); |
| |
| list_del_init(&link->link_list); |
| trace_io_uring_fail_link(req, link); |
| |
| if ((req->flags & REQ_F_LINK_TIMEOUT) && |
| link->sqe->opcode == IORING_OP_LINK_TIMEOUT) { |
| io_link_cancel_timeout(link); |
| } else { |
| io_cqring_fill_event(link, -ECANCELED); |
| __io_double_put_req(link); |
| } |
| req->flags &= ~REQ_F_LINK_TIMEOUT; |
| } |
| |
| io_commit_cqring(ctx); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| io_cqring_ev_posted(ctx); |
| } |
| |
| static void io_req_find_next(struct io_kiocb *req, struct io_kiocb **nxt) |
| { |
| if (likely(!(req->flags & REQ_F_LINK))) |
| return; |
| |
| /* |
| * If LINK is set, we have dependent requests in this chain. If we |
| * didn't fail this request, queue the first one up, moving any other |
| * dependencies to the next request. In case of failure, fail the rest |
| * of the chain. |
| */ |
| if (req->flags & REQ_F_FAIL_LINK) { |
| io_fail_links(req); |
| } else if ((req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_COMP_LOCKED)) == |
| REQ_F_LINK_TIMEOUT) { |
| struct io_ring_ctx *ctx = req->ctx; |
| unsigned long flags; |
| |
| /* |
| * If this is a timeout link, we could be racing with the |
| * timeout timer. Grab the completion lock for this case to |
| * protect against that. |
| */ |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| io_req_link_next(req, nxt); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| } else { |
| io_req_link_next(req, nxt); |
| } |
| } |
| |
| static void io_free_req(struct io_kiocb *req) |
| { |
| struct io_kiocb *nxt = NULL; |
| |
| io_req_find_next(req, &nxt); |
| __io_free_req(req); |
| |
| if (nxt) |
| io_queue_async_work(nxt); |
| } |
| |
| /* |
| * Drop reference to request, return next in chain (if there is one) if this |
| * was the last reference to this request. |
| */ |
| __attribute__((nonnull)) |
| static void io_put_req_find_next(struct io_kiocb *req, struct io_kiocb **nxtptr) |
| { |
| io_req_find_next(req, nxtptr); |
| |
| if (refcount_dec_and_test(&req->refs)) |
| __io_free_req(req); |
| } |
| |
| static void io_put_req(struct io_kiocb *req) |
| { |
| if (refcount_dec_and_test(&req->refs)) |
| io_free_req(req); |
| } |
| |
| /* |
| * Must only be used if we don't need to care about links, usually from |
| * within the completion handling itself. |
| */ |
| static void __io_double_put_req(struct io_kiocb *req) |
| { |
| /* drop both submit and complete references */ |
| if (refcount_sub_and_test(2, &req->refs)) |
| __io_free_req(req); |
| } |
| |
| static void io_double_put_req(struct io_kiocb *req) |
| { |
| /* drop both submit and complete references */ |
| if (refcount_sub_and_test(2, &req->refs)) |
| io_free_req(req); |
| } |
| |
| static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush) |
| { |
| struct io_rings *rings = ctx->rings; |
| |
| /* |
| * noflush == true is from the waitqueue handler, just ensure we wake |
| * up the task, and the next invocation will flush the entries. We |
| * cannot safely to it from here. |
| */ |
| if (noflush && !list_empty(&ctx->cq_overflow_list)) |
| return -1U; |
| |
| io_cqring_overflow_flush(ctx, false); |
| |
| /* See comment at the top of this file */ |
| smp_rmb(); |
| return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head); |
| } |
| |
| static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) |
| { |
| struct io_rings *rings = ctx->rings; |
| |
| /* make sure SQ entry isn't read before tail */ |
| return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head; |
| } |
| |
| /* |
| * Find and free completed poll iocbs |
| */ |
| static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, |
| struct list_head *done) |
| { |
| void *reqs[IO_IOPOLL_BATCH]; |
| struct io_kiocb *req; |
| int to_free; |
| |
| to_free = 0; |
| while (!list_empty(done)) { |
| req = list_first_entry(done, struct io_kiocb, list); |
| list_del(&req->list); |
| |
| io_cqring_fill_event(req, req->result); |
| (*nr_events)++; |
| |
| if (refcount_dec_and_test(&req->refs)) { |
| /* If we're not using fixed files, we have to pair the |
| * completion part with the file put. Use regular |
| * completions for those, only batch free for fixed |
| * file and non-linked commands. |
| */ |
| if (((req->flags & (REQ_F_FIXED_FILE|REQ_F_LINK)) == |
| REQ_F_FIXED_FILE) && !io_is_fallback_req(req) && |
| !req->io) { |
| reqs[to_free++] = req; |
| if (to_free == ARRAY_SIZE(reqs)) |
| io_free_req_many(ctx, reqs, &to_free); |
| } else { |
| io_free_req(req); |
| } |
| } |
| } |
| |
| io_commit_cqring(ctx); |
| io_free_req_many(ctx, reqs, &to_free); |
| } |
| |
| static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, |
| long min) |
| { |
| struct io_kiocb *req, *tmp; |
| LIST_HEAD(done); |
| bool spin; |
| int ret; |
| |
| /* |
| * Only spin for completions if we don't have multiple devices hanging |
| * off our complete list, and we're under the requested amount. |
| */ |
| spin = !ctx->poll_multi_file && *nr_events < min; |
| |
| ret = 0; |
| list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) { |
| struct kiocb *kiocb = &req->rw; |
| |
| /* |
| * Move completed entries to our local list. If we find a |
| * request that requires polling, break out and complete |
| * the done list first, if we have entries there. |
| */ |
| if (req->flags & REQ_F_IOPOLL_COMPLETED) { |
| list_move_tail(&req->list, &done); |
| continue; |
| } |
| if (!list_empty(&done)) |
| break; |
| |
| ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin); |
| if (ret < 0) |
| break; |
| |
| if (ret && spin) |
| spin = false; |
| ret = 0; |
| } |
| |
| if (!list_empty(&done)) |
| io_iopoll_complete(ctx, nr_events, &done); |
| |
| return ret; |
| } |
| |
| /* |
| * Poll for a minimum of 'min' events. Note that if min == 0 we consider that a |
| * non-spinning poll check - we'll still enter the driver poll loop, but only |
| * as a non-spinning completion check. |
| */ |
| static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events, |
| long min) |
| { |
| while (!list_empty(&ctx->poll_list) && !need_resched()) { |
| int ret; |
| |
| ret = io_do_iopoll(ctx, nr_events, min); |
| if (ret < 0) |
| return ret; |
| if (!min || *nr_events >= min) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| /* |
| * We can't just wait for polled events to come to us, we have to actively |
| * find and complete them. |
| */ |
| static void io_iopoll_reap_events(struct io_ring_ctx *ctx) |
| { |
| if (!(ctx->flags & IORING_SETUP_IOPOLL)) |
| return; |
| |
| mutex_lock(&ctx->uring_lock); |
| while (!list_empty(&ctx->poll_list)) { |
| unsigned int nr_events = 0; |
| |
| io_iopoll_getevents(ctx, &nr_events, 1); |
| |
| /* |
| * Ensure we allow local-to-the-cpu processing to take place, |
| * in this case we need to ensure that we reap all events. |
| */ |
| cond_resched(); |
| } |
| mutex_unlock(&ctx->uring_lock); |
| } |
| |
| static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, |
| long min) |
| { |
| int iters = 0, ret = 0; |
| |
| do { |
| int tmin = 0; |
| |
| /* |
| * Don't enter poll loop if we already have events pending. |
| * If we do, we can potentially be spinning for commands that |
| * already triggered a CQE (eg in error). |
| */ |
| if (io_cqring_events(ctx, false)) |
| break; |
| |
| /* |
| * If a submit got punted to a workqueue, we can have the |
| * application entering polling for a command before it gets |
| * issued. That app will hold the uring_lock for the duration |
| * of the poll right here, so we need to take a breather every |
| * now and then to ensure that the issue has a chance to add |
| * the poll to the issued list. Otherwise we can spin here |
| * forever, while the workqueue is stuck trying to acquire the |
| * very same mutex. |
| */ |
| if (!(++iters & 7)) { |
| mutex_unlock(&ctx->uring_lock); |
| mutex_lock(&ctx->uring_lock); |
| } |
| |
| if (*nr_events < min) |
| tmin = min - *nr_events; |
| |
| ret = io_iopoll_getevents(ctx, nr_events, tmin); |
| if (ret <= 0) |
| break; |
| ret = 0; |
| } while (min && !*nr_events && !need_resched()); |
| |
| return ret; |
| } |
| |
| static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, |
| long min) |
| { |
| int ret; |
| |
| /* |
| * We disallow the app entering submit/complete with polling, but we |
| * still need to lock the ring to prevent racing with polled issue |
| * that got punted to a workqueue. |
| */ |
| mutex_lock(&ctx->uring_lock); |
| ret = __io_iopoll_check(ctx, nr_events, min); |
| mutex_unlock(&ctx->uring_lock); |
| return ret; |
| } |
| |
| static void kiocb_end_write(struct io_kiocb *req) |
| { |
| /* |
| * Tell lockdep we inherited freeze protection from submission |
| * thread. |
| */ |
| if (req->flags & REQ_F_ISREG) { |
| struct inode *inode = file_inode(req->file); |
| |
| __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); |
| } |
| file_end_write(req->file); |
| } |
| |
| static inline void req_set_fail_links(struct io_kiocb *req) |
| { |
| if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK) |
| req->flags |= REQ_F_FAIL_LINK; |
| } |
| |
| static void io_complete_rw_common(struct kiocb *kiocb, long res) |
| { |
| struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); |
| |
| if (kiocb->ki_flags & IOCB_WRITE) |
| kiocb_end_write(req); |
| |
| if (res != req->result) |
| req_set_fail_links(req); |
| io_cqring_add_event(req, res); |
| } |
| |
| static void io_complete_rw(struct kiocb *kiocb, long res, long res2) |
| { |
| struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); |
| |
| io_complete_rw_common(kiocb, res); |
| io_put_req(req); |
| } |
| |
| static struct io_kiocb *__io_complete_rw(struct kiocb *kiocb, long res) |
| { |
| struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); |
| struct io_kiocb *nxt = NULL; |
| |
| io_complete_rw_common(kiocb, res); |
| io_put_req_find_next(req, &nxt); |
| |
| return nxt; |
| } |
| |
| static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) |
| { |
| struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw); |
| |
| if (kiocb->ki_flags & IOCB_WRITE) |
| kiocb_end_write(req); |
| |
| if (res != req->result) |
| req_set_fail_links(req); |
| req->result = res; |
| if (res != -EAGAIN) |
| req->flags |= REQ_F_IOPOLL_COMPLETED; |
| } |
| |
| /* |
| * After the iocb has been issued, it's safe to be found on the poll list. |
| * Adding the kiocb to the list AFTER submission ensures that we don't |
| * find it from a io_iopoll_getevents() thread before the issuer is done |
| * accessing the kiocb cookie. |
| */ |
| static void io_iopoll_req_issued(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| /* |
| * Track whether we have multiple files in our lists. This will impact |
| * how we do polling eventually, not spinning if we're on potentially |
| * different devices. |
| */ |
| if (list_empty(&ctx->poll_list)) { |
| ctx->poll_multi_file = false; |
| } else if (!ctx->poll_multi_file) { |
| struct io_kiocb *list_req; |
| |
| list_req = list_first_entry(&ctx->poll_list, struct io_kiocb, |
| list); |
| if (list_req->rw.ki_filp != req->rw.ki_filp) |
| ctx->poll_multi_file = true; |
| } |
| |
| /* |
| * For fast devices, IO may have already completed. If it has, add |
| * it to the front so we find it first. |
| */ |
| if (req->flags & REQ_F_IOPOLL_COMPLETED) |
| list_add(&req->list, &ctx->poll_list); |
| else |
| list_add_tail(&req->list, &ctx->poll_list); |
| } |
| |
| static void io_file_put(struct io_submit_state *state) |
| { |
| if (state->file) { |
| int diff = state->has_refs - state->used_refs; |
| |
| if (diff) |
| fput_many(state->file, diff); |
| state->file = NULL; |
| } |
| } |
| |
| /* |
| * Get as many references to a file as we have IOs left in this submission, |
| * assuming most submissions are for one file, or at least that each file |
| * has more than one submission. |
| */ |
| static struct file *io_file_get(struct io_submit_state *state, int fd) |
| { |
| if (!state) |
| return fget(fd); |
| |
| if (state->file) { |
| if (state->fd == fd) { |
| state->used_refs++; |
| state->ios_left--; |
| return state->file; |
| } |
| io_file_put(state); |
| } |
| state->file = fget_many(fd, state->ios_left); |
| if (!state->file) |
| return NULL; |
| |
| state->fd = fd; |
| state->has_refs = state->ios_left; |
| state->used_refs = 1; |
| state->ios_left--; |
| return state->file; |
| } |
| |
| /* |
| * If we tracked the file through the SCM inflight mechanism, we could support |
| * any file. For now, just ensure that anything potentially problematic is done |
| * inline. |
| */ |
| static bool io_file_supports_async(struct file *file) |
| { |
| umode_t mode = file_inode(file)->i_mode; |
| |
| if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISSOCK(mode)) |
| return true; |
| if (S_ISREG(mode) && file->f_op != &io_uring_fops) |
| return true; |
| |
| return false; |
| } |
| |
| static int io_prep_rw(struct io_kiocb *req, bool force_nonblock) |
| { |
| const struct io_uring_sqe *sqe = req->sqe; |
| struct io_ring_ctx *ctx = req->ctx; |
| struct kiocb *kiocb = &req->rw; |
| unsigned ioprio; |
| int ret; |
| |
| if (!req->file) |
| return -EBADF; |
| |
| if (S_ISREG(file_inode(req->file)->i_mode)) |
| req->flags |= REQ_F_ISREG; |
| |
| kiocb->ki_pos = READ_ONCE(sqe->off); |
| kiocb->ki_flags = iocb_flags(kiocb->ki_filp); |
| kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp)); |
| |
| ioprio = READ_ONCE(sqe->ioprio); |
| if (ioprio) { |
| ret = ioprio_check_cap(ioprio); |
| if (ret) |
| return ret; |
| |
| kiocb->ki_ioprio = ioprio; |
| } else |
| kiocb->ki_ioprio = get_current_ioprio(); |
| |
| ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags)); |
| if (unlikely(ret)) |
| return ret; |
| |
| /* don't allow async punt if RWF_NOWAIT was requested */ |
| if ((kiocb->ki_flags & IOCB_NOWAIT) || |
| (req->file->f_flags & O_NONBLOCK)) |
| req->flags |= REQ_F_NOWAIT; |
| |
| if (force_nonblock) |
| kiocb->ki_flags |= IOCB_NOWAIT; |
| |
| if (ctx->flags & IORING_SETUP_IOPOLL) { |
| if (!(kiocb->ki_flags & IOCB_DIRECT) || |
| !kiocb->ki_filp->f_op->iopoll) |
| return -EOPNOTSUPP; |
| |
| kiocb->ki_flags |= IOCB_HIPRI; |
| kiocb->ki_complete = io_complete_rw_iopoll; |
| req->result = 0; |
| } else { |
| if (kiocb->ki_flags & IOCB_HIPRI) |
| return -EINVAL; |
| kiocb->ki_complete = io_complete_rw; |
| } |
| return 0; |
| } |
| |
| static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) |
| { |
| switch (ret) { |
| case -EIOCBQUEUED: |
| break; |
| case -ERESTARTSYS: |
| case -ERESTARTNOINTR: |
| case -ERESTARTNOHAND: |
| case -ERESTART_RESTARTBLOCK: |
| /* |
| * We can't just restart the syscall, since previously |
| * submitted sqes may already be in progress. Just fail this |
| * IO with EINTR. |
| */ |
| ret = -EINTR; |
| /* fall through */ |
| default: |
| kiocb->ki_complete(kiocb, ret, 0); |
| } |
| } |
| |
| static void kiocb_done(struct kiocb *kiocb, ssize_t ret, struct io_kiocb **nxt, |
| bool in_async) |
| { |
| if (in_async && ret >= 0 && kiocb->ki_complete == io_complete_rw) |
| *nxt = __io_complete_rw(kiocb, ret); |
| else |
| io_rw_done(kiocb, ret); |
| } |
| |
| static ssize_t io_import_fixed(struct io_ring_ctx *ctx, int rw, |
| const struct io_uring_sqe *sqe, |
| struct iov_iter *iter) |
| { |
| size_t len = READ_ONCE(sqe->len); |
| struct io_mapped_ubuf *imu; |
| unsigned index, buf_index; |
| size_t offset; |
| u64 buf_addr; |
| |
| /* attempt to use fixed buffers without having provided iovecs */ |
| if (unlikely(!ctx->user_bufs)) |
| return -EFAULT; |
| |
| buf_index = READ_ONCE(sqe->buf_index); |
| if (unlikely(buf_index >= ctx->nr_user_bufs)) |
| return -EFAULT; |
| |
| index = array_index_nospec(buf_index, ctx->nr_user_bufs); |
| imu = &ctx->user_bufs[index]; |
| buf_addr = READ_ONCE(sqe->addr); |
| |
| /* overflow */ |
| if (buf_addr + len < buf_addr) |
| return -EFAULT; |
| /* not inside the mapped region */ |
| if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len) |
| return -EFAULT; |
| |
| /* |
| * May not be a start of buffer, set size appropriately |
| * and advance us to the beginning. |
| */ |
| offset = buf_addr - imu->ubuf; |
| iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); |
| |
| if (offset) { |
| /* |
| * Don't use iov_iter_advance() here, as it's really slow for |
| * using the latter parts of a big fixed buffer - it iterates |
| * over each segment manually. We can cheat a bit here, because |
| * we know that: |
| * |
| * 1) it's a BVEC iter, we set it up |
| * 2) all bvecs are PAGE_SIZE in size, except potentially the |
| * first and last bvec |
| * |
| * So just find our index, and adjust the iterator afterwards. |
| * If the offset is within the first bvec (or the whole first |
| * bvec, just use iov_iter_advance(). This makes it easier |
| * since we can just skip the first segment, which may not |
| * be PAGE_SIZE aligned. |
| */ |
| const struct bio_vec *bvec = imu->bvec; |
| |
| if (offset <= bvec->bv_len) { |
| iov_iter_advance(iter, offset); |
| } else { |
| unsigned long seg_skip; |
| |
| /* skip first vec */ |
| offset -= bvec->bv_len; |
| seg_skip = 1 + (offset >> PAGE_SHIFT); |
| |
| iter->bvec = bvec + seg_skip; |
| iter->nr_segs -= seg_skip; |
| iter->count -= bvec->bv_len + offset; |
| iter->iov_offset = offset & ~PAGE_MASK; |
| } |
| } |
| |
| return len; |
| } |
| |
| static ssize_t io_import_iovec(int rw, struct io_kiocb *req, |
| struct iovec **iovec, struct iov_iter *iter) |
| { |
| const struct io_uring_sqe *sqe = req->sqe; |
| void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr)); |
| size_t sqe_len = READ_ONCE(sqe->len); |
| u8 opcode; |
| |
| /* |
| * We're reading ->opcode for the second time, but the first read |
| * doesn't care whether it's _FIXED or not, so it doesn't matter |
| * whether ->opcode changes concurrently. The first read does care |
| * about whether it is a READ or a WRITE, so we don't trust this read |
| * for that purpose and instead let the caller pass in the read/write |
| * flag. |
| */ |
| opcode = READ_ONCE(sqe->opcode); |
| if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { |
| *iovec = NULL; |
| return io_import_fixed(req->ctx, rw, sqe, iter); |
| } |
| |
| if (req->io) { |
| struct io_async_rw *iorw = &req->io->rw; |
| |
| *iovec = iorw->iov; |
| iov_iter_init(iter, rw, *iovec, iorw->nr_segs, iorw->size); |
| if (iorw->iov == iorw->fast_iov) |
| *iovec = NULL; |
| return iorw->size; |
| } |
| |
| if (!req->has_user) |
| return -EFAULT; |
| |
| #ifdef CONFIG_COMPAT |
| if (req->ctx->compat) |
| return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV, |
| iovec, iter); |
| #endif |
| |
| return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); |
| } |
| |
| /* |
| * For files that don't have ->read_iter() and ->write_iter(), handle them |
| * by looping over ->read() or ->write() manually. |
| */ |
| static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb, |
| struct iov_iter *iter) |
| { |
| ssize_t ret = 0; |
| |
| /* |
| * Don't support polled IO through this interface, and we can't |
| * support non-blocking either. For the latter, this just causes |
| * the kiocb to be handled from an async context. |
| */ |
| if (kiocb->ki_flags & IOCB_HIPRI) |
| return -EOPNOTSUPP; |
| if (kiocb->ki_flags & IOCB_NOWAIT) |
| return -EAGAIN; |
| |
| while (iov_iter_count(iter)) { |
| struct iovec iovec; |
| ssize_t nr; |
| |
| if (!iov_iter_is_bvec(iter)) { |
| iovec = iov_iter_iovec(iter); |
| } else { |
| /* fixed buffers import bvec */ |
| iovec.iov_base = kmap(iter->bvec->bv_page) |
| + iter->iov_offset; |
| iovec.iov_len = min(iter->count, |
| iter->bvec->bv_len - iter->iov_offset); |
| } |
| |
| if (rw == READ) { |
| nr = file->f_op->read(file, iovec.iov_base, |
| iovec.iov_len, &kiocb->ki_pos); |
| } else { |
| nr = file->f_op->write(file, iovec.iov_base, |
| iovec.iov_len, &kiocb->ki_pos); |
| } |
| |
| if (iov_iter_is_bvec(iter)) |
| kunmap(iter->bvec->bv_page); |
| |
| if (nr < 0) { |
| if (!ret) |
| ret = nr; |
| break; |
| } |
| ret += nr; |
| if (nr != iovec.iov_len) |
| break; |
| iov_iter_advance(iter, nr); |
| } |
| |
| return ret; |
| } |
| |
| static void io_req_map_io(struct io_kiocb *req, ssize_t io_size, |
| struct iovec *iovec, struct iovec *fast_iov, |
| struct iov_iter *iter) |
| { |
| req->io->rw.nr_segs = iter->nr_segs; |
| req->io->rw.size = io_size; |
| req->io->rw.iov = iovec; |
| if (!req->io->rw.iov) { |
| req->io->rw.iov = req->io->rw.fast_iov; |
| memcpy(req->io->rw.iov, fast_iov, |
| sizeof(struct iovec) * iter->nr_segs); |
| } |
| } |
| |
| static int io_setup_async_io(struct io_kiocb *req, ssize_t io_size, |
| struct iovec *iovec, struct iovec *fast_iov, |
| struct iov_iter *iter) |
| { |
| req->io = kmalloc(sizeof(*req->io), GFP_KERNEL); |
| if (req->io) { |
| io_req_map_io(req, io_size, iovec, fast_iov, iter); |
| memcpy(&req->io->sqe, req->sqe, sizeof(req->io->sqe)); |
| req->sqe = &req->io->sqe; |
| return 0; |
| } |
| |
| return -ENOMEM; |
| } |
| |
| static int io_read_prep(struct io_kiocb *req, struct iovec **iovec, |
| struct iov_iter *iter, bool force_nonblock) |
| { |
| ssize_t ret; |
| |
| ret = io_prep_rw(req, force_nonblock); |
| if (ret) |
| return ret; |
| |
| if (unlikely(!(req->file->f_mode & FMODE_READ))) |
| return -EBADF; |
| |
| return io_import_iovec(READ, req, iovec, iter); |
| } |
| |
| static int io_read(struct io_kiocb *req, struct io_kiocb **nxt, |
| bool force_nonblock) |
| { |
| struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; |
| struct kiocb *kiocb = &req->rw; |
| struct iov_iter iter; |
| struct file *file; |
| size_t iov_count; |
| ssize_t io_size, ret; |
| |
| if (!req->io) { |
| ret = io_read_prep(req, &iovec, &iter, force_nonblock); |
| if (ret < 0) |
| return ret; |
| } else { |
| ret = io_import_iovec(READ, req, &iovec, &iter); |
| if (ret < 0) |
| return ret; |
| } |
| |
| file = req->file; |
| io_size = ret; |
| if (req->flags & REQ_F_LINK) |
| req->result = io_size; |
| |
| /* |
| * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so |
| * we know to async punt it even if it was opened O_NONBLOCK |
| */ |
| if (force_nonblock && !io_file_supports_async(file)) { |
| req->flags |= REQ_F_MUST_PUNT; |
| goto copy_iov; |
| } |
| |
| iov_count = iov_iter_count(&iter); |
| ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count); |
| if (!ret) { |
| ssize_t ret2; |
| |
| if (file->f_op->read_iter) |
| ret2 = call_read_iter(file, kiocb, &iter); |
| else |
| ret2 = loop_rw_iter(READ, file, kiocb, &iter); |
| |
| /* |
| * In case of a short read, punt to async. This can happen |
| * if we have data partially cached. Alternatively we can |
| * return the short read, in which case the application will |
| * need to issue another SQE and wait for it. That SQE will |
| * need async punt anyway, so it's more efficient to do it |
| * here. |
| */ |
| if (force_nonblock && !(req->flags & REQ_F_NOWAIT) && |
| (req->flags & REQ_F_ISREG) && |
| ret2 > 0 && ret2 < io_size) |
| ret2 = -EAGAIN; |
| /* Catch -EAGAIN return for forced non-blocking submission */ |
| if (!force_nonblock || ret2 != -EAGAIN) { |
| kiocb_done(kiocb, ret2, nxt, req->in_async); |
| } else { |
| copy_iov: |
| ret = io_setup_async_io(req, io_size, iovec, |
| inline_vecs, &iter); |
| if (ret) |
| goto out_free; |
| return -EAGAIN; |
| } |
| } |
| out_free: |
| kfree(iovec); |
| return ret; |
| } |
| |
| static int io_write_prep(struct io_kiocb *req, struct iovec **iovec, |
| struct iov_iter *iter, bool force_nonblock) |
| { |
| ssize_t ret; |
| |
| ret = io_prep_rw(req, force_nonblock); |
| if (ret) |
| return ret; |
| |
| if (unlikely(!(req->file->f_mode & FMODE_WRITE))) |
| return -EBADF; |
| |
| return io_import_iovec(WRITE, req, iovec, iter); |
| } |
| |
| static int io_write(struct io_kiocb *req, struct io_kiocb **nxt, |
| bool force_nonblock) |
| { |
| struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; |
| struct kiocb *kiocb = &req->rw; |
| struct iov_iter iter; |
| struct file *file; |
| size_t iov_count; |
| ssize_t ret, io_size; |
| |
| if (!req->io) { |
| ret = io_write_prep(req, &iovec, &iter, force_nonblock); |
| if (ret < 0) |
| return ret; |
| } else { |
| ret = io_import_iovec(WRITE, req, &iovec, &iter); |
| if (ret < 0) |
| return ret; |
| } |
| |
| file = kiocb->ki_filp; |
| io_size = ret; |
| if (req->flags & REQ_F_LINK) |
| req->result = io_size; |
| |
| /* |
| * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so |
| * we know to async punt it even if it was opened O_NONBLOCK |
| */ |
| if (force_nonblock && !io_file_supports_async(req->file)) { |
| req->flags |= REQ_F_MUST_PUNT; |
| goto copy_iov; |
| } |
| |
| /* file path doesn't support NOWAIT for non-direct_IO */ |
| if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) && |
| (req->flags & REQ_F_ISREG)) |
| goto copy_iov; |
| |
| iov_count = iov_iter_count(&iter); |
| ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count); |
| if (!ret) { |
| ssize_t ret2; |
| |
| /* |
| * Open-code file_start_write here to grab freeze protection, |
| * which will be released by another thread in |
| * io_complete_rw(). Fool lockdep by telling it the lock got |
| * released so that it doesn't complain about the held lock when |
| * we return to userspace. |
| */ |
| if (req->flags & REQ_F_ISREG) { |
| __sb_start_write(file_inode(file)->i_sb, |
| SB_FREEZE_WRITE, true); |
| __sb_writers_release(file_inode(file)->i_sb, |
| SB_FREEZE_WRITE); |
| } |
| kiocb->ki_flags |= IOCB_WRITE; |
| |
| if (file->f_op->write_iter) |
| ret2 = call_write_iter(file, kiocb, &iter); |
| else |
| ret2 = loop_rw_iter(WRITE, file, kiocb, &iter); |
| if (!force_nonblock || ret2 != -EAGAIN) { |
| kiocb_done(kiocb, ret2, nxt, req->in_async); |
| } else { |
| copy_iov: |
| ret = io_setup_async_io(req, io_size, iovec, |
| inline_vecs, &iter); |
| if (ret) |
| goto out_free; |
| return -EAGAIN; |
| } |
| } |
| out_free: |
| kfree(iovec); |
| return ret; |
| } |
| |
| /* |
| * IORING_OP_NOP just posts a completion event, nothing else. |
| */ |
| static int io_nop(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| |
| io_cqring_add_event(req, 0); |
| io_put_req(req); |
| return 0; |
| } |
| |
| static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| if (!req->file) |
| return -EBADF; |
| |
| if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) |
| return -EINVAL; |
| |
| return 0; |
| } |
| |
| static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt, bool force_nonblock) |
| { |
| loff_t sqe_off = READ_ONCE(sqe->off); |
| loff_t sqe_len = READ_ONCE(sqe->len); |
| loff_t end = sqe_off + sqe_len; |
| unsigned fsync_flags; |
| int ret; |
| |
| fsync_flags = READ_ONCE(sqe->fsync_flags); |
| if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC)) |
| return -EINVAL; |
| |
| ret = io_prep_fsync(req, sqe); |
| if (ret) |
| return ret; |
| |
| /* fsync always requires a blocking context */ |
| if (force_nonblock) |
| return -EAGAIN; |
| |
| ret = vfs_fsync_range(req->rw.ki_filp, sqe_off, |
| end > 0 ? end : LLONG_MAX, |
| fsync_flags & IORING_FSYNC_DATASYNC); |
| |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_cqring_add_event(req, ret); |
| io_put_req_find_next(req, nxt); |
| return 0; |
| } |
| |
| static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| int ret = 0; |
| |
| if (!req->file) |
| return -EBADF; |
| |
| if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) |
| return -EINVAL; |
| |
| return ret; |
| } |
| |
| static int io_sync_file_range(struct io_kiocb *req, |
| const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt, |
| bool force_nonblock) |
| { |
| loff_t sqe_off; |
| loff_t sqe_len; |
| unsigned flags; |
| int ret; |
| |
| ret = io_prep_sfr(req, sqe); |
| if (ret) |
| return ret; |
| |
| /* sync_file_range always requires a blocking context */ |
| if (force_nonblock) |
| return -EAGAIN; |
| |
| sqe_off = READ_ONCE(sqe->off); |
| sqe_len = READ_ONCE(sqe->len); |
| flags = READ_ONCE(sqe->sync_range_flags); |
| |
| ret = sync_file_range(req->rw.ki_filp, sqe_off, sqe_len, flags); |
| |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_cqring_add_event(req, ret); |
| io_put_req_find_next(req, nxt); |
| return 0; |
| } |
| |
| static int io_sendmsg_prep(struct io_kiocb *req, struct io_async_ctx *io) |
| { |
| #if defined(CONFIG_NET) |
| const struct io_uring_sqe *sqe = req->sqe; |
| struct user_msghdr __user *msg; |
| unsigned flags; |
| |
| flags = READ_ONCE(sqe->msg_flags); |
| msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr); |
| io->msg.iov = io->msg.fast_iov; |
| return sendmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.iov); |
| #else |
| return 0; |
| #endif |
| } |
| |
| static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt, bool force_nonblock) |
| { |
| #if defined(CONFIG_NET) |
| struct socket *sock; |
| int ret; |
| |
| if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| |
| sock = sock_from_file(req->file, &ret); |
| if (sock) { |
| struct io_async_ctx io, *copy; |
| struct sockaddr_storage addr; |
| struct msghdr *kmsg; |
| unsigned flags; |
| |
| flags = READ_ONCE(sqe->msg_flags); |
| if (flags & MSG_DONTWAIT) |
| req->flags |= REQ_F_NOWAIT; |
| else if (force_nonblock) |
| flags |= MSG_DONTWAIT; |
| |
| if (req->io) { |
| kmsg = &req->io->msg.msg; |
| kmsg->msg_name = &addr; |
| } else { |
| kmsg = &io.msg.msg; |
| kmsg->msg_name = &addr; |
| ret = io_sendmsg_prep(req, &io); |
| if (ret) |
| goto out; |
| } |
| |
| ret = __sys_sendmsg_sock(sock, kmsg, flags); |
| if (force_nonblock && ret == -EAGAIN) { |
| copy = kmalloc(sizeof(*copy), GFP_KERNEL); |
| if (!copy) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| memcpy(©->msg, &io.msg, sizeof(copy->msg)); |
| req->io = copy; |
| memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe)); |
| req->sqe = &req->io->sqe; |
| return ret; |
| } |
| if (ret == -ERESTARTSYS) |
| ret = -EINTR; |
| } |
| |
| out: |
| io_cqring_add_event(req, ret); |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_put_req_find_next(req, nxt); |
| return 0; |
| #else |
| return -EOPNOTSUPP; |
| #endif |
| } |
| |
| static int io_recvmsg_prep(struct io_kiocb *req, struct io_async_ctx *io) |
| { |
| #if defined(CONFIG_NET) |
| const struct io_uring_sqe *sqe = req->sqe; |
| struct user_msghdr __user *msg; |
| unsigned flags; |
| |
| flags = READ_ONCE(sqe->msg_flags); |
| msg = (struct user_msghdr __user *)(unsigned long) READ_ONCE(sqe->addr); |
| io->msg.iov = io->msg.fast_iov; |
| return recvmsg_copy_msghdr(&io->msg.msg, msg, flags, &io->msg.uaddr, |
| &io->msg.iov); |
| #else |
| return 0; |
| #endif |
| } |
| |
| static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt, bool force_nonblock) |
| { |
| #if defined(CONFIG_NET) |
| struct socket *sock; |
| int ret; |
| |
| if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| |
| sock = sock_from_file(req->file, &ret); |
| if (sock) { |
| struct user_msghdr __user *msg; |
| struct io_async_ctx io, *copy; |
| struct sockaddr_storage addr; |
| struct msghdr *kmsg; |
| unsigned flags; |
| |
| flags = READ_ONCE(sqe->msg_flags); |
| if (flags & MSG_DONTWAIT) |
| req->flags |= REQ_F_NOWAIT; |
| else if (force_nonblock) |
| flags |= MSG_DONTWAIT; |
| |
| msg = (struct user_msghdr __user *) (unsigned long) |
| READ_ONCE(sqe->addr); |
| if (req->io) { |
| kmsg = &req->io->msg.msg; |
| kmsg->msg_name = &addr; |
| } else { |
| kmsg = &io.msg.msg; |
| kmsg->msg_name = &addr; |
| ret = io_recvmsg_prep(req, &io); |
| if (ret) |
| goto out; |
| } |
| |
| ret = __sys_recvmsg_sock(sock, kmsg, msg, io.msg.uaddr, flags); |
| if (force_nonblock && ret == -EAGAIN) { |
| copy = kmalloc(sizeof(*copy), GFP_KERNEL); |
| if (!copy) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| memcpy(copy, &io, sizeof(*copy)); |
| req->io = copy; |
| memcpy(&req->io->sqe, req->sqe, sizeof(*req->sqe)); |
| req->sqe = &req->io->sqe; |
| return ret; |
| } |
| if (ret == -ERESTARTSYS) |
| ret = -EINTR; |
| } |
| |
| out: |
| io_cqring_add_event(req, ret); |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_put_req_find_next(req, nxt); |
| return 0; |
| #else |
| return -EOPNOTSUPP; |
| #endif |
| } |
| |
| static int io_accept(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt, bool force_nonblock) |
| { |
| #if defined(CONFIG_NET) |
| struct sockaddr __user *addr; |
| int __user *addr_len; |
| unsigned file_flags; |
| int flags, ret; |
| |
| if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) |
| return -EINVAL; |
| if (sqe->ioprio || sqe->len || sqe->buf_index) |
| return -EINVAL; |
| |
| addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr); |
| addr_len = (int __user *) (unsigned long) READ_ONCE(sqe->addr2); |
| flags = READ_ONCE(sqe->accept_flags); |
| file_flags = force_nonblock ? O_NONBLOCK : 0; |
| |
| ret = __sys_accept4_file(req->file, file_flags, addr, addr_len, flags); |
| if (ret == -EAGAIN && force_nonblock) { |
| req->work.flags |= IO_WQ_WORK_NEEDS_FILES; |
| return -EAGAIN; |
| } |
| if (ret == -ERESTARTSYS) |
| ret = -EINTR; |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_cqring_add_event(req, ret); |
| io_put_req_find_next(req, nxt); |
| return 0; |
| #else |
| return -EOPNOTSUPP; |
| #endif |
| } |
| |
| static int io_connect_prep(struct io_kiocb *req, struct io_async_ctx *io) |
| { |
| #if defined(CONFIG_NET) |
| const struct io_uring_sqe *sqe = req->sqe; |
| struct sockaddr __user *addr; |
| int addr_len; |
| |
| addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr); |
| addr_len = READ_ONCE(sqe->addr2); |
| return move_addr_to_kernel(addr, addr_len, &io->connect.address); |
| #else |
| return 0; |
| #endif |
| } |
| |
| static int io_connect(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt, bool force_nonblock) |
| { |
| #if defined(CONFIG_NET) |
| struct io_async_ctx __io, *io; |
| unsigned file_flags; |
| int addr_len, ret; |
| |
| if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) |
| return -EINVAL; |
| if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags) |
| return -EINVAL; |
| |
| addr_len = READ_ONCE(sqe->addr2); |
| file_flags = force_nonblock ? O_NONBLOCK : 0; |
| |
| if (req->io) { |
| io = req->io; |
| } else { |
| ret = io_connect_prep(req, &__io); |
| if (ret) |
| goto out; |
| io = &__io; |
| } |
| |
| ret = __sys_connect_file(req->file, &io->connect.address, addr_len, |
| file_flags); |
| if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) { |
| io = kmalloc(sizeof(*io), GFP_KERNEL); |
| if (!io) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| memcpy(&io->connect, &__io.connect, sizeof(io->connect)); |
| req->io = io; |
| memcpy(&io->sqe, req->sqe, sizeof(*req->sqe)); |
| req->sqe = &io->sqe; |
| return -EAGAIN; |
| } |
| if (ret == -ERESTARTSYS) |
| ret = -EINTR; |
| out: |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_cqring_add_event(req, ret); |
| io_put_req_find_next(req, nxt); |
| return 0; |
| #else |
| return -EOPNOTSUPP; |
| #endif |
| } |
| |
| static void io_poll_remove_one(struct io_kiocb *req) |
| { |
| struct io_poll_iocb *poll = &req->poll; |
| |
| spin_lock(&poll->head->lock); |
| WRITE_ONCE(poll->canceled, true); |
| if (!list_empty(&poll->wait.entry)) { |
| list_del_init(&poll->wait.entry); |
| io_queue_async_work(req); |
| } |
| spin_unlock(&poll->head->lock); |
| hash_del(&req->hash_node); |
| } |
| |
| static void io_poll_remove_all(struct io_ring_ctx *ctx) |
| { |
| struct hlist_node *tmp; |
| struct io_kiocb *req; |
| int i; |
| |
| spin_lock_irq(&ctx->completion_lock); |
| for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { |
| struct hlist_head *list; |
| |
| list = &ctx->cancel_hash[i]; |
| hlist_for_each_entry_safe(req, tmp, list, hash_node) |
| io_poll_remove_one(req); |
| } |
| spin_unlock_irq(&ctx->completion_lock); |
| } |
| |
| static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr) |
| { |
| struct hlist_head *list; |
| struct io_kiocb *req; |
| |
| list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)]; |
| hlist_for_each_entry(req, list, hash_node) { |
| if (sqe_addr == req->user_data) { |
| io_poll_remove_one(req); |
| return 0; |
| } |
| } |
| |
| return -ENOENT; |
| } |
| |
| /* |
| * Find a running poll command that matches one specified in sqe->addr, |
| * and remove it if found. |
| */ |
| static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| int ret; |
| |
| if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || |
| sqe->poll_events) |
| return -EINVAL; |
| |
| spin_lock_irq(&ctx->completion_lock); |
| ret = io_poll_cancel(ctx, READ_ONCE(sqe->addr)); |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| io_cqring_add_event(req, ret); |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_put_req(req); |
| return 0; |
| } |
| |
| static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| req->poll.done = true; |
| if (error) |
| io_cqring_fill_event(req, error); |
| else |
| io_cqring_fill_event(req, mangle_poll(mask)); |
| io_commit_cqring(ctx); |
| } |
| |
| static void io_poll_complete_work(struct io_wq_work **workptr) |
| { |
| struct io_wq_work *work = *workptr; |
| struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
| struct io_poll_iocb *poll = &req->poll; |
| struct poll_table_struct pt = { ._key = poll->events }; |
| struct io_ring_ctx *ctx = req->ctx; |
| struct io_kiocb *nxt = NULL; |
| __poll_t mask = 0; |
| int ret = 0; |
| |
| if (work->flags & IO_WQ_WORK_CANCEL) { |
| WRITE_ONCE(poll->canceled, true); |
| ret = -ECANCELED; |
| } else if (READ_ONCE(poll->canceled)) { |
| ret = -ECANCELED; |
| } |
| |
| if (ret != -ECANCELED) |
| mask = vfs_poll(poll->file, &pt) & poll->events; |
| |
| /* |
| * Note that ->ki_cancel callers also delete iocb from active_reqs after |
| * calling ->ki_cancel. We need the ctx_lock roundtrip here to |
| * synchronize with them. In the cancellation case the list_del_init |
| * itself is not actually needed, but harmless so we keep it in to |
| * avoid further branches in the fast path. |
| */ |
| spin_lock_irq(&ctx->completion_lock); |
| if (!mask && ret != -ECANCELED) { |
| add_wait_queue(poll->head, &poll->wait); |
| spin_unlock_irq(&ctx->completion_lock); |
| return; |
| } |
| hash_del(&req->hash_node); |
| io_poll_complete(req, mask, ret); |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| io_cqring_ev_posted(ctx); |
| |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_put_req_find_next(req, &nxt); |
| if (nxt) |
| *workptr = &nxt->work; |
| } |
| |
| static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, |
| void *key) |
| { |
| struct io_poll_iocb *poll = wait->private; |
| struct io_kiocb *req = container_of(poll, struct io_kiocb, poll); |
| struct io_ring_ctx *ctx = req->ctx; |
| __poll_t mask = key_to_poll(key); |
| unsigned long flags; |
| |
| /* for instances that support it check for an event match first: */ |
| if (mask && !(mask & poll->events)) |
| return 0; |
| |
| list_del_init(&poll->wait.entry); |
| |
| /* |
| * Run completion inline if we can. We're using trylock here because |
| * we are violating the completion_lock -> poll wq lock ordering. |
| * If we have a link timeout we're going to need the completion_lock |
| * for finalizing the request, mark us as having grabbed that already. |
| */ |
| if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) { |
| hash_del(&req->hash_node); |
| io_poll_complete(req, mask, 0); |
| req->flags |= REQ_F_COMP_LOCKED; |
| io_put_req(req); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| |
| io_cqring_ev_posted(ctx); |
| } else { |
| io_queue_async_work(req); |
| } |
| |
| return 1; |
| } |
| |
| struct io_poll_table { |
| struct poll_table_struct pt; |
| struct io_kiocb *req; |
| int error; |
| }; |
| |
| static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, |
| struct poll_table_struct *p) |
| { |
| struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); |
| |
| if (unlikely(pt->req->poll.head)) { |
| pt->error = -EINVAL; |
| return; |
| } |
| |
| pt->error = 0; |
| pt->req->poll.head = head; |
| add_wait_queue(head, &pt->req->poll.wait); |
| } |
| |
| static void io_poll_req_insert(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| struct hlist_head *list; |
| |
| list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)]; |
| hlist_add_head(&req->hash_node, list); |
| } |
| |
| static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt) |
| { |
| struct io_poll_iocb *poll = &req->poll; |
| struct io_ring_ctx *ctx = req->ctx; |
| struct io_poll_table ipt; |
| bool cancel = false; |
| __poll_t mask; |
| u16 events; |
| |
| if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index) |
| return -EINVAL; |
| if (!poll->file) |
| return -EBADF; |
| |
| req->io = NULL; |
| INIT_IO_WORK(&req->work, io_poll_complete_work); |
| events = READ_ONCE(sqe->poll_events); |
| poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP; |
| INIT_HLIST_NODE(&req->hash_node); |
| |
| poll->head = NULL; |
| poll->done = false; |
| poll->canceled = false; |
| |
| ipt.pt._qproc = io_poll_queue_proc; |
| ipt.pt._key = poll->events; |
| ipt.req = req; |
| ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ |
| |
| /* initialized the list so that we can do list_empty checks */ |
| INIT_LIST_HEAD(&poll->wait.entry); |
| init_waitqueue_func_entry(&poll->wait, io_poll_wake); |
| poll->wait.private = poll; |
| |
| INIT_LIST_HEAD(&req->list); |
| |
| mask = vfs_poll(poll->file, &ipt.pt) & poll->events; |
| |
| spin_lock_irq(&ctx->completion_lock); |
| if (likely(poll->head)) { |
| spin_lock(&poll->head->lock); |
| if (unlikely(list_empty(&poll->wait.entry))) { |
| if (ipt.error) |
| cancel = true; |
| ipt.error = 0; |
| mask = 0; |
| } |
| if (mask || ipt.error) |
| list_del_init(&poll->wait.entry); |
| else if (cancel) |
| WRITE_ONCE(poll->canceled, true); |
| else if (!poll->done) /* actually waiting for an event */ |
| io_poll_req_insert(req); |
| spin_unlock(&poll->head->lock); |
| } |
| if (mask) { /* no async, we'd stolen it */ |
| ipt.error = 0; |
| io_poll_complete(req, mask, 0); |
| } |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| if (mask) { |
| io_cqring_ev_posted(ctx); |
| io_put_req_find_next(req, nxt); |
| } |
| return ipt.error; |
| } |
| |
| static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) |
| { |
| struct io_timeout_data *data = container_of(timer, |
| struct io_timeout_data, timer); |
| struct io_kiocb *req = data->req; |
| struct io_ring_ctx *ctx = req->ctx; |
| unsigned long flags; |
| |
| atomic_inc(&ctx->cq_timeouts); |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| /* |
| * We could be racing with timeout deletion. If the list is empty, |
| * then timeout lookup already found it and will be handling it. |
| */ |
| if (!list_empty(&req->list)) { |
| struct io_kiocb *prev; |
| |
| /* |
| * Adjust the reqs sequence before the current one because it |
| * will consume a slot in the cq_ring and the cq_tail |
| * pointer will be increased, otherwise other timeout reqs may |
| * return in advance without waiting for enough wait_nr. |
| */ |
| prev = req; |
| list_for_each_entry_continue_reverse(prev, &ctx->timeout_list, list) |
| prev->sequence++; |
| list_del_init(&req->list); |
| } |
| |
| io_cqring_fill_event(req, -ETIME); |
| io_commit_cqring(ctx); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| |
| io_cqring_ev_posted(ctx); |
| req_set_fail_links(req); |
| io_put_req(req); |
| return HRTIMER_NORESTART; |
| } |
| |
| static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data) |
| { |
| struct io_kiocb *req; |
| int ret = -ENOENT; |
| |
| list_for_each_entry(req, &ctx->timeout_list, list) { |
| if (user_data == req->user_data) { |
| list_del_init(&req->list); |
| ret = 0; |
| break; |
| } |
| } |
| |
| if (ret == -ENOENT) |
| return ret; |
| |
| ret = hrtimer_try_to_cancel(&req->io->timeout.timer); |
| if (ret == -1) |
| return -EALREADY; |
| |
| req_set_fail_links(req); |
| io_cqring_fill_event(req, -ECANCELED); |
| io_put_req(req); |
| return 0; |
| } |
| |
| /* |
| * Remove or update an existing timeout command |
| */ |
| static int io_timeout_remove(struct io_kiocb *req, |
| const struct io_uring_sqe *sqe) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| unsigned flags; |
| int ret; |
| |
| if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (sqe->flags || sqe->ioprio || sqe->buf_index || sqe->len) |
| return -EINVAL; |
| flags = READ_ONCE(sqe->timeout_flags); |
| if (flags) |
| return -EINVAL; |
| |
| spin_lock_irq(&ctx->completion_lock); |
| ret = io_timeout_cancel(ctx, READ_ONCE(sqe->addr)); |
| |
| io_cqring_fill_event(req, ret); |
| io_commit_cqring(ctx); |
| spin_unlock_irq(&ctx->completion_lock); |
| io_cqring_ev_posted(ctx); |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_put_req(req); |
| return 0; |
| } |
| |
| static int io_timeout_prep(struct io_kiocb *req, struct io_async_ctx *io, |
| bool is_timeout_link) |
| { |
| const struct io_uring_sqe *sqe = req->sqe; |
| struct io_timeout_data *data; |
| unsigned flags; |
| |
| if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (sqe->ioprio || sqe->buf_index || sqe->len != 1) |
| return -EINVAL; |
| if (sqe->off && is_timeout_link) |
| return -EINVAL; |
| flags = READ_ONCE(sqe->timeout_flags); |
| if (flags & ~IORING_TIMEOUT_ABS) |
| return -EINVAL; |
| |
| data = &io->timeout; |
| data->req = req; |
| req->flags |= REQ_F_TIMEOUT; |
| |
| if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr))) |
| return -EFAULT; |
| |
| if (flags & IORING_TIMEOUT_ABS) |
| data->mode = HRTIMER_MODE_ABS; |
| else |
| data->mode = HRTIMER_MODE_REL; |
| |
| hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode); |
| req->io = io; |
| return 0; |
| } |
| |
| static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
| { |
| unsigned count; |
| struct io_ring_ctx *ctx = req->ctx; |
| struct io_timeout_data *data; |
| struct io_async_ctx *io; |
| struct list_head *entry; |
| unsigned span = 0; |
| |
| io = req->io; |
| if (!io) { |
| int ret; |
| |
| io = kmalloc(sizeof(*io), GFP_KERNEL); |
| if (!io) |
| return -ENOMEM; |
| ret = io_timeout_prep(req, io, false); |
| if (ret) { |
| kfree(io); |
| return ret; |
| } |
| } |
| data = &req->io->timeout; |
| |
| /* |
| * sqe->off holds how many events that need to occur for this |
| * timeout event to be satisfied. If it isn't set, then this is |
| * a pure timeout request, sequence isn't used. |
| */ |
| count = READ_ONCE(sqe->off); |
| if (!count) { |
| req->flags |= REQ_F_TIMEOUT_NOSEQ; |
| spin_lock_irq(&ctx->completion_lock); |
| entry = ctx->timeout_list.prev; |
| goto add; |
| } |
| |
| req->sequence = ctx->cached_sq_head + count - 1; |
| data->seq_offset = count; |
| |
| /* |
| * Insertion sort, ensuring the first entry in the list is always |
| * the one we need first. |
| */ |
| spin_lock_irq(&ctx->completion_lock); |
| list_for_each_prev(entry, &ctx->timeout_list) { |
| struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, list); |
| unsigned nxt_sq_head; |
| long long tmp, tmp_nxt; |
| u32 nxt_offset = nxt->io->timeout.seq_offset; |
| |
| if (nxt->flags & REQ_F_TIMEOUT_NOSEQ) |
| continue; |
| |
| /* |
| * Since cached_sq_head + count - 1 can overflow, use type long |
| * long to store it. |
| */ |
| tmp = (long long)ctx->cached_sq_head + count - 1; |
| nxt_sq_head = nxt->sequence - nxt_offset + 1; |
| tmp_nxt = (long long)nxt_sq_head + nxt_offset - 1; |
| |
| /* |
| * cached_sq_head may overflow, and it will never overflow twice |
| * once there is some timeout req still be valid. |
| */ |
| if (ctx->cached_sq_head < nxt_sq_head) |
| tmp += UINT_MAX; |
| |
| if (tmp > tmp_nxt) |
| break; |
| |
| /* |
| * Sequence of reqs after the insert one and itself should |
| * be adjusted because each timeout req consumes a slot. |
| */ |
| span++; |
| nxt->sequence++; |
| } |
| req->sequence -= span; |
| add: |
| list_add(&req->list, entry); |
| data->timer.function = io_timeout_fn; |
| hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); |
| spin_unlock_irq(&ctx->completion_lock); |
| return 0; |
| } |
| |
| static bool io_cancel_cb(struct io_wq_work *work, void *data) |
| { |
| struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
| |
| return req->user_data == (unsigned long) data; |
| } |
| |
| static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr) |
| { |
| enum io_wq_cancel cancel_ret; |
| int ret = 0; |
| |
| cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr); |
| switch (cancel_ret) { |
| case IO_WQ_CANCEL_OK: |
| ret = 0; |
| break; |
| case IO_WQ_CANCEL_RUNNING: |
| ret = -EALREADY; |
| break; |
| case IO_WQ_CANCEL_NOTFOUND: |
| ret = -ENOENT; |
| break; |
| } |
| |
| return ret; |
| } |
| |
| static void io_async_find_and_cancel(struct io_ring_ctx *ctx, |
| struct io_kiocb *req, __u64 sqe_addr, |
| struct io_kiocb **nxt, int success_ret) |
| { |
| unsigned long flags; |
| int ret; |
| |
| ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr); |
| if (ret != -ENOENT) { |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| goto done; |
| } |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| ret = io_timeout_cancel(ctx, sqe_addr); |
| if (ret != -ENOENT) |
| goto done; |
| ret = io_poll_cancel(ctx, sqe_addr); |
| done: |
| if (!ret) |
| ret = success_ret; |
| io_cqring_fill_event(req, ret); |
| io_commit_cqring(ctx); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| io_cqring_ev_posted(ctx); |
| |
| if (ret < 0) |
| req_set_fail_links(req); |
| io_put_req_find_next(req, nxt); |
| } |
| |
| static int io_async_cancel(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| struct io_kiocb **nxt) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (sqe->flags || sqe->ioprio || sqe->off || sqe->len || |
| sqe->cancel_flags) |
| return -EINVAL; |
| |
| io_async_find_and_cancel(ctx, req, READ_ONCE(sqe->addr), nxt, 0); |
| return 0; |
| } |
| |
| static int io_req_defer_prep(struct io_kiocb *req, struct io_async_ctx *io) |
| { |
| struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; |
| struct iov_iter iter; |
| ssize_t ret; |
| |
| memcpy(&io->sqe, req->sqe, sizeof(io->sqe)); |
| req->sqe = &io->sqe; |
| |
| switch (io->sqe.opcode) { |
| case IORING_OP_READV: |
| case IORING_OP_READ_FIXED: |
| ret = io_read_prep(req, &iovec, &iter, true); |
| break; |
| case IORING_OP_WRITEV: |
| case IORING_OP_WRITE_FIXED: |
| ret = io_write_prep(req, &iovec, &iter, true); |
| break; |
| case IORING_OP_SENDMSG: |
| ret = io_sendmsg_prep(req, io); |
| break; |
| case IORING_OP_RECVMSG: |
| ret = io_recvmsg_prep(req, io); |
| break; |
| case IORING_OP_CONNECT: |
| ret = io_connect_prep(req, io); |
| break; |
| case IORING_OP_TIMEOUT: |
| return io_timeout_prep(req, io, false); |
| case IORING_OP_LINK_TIMEOUT: |
| return io_timeout_prep(req, io, true); |
| default: |
| req->io = io; |
| return 0; |
| } |
| |
| if (ret < 0) |
| return ret; |
| |
| req->io = io; |
| io_req_map_io(req, ret, iovec, inline_vecs, &iter); |
| return 0; |
| } |
| |
| static int io_req_defer(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| struct io_async_ctx *io; |
| int ret; |
| |
| /* Still need defer if there is pending req in defer list. */ |
| if (!req_need_defer(req) && list_empty(&ctx->defer_list)) |
| return 0; |
| |
| io = kmalloc(sizeof(*io), GFP_KERNEL); |
| if (!io) |
| return -EAGAIN; |
| |
| ret = io_req_defer_prep(req, io); |
| if (ret < 0) { |
| kfree(io); |
| return ret; |
| } |
| |
| spin_lock_irq(&ctx->completion_lock); |
| if (!req_need_defer(req) && list_empty(&ctx->defer_list)) { |
| spin_unlock_irq(&ctx->completion_lock); |
| return 0; |
| } |
| |
| trace_io_uring_defer(ctx, req, req->user_data); |
| list_add_tail(&req->list, &ctx->defer_list); |
| spin_unlock_irq(&ctx->completion_lock); |
| return -EIOCBQUEUED; |
| } |
| |
| __attribute__((nonnull)) |
| static int io_issue_sqe(struct io_kiocb *req, struct io_kiocb **nxt, |
| bool force_nonblock) |
| { |
| int ret, opcode; |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| opcode = READ_ONCE(req->sqe->opcode); |
| switch (opcode) { |
| case IORING_OP_NOP: |
| ret = io_nop(req); |
| break; |
| case IORING_OP_READV: |
| if (unlikely(req->sqe->buf_index)) |
| return -EINVAL; |
| ret = io_read(req, nxt, force_nonblock); |
| break; |
| case IORING_OP_WRITEV: |
| if (unlikely(req->sqe->buf_index)) |
| return -EINVAL; |
| ret = io_write(req, nxt, force_nonblock); |
| break; |
| case IORING_OP_READ_FIXED: |
| ret = io_read(req, nxt, force_nonblock); |
| break; |
| case IORING_OP_WRITE_FIXED: |
| ret = io_write(req, nxt, force_nonblock); |
| break; |
| case IORING_OP_FSYNC: |
| ret = io_fsync(req, req->sqe, nxt, force_nonblock); |
| break; |
| case IORING_OP_POLL_ADD: |
| ret = io_poll_add(req, req->sqe, nxt); |
| break; |
| case IORING_OP_POLL_REMOVE: |
| ret = io_poll_remove(req, req->sqe); |
| break; |
| case IORING_OP_SYNC_FILE_RANGE: |
| ret = io_sync_file_range(req, req->sqe, nxt, force_nonblock); |
| break; |
| case IORING_OP_SENDMSG: |
| ret = io_sendmsg(req, req->sqe, nxt, force_nonblock); |
| break; |
| case IORING_OP_RECVMSG: |
| ret = io_recvmsg(req, req->sqe, nxt, force_nonblock); |
| break; |
| case IORING_OP_TIMEOUT: |
| ret = io_timeout(req, req->sqe); |
| break; |
| case IORING_OP_TIMEOUT_REMOVE: |
| ret = io_timeout_remove(req, req->sqe); |
| break; |
| case IORING_OP_ACCEPT: |
| ret = io_accept(req, req->sqe, nxt, force_nonblock); |
| break; |
| case IORING_OP_CONNECT: |
| ret = io_connect(req, req->sqe, nxt, force_nonblock); |
| break; |
| case IORING_OP_ASYNC_CANCEL: |
| ret = io_async_cancel(req, req->sqe, nxt); |
| break; |
| default: |
| ret = -EINVAL; |
| break; |
| } |
| |
| if (ret) |
| return ret; |
| |
| if (ctx->flags & IORING_SETUP_IOPOLL) { |
| if (req->result == -EAGAIN) |
| return -EAGAIN; |
| |
| io_iopoll_req_issued(req); |
| } |
| |
| return 0; |
| } |
| |
| static void io_link_work_cb(struct io_wq_work **workptr) |
| { |
| struct io_wq_work *work = *workptr; |
| struct io_kiocb *link = work->data; |
| |
| io_queue_linked_timeout(link); |
| work->func = io_wq_submit_work; |
| } |
| |
| static void io_wq_submit_work(struct io_wq_work **workptr) |
| { |
| struct io_wq_work *work = *workptr; |
| struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
| struct io_kiocb *nxt = NULL; |
| int ret = 0; |
| |
| /* Ensure we clear previously set non-block flag */ |
| req->rw.ki_flags &= ~IOCB_NOWAIT; |
| |
| if (work->flags & IO_WQ_WORK_CANCEL) |
| ret = -ECANCELED; |
| |
| if (!ret) { |
| req->has_user = (work->flags & IO_WQ_WORK_HAS_MM) != 0; |
| req->in_async = true; |
| do { |
| ret = io_issue_sqe(req, &nxt, false); |
| /* |
| * We can get EAGAIN for polled IO even though we're |
| * forcing a sync submission from here, since we can't |
| * wait for request slots on the block side. |
| */ |
| if (ret != -EAGAIN) |
| break; |
| cond_resched(); |
| } while (1); |
| } |
| |
| /* drop submission reference */ |
| io_put_req(req); |
| |
| if (ret) { |
| req_set_fail_links(req); |
| io_cqring_add_event(req, ret); |
| io_put_req(req); |
| } |
| |
| /* if a dependent link is ready, pass it back */ |
| if (!ret && nxt) { |
| struct io_kiocb *link; |
| |
| io_prep_async_work(nxt, &link); |
| *workptr = &nxt->work; |
| if (link) { |
| nxt->work.flags |= IO_WQ_WORK_CB; |
| nxt->work.func = io_link_work_cb; |
| nxt->work.data = link; |
| } |
| } |
| } |
| |
| static bool io_req_op_valid(int op) |
| { |
| return op >= IORING_OP_NOP && op < IORING_OP_LAST; |
| } |
| |
| static int io_op_needs_file(const struct io_uring_sqe *sqe) |
| { |
| int op = READ_ONCE(sqe->opcode); |
| |
| switch (op) { |
| case IORING_OP_NOP: |
| case IORING_OP_POLL_REMOVE: |
| case IORING_OP_TIMEOUT: |
| case IORING_OP_TIMEOUT_REMOVE: |
| case IORING_OP_ASYNC_CANCEL: |
| case IORING_OP_LINK_TIMEOUT: |
| return 0; |
| default: |
| if (io_req_op_valid(op)) |
| return 1; |
| return -EINVAL; |
| } |
| } |
| |
| static inline struct file *io_file_from_index(struct io_ring_ctx *ctx, |
| int index) |
| { |
| struct fixed_file_table *table; |
| |
| table = &ctx->file_table[index >> IORING_FILE_TABLE_SHIFT]; |
| return table->files[index & IORING_FILE_TABLE_MASK]; |
| } |
| |
| static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| unsigned flags; |
| int fd, ret; |
| |
| flags = READ_ONCE(req->sqe->flags); |
| fd = READ_ONCE(req->sqe->fd); |
| |
| if (flags & IOSQE_IO_DRAIN) |
| req->flags |= REQ_F_IO_DRAIN; |
| |
| ret = io_op_needs_file(req->sqe); |
| if (ret <= 0) |
| return ret; |
| |
| if (flags & IOSQE_FIXED_FILE) { |
| if (unlikely(!ctx->file_table || |
| (unsigned) fd >= ctx->nr_user_files)) |
| return -EBADF; |
| fd = array_index_nospec(fd, ctx->nr_user_files); |
| req->file = io_file_from_index(ctx, fd); |
| if (!req->file) |
| return -EBADF; |
| req->flags |= REQ_F_FIXED_FILE; |
| } else { |
| if (req->needs_fixed_file) |
| return -EBADF; |
| trace_io_uring_file_get(ctx, fd); |
| req->file = io_file_get(state, fd); |
| if (unlikely(!req->file)) |
| return -EBADF; |
| } |
| |
| return 0; |
| } |
| |
| static int io_grab_files(struct io_kiocb *req) |
| { |
| int ret = -EBADF; |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| rcu_read_lock(); |
| spin_lock_irq(&ctx->inflight_lock); |
| /* |
| * We use the f_ops->flush() handler to ensure that we can flush |
| * out work accessing these files if the fd is closed. Check if |
| * the fd has changed since we started down this path, and disallow |
| * this operation if it has. |
| */ |
| if (fcheck(req->ring_fd) == req->ring_file) { |
| list_add(&req->inflight_entry, &ctx->inflight_list); |
| req->flags |= REQ_F_INFLIGHT; |
| req->work.files = current->files; |
| ret = 0; |
| } |
| spin_unlock_irq(&ctx->inflight_lock); |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| |
| static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) |
| { |
| struct io_timeout_data *data = container_of(timer, |
| struct io_timeout_data, timer); |
| struct io_kiocb *req = data->req; |
| struct io_ring_ctx *ctx = req->ctx; |
| struct io_kiocb *prev = NULL; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| |
| /* |
| * We don't expect the list to be empty, that will only happen if we |
| * race with the completion of the linked work. |
| */ |
| if (!list_empty(&req->link_list)) { |
| prev = list_entry(req->link_list.prev, struct io_kiocb, |
| link_list); |
| if (refcount_inc_not_zero(&prev->refs)) { |
| list_del_init(&req->link_list); |
| prev->flags &= ~REQ_F_LINK_TIMEOUT; |
| } else |
| prev = NULL; |
| } |
| |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| |
| if (prev) { |
| req_set_fail_links(prev); |
| io_async_find_and_cancel(ctx, req, prev->user_data, NULL, |
| -ETIME); |
| io_put_req(prev); |
| } else { |
| io_cqring_add_event(req, -ETIME); |
| io_put_req(req); |
| } |
| return HRTIMER_NORESTART; |
| } |
| |
| static void io_queue_linked_timeout(struct io_kiocb *req) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| |
| /* |
| * If the list is now empty, then our linked request finished before |
| * we got a chance to setup the timer |
| */ |
| spin_lock_irq(&ctx->completion_lock); |
| if (!list_empty(&req->link_list)) { |
| struct io_timeout_data *data = &req->io->timeout; |
| |
| data->timer.function = io_link_timeout_fn; |
| hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), |
| data->mode); |
| } |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| /* drop submission reference */ |
| io_put_req(req); |
| } |
| |
| static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req) |
| { |
| struct io_kiocb *nxt; |
| |
| if (!(req->flags & REQ_F_LINK)) |
| return NULL; |
| |
| nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, |
| link_list); |
| if (!nxt || nxt->sqe->opcode != IORING_OP_LINK_TIMEOUT) |
| return NULL; |
| |
| req->flags |= REQ_F_LINK_TIMEOUT; |
| return nxt; |
| } |
| |
| static void __io_queue_sqe(struct io_kiocb *req) |
| { |
| struct io_kiocb *linked_timeout; |
| struct io_kiocb *nxt = NULL; |
| int ret; |
| |
| again: |
| linked_timeout = io_prep_linked_timeout(req); |
| |
| ret = io_issue_sqe(req, &nxt, true); |
| |
| /* |
| * We async punt it if the file wasn't marked NOWAIT, or if the file |
| * doesn't support non-blocking read/write attempts |
| */ |
| if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) || |
| (req->flags & REQ_F_MUST_PUNT))) { |
| if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) { |
| ret = io_grab_files(req); |
| if (ret) |
| goto err; |
| } |
| |
| /* |
| * Queued up for async execution, worker will release |
| * submit reference when the iocb is actually submitted. |
| */ |
| io_queue_async_work(req); |
| goto done_req; |
| } |
| |
| err: |
| /* drop submission reference */ |
| io_put_req(req); |
| |
| if (linked_timeout) { |
| if (!ret) |
| io_queue_linked_timeout(linked_timeout); |
| else |
| io_put_req(linked_timeout); |
| } |
| |
| /* and drop final reference, if we failed */ |
| if (ret) { |
| io_cqring_add_event(req, ret); |
| req_set_fail_links(req); |
| io_put_req(req); |
| } |
| done_req: |
| if (nxt) { |
| req = nxt; |
| nxt = NULL; |
| goto again; |
| } |
| } |
| |
| static void io_queue_sqe(struct io_kiocb *req) |
| { |
| int ret; |
| |
| if (unlikely(req->ctx->drain_next)) { |
| req->flags |= REQ_F_IO_DRAIN; |
| req->ctx->drain_next = false; |
| } |
| req->ctx->drain_next = (req->flags & REQ_F_DRAIN_LINK); |
| |
| ret = io_req_defer(req); |
| if (ret) { |
| if (ret != -EIOCBQUEUED) { |
| io_cqring_add_event(req, ret); |
| req_set_fail_links(req); |
| io_double_put_req(req); |
| } |
| } else |
| __io_queue_sqe(req); |
| } |
| |
| static inline void io_queue_link_head(struct io_kiocb *req) |
| { |
| if (unlikely(req->flags & REQ_F_FAIL_LINK)) { |
| io_cqring_add_event(req, -ECANCELED); |
| io_double_put_req(req); |
| } else |
| io_queue_sqe(req); |
| } |
| |
| #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \ |
| IOSQE_IO_HARDLINK) |
| |
| static bool io_submit_sqe(struct io_kiocb *req, struct io_submit_state *state, |
| struct io_kiocb **link) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| int ret; |
| |
| req->user_data = req->sqe->user_data; |
| |
| /* enforce forwards compatibility on users */ |
| if (unlikely(req->sqe->flags & ~SQE_VALID_FLAGS)) { |
| ret = -EINVAL; |
| goto err_req; |
| } |
| |
| ret = io_req_set_file(state, req); |
| if (unlikely(ret)) { |
| err_req: |
| io_cqring_add_event(req, ret); |
| io_double_put_req(req); |
| return false; |
| } |
| |
| /* |
| * If we already have a head request, queue this one for async |
| * submittal once the head completes. If we don't have a head but |
| * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be |
| * submitted sync once the chain is complete. If none of those |
| * conditions are true (normal request), then just queue it. |
| */ |
| if (*link) { |
| struct io_kiocb *prev = *link; |
| struct io_async_ctx *io; |
| |
| if (req->sqe->flags & IOSQE_IO_DRAIN) |
| (*link)->flags |= REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN; |
| |
| if (req->sqe->flags & IOSQE_IO_HARDLINK) |
| req->flags |= REQ_F_HARDLINK; |
| |
| io = kmalloc(sizeof(*io), GFP_KERNEL); |
| if (!io) { |
| ret = -EAGAIN; |
| goto err_req; |
| } |
| |
| ret = io_req_defer_prep(req, io); |
| if (ret) { |
| kfree(io); |
| /* fail even hard links since we don't submit */ |
| prev->flags |= REQ_F_FAIL_LINK; |
| goto err_req; |
| } |
| trace_io_uring_link(ctx, req, prev); |
| list_add_tail(&req->link_list, &prev->link_list); |
| } else if (req->sqe->flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) { |
| req->flags |= REQ_F_LINK; |
| if (req->sqe->flags & IOSQE_IO_HARDLINK) |
| req->flags |= REQ_F_HARDLINK; |
| |
| INIT_LIST_HEAD(&req->link_list); |
| *link = req; |
| } else { |
| io_queue_sqe(req); |
| } |
| |
| return true; |
| } |
| |
| /* |
| * Batched submission is done, ensure local IO is flushed out. |
| */ |
| static void io_submit_state_end(struct io_submit_state *state) |
| { |
| blk_finish_plug(&state->plug); |
| io_file_put(state); |
| if (state->free_reqs) |
| kmem_cache_free_bulk(req_cachep, state->free_reqs, |
| &state->reqs[state->cur_req]); |
| } |
| |
| /* |
| * Start submission side cache. |
| */ |
| static void io_submit_state_start(struct io_submit_state *state, |
| unsigned int max_ios) |
| { |
| blk_start_plug(&state->plug); |
| state->free_reqs = 0; |
| state->file = NULL; |
| state->ios_left = max_ios; |
| } |
| |
| static void io_commit_sqring(struct io_ring_ctx *ctx) |
| { |
| struct io_rings *rings = ctx->rings; |
| |
| if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) { |
| /* |
| * Ensure any loads from the SQEs are done at this point, |
| * since once we write the new head, the application could |
| * write new data to them. |
| */ |
| smp_store_release(&rings->sq.head, ctx->cached_sq_head); |
| } |
| } |
| |
| /* |
| * Fetch an sqe, if one is available. Note that req->sqe will point to memory |
| * that is mapped by userspace. This means that care needs to be taken to |
| * ensure that reads are stable, as we cannot rely on userspace always |
| * being a good citizen. If members of the sqe are validated and then later |
| * used, it's important that those reads are done through READ_ONCE() to |
| * prevent a re-load down the line. |
| */ |
| static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req) |
| { |
| struct io_rings *rings = ctx->rings; |
| u32 *sq_array = ctx->sq_array; |
| unsigned head; |
| |
| /* |
| * The cached sq head (or cq tail) serves two purposes: |
| * |
| * 1) allows us to batch the cost of updating the user visible |
| * head updates. |
| * 2) allows the kernel side to track the head on its own, even |
| * though the application is the one updating it. |
| */ |
| head = ctx->cached_sq_head; |
| /* make sure SQ entry isn't read before tail */ |
| if (unlikely(head == smp_load_acquire(&rings->sq.tail))) |
| return false; |
| |
| head = READ_ONCE(sq_array[head & ctx->sq_mask]); |
| if (likely(head < ctx->sq_entries)) { |
| /* |
| * All io need record the previous position, if LINK vs DARIN, |
| * it can be used to mark the position of the first IO in the |
| * link list. |
| */ |
| req->sequence = ctx->cached_sq_head; |
| req->sqe = &ctx->sq_sqes[head]; |
| ctx->cached_sq_head++; |
| return true; |
| } |
| |
| /* drop invalid entries */ |
| ctx->cached_sq_head++; |
| ctx->cached_sq_dropped++; |
| WRITE_ONCE(rings->sq_dropped, ctx->cached_sq_dropped); |
| return false; |
| } |
| |
| static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr, |
| struct file *ring_file, int ring_fd, |
| struct mm_struct **mm, bool async) |
| { |
| struct io_submit_state state, *statep = NULL; |
| struct io_kiocb *link = NULL; |
| int i, submitted = 0; |
| bool mm_fault = false; |
| |
| /* if we have a backlog and couldn't flush it all, return BUSY */ |
| if (!list_empty(&ctx->cq_overflow_list) && |
| !io_cqring_overflow_flush(ctx, false)) |
| return -EBUSY; |
| |
| if (nr > IO_PLUG_THRESHOLD) { |
| io_submit_state_start(&state, nr); |
| statep = &state; |
| } |
| |
| for (i = 0; i < nr; i++) { |
| struct io_kiocb *req; |
| unsigned int sqe_flags; |
| |
| req = io_get_req(ctx, statep); |
| if (unlikely(!req)) { |
| if (!submitted) |
| submitted = -EAGAIN; |
| break; |
| } |
| if (!io_get_sqring(ctx, req)) { |
| __io_free_req(req); |
| break; |
| } |
| |
| if (io_sqe_needs_user(req->sqe) && !*mm) { |
| mm_fault = mm_fault || !mmget_not_zero(ctx->sqo_mm); |
| if (!mm_fault) { |
| use_mm(ctx->sqo_mm); |
| *mm = ctx->sqo_mm; |
| } |
| } |
| |
| submitted++; |
| sqe_flags = req->sqe->flags; |
| |
| req->ring_file = ring_file; |
| req->ring_fd = ring_fd; |
| req->has_user = *mm != NULL; |
| req->in_async = async; |
| req->needs_fixed_file = async; |
| trace_io_uring_submit_sqe(ctx, req->sqe->user_data, |
| true, async); |
| if (!io_submit_sqe(req, statep, &link)) |
| break; |
| /* |
| * If previous wasn't linked and we have a linked command, |
| * that's the end of the chain. Submit the previous link. |
| */ |
| if (!(sqe_flags & IOSQE_IO_LINK) && link) { |
| io_queue_link_head(link); |
| link = NULL; |
| } |
| } |
| |
| if (link) |
| io_queue_link_head(link); |
| if (statep) |
| io_submit_state_end(&state); |
| |
| /* Commit SQ ring head once we've consumed and submitted all SQEs */ |
| io_commit_sqring(ctx); |
| |
| return submitted; |
| } |
| |
| static int io_sq_thread(void *data) |
| { |
| struct io_ring_ctx *ctx = data; |
| struct mm_struct *cur_mm = NULL; |
| const struct cred *old_cred; |
| mm_segment_t old_fs; |
| DEFINE_WAIT(wait); |
| unsigned inflight; |
| unsigned long timeout; |
| int ret; |
| |
| complete(&ctx->completions[1]); |
| |
| old_fs = get_fs(); |
| set_fs(USER_DS); |
| old_cred = override_creds(ctx->creds); |
| |
| ret = timeout = inflight = 0; |
| while (!kthread_should_park()) { |
| unsigned int to_submit; |
| |
| if (inflight) { |
| unsigned nr_events = 0; |
| |
| if (ctx->flags & IORING_SETUP_IOPOLL) { |
| /* |
| * inflight is the count of the maximum possible |
| * entries we submitted, but it can be smaller |
| * if we dropped some of them. If we don't have |
| * poll entries available, then we know that we |
| * have nothing left to poll for. Reset the |
| * inflight count to zero in that case. |
| */ |
| mutex_lock(&ctx->uring_lock); |
| if (!list_empty(&ctx->poll_list)) |
| __io_iopoll_check(ctx, &nr_events, 0); |
| else |
| inflight = 0; |
| mutex_unlock(&ctx->uring_lock); |
| } else { |
| /* |
| * Normal IO, just pretend everything completed. |
| * We don't have to poll completions for that. |
| */ |
| nr_events = inflight; |
| } |
| |
| inflight -= nr_events; |
| if (!inflight) |
| timeout = jiffies + ctx->sq_thread_idle; |
| } |
| |
| to_submit = io_sqring_entries(ctx); |
| |
| /* |
| * If submit got -EBUSY, flag us as needing the application |
| * to enter the kernel to reap and flush events. |
| */ |
| if (!to_submit || ret == -EBUSY) { |
| /* |
| * We're polling. If we're within the defined idle |
| * period, then let us spin without work before going |
| * to sleep. The exception is if we got EBUSY doing |
| * more IO, we should wait for the application to |
| * reap events and wake us up. |
| */ |
| if (inflight || |
| (!time_after(jiffies, timeout) && ret != -EBUSY)) { |
| cond_resched(); |
| continue; |
| } |
| |
| /* |
| * Drop cur_mm before scheduling, we can't hold it for |
| * long periods (or over schedule()). Do this before |
| * adding ourselves to the waitqueue, as the unuse/drop |
| * may sleep. |
| */ |
| if (cur_mm) { |
| unuse_mm(cur_mm); |
| mmput(cur_mm); |
| cur_mm = NULL; |
| } |
| |
| prepare_to_wait(&ctx->sqo_wait, &wait, |
| TASK_INTERRUPTIBLE); |
| |
| /* Tell userspace we may need a wakeup call */ |
| ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP; |
| /* make sure to read SQ tail after writing flags */ |
| smp_mb(); |
| |
| to_submit = io_sqring_entries(ctx); |
| if (!to_submit || ret == -EBUSY) { |
| if (kthread_should_park()) { |
| finish_wait(&ctx->sqo_wait, &wait); |
| break; |
| } |
| if (signal_pending(current)) |
| flush_signals(current); |
| schedule(); |
| finish_wait(&ctx->sqo_wait, &wait); |
| |
| ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; |
| continue; |
| } |
| finish_wait(&ctx->sqo_wait, &wait); |
| |
| ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; |
| } |
| |
| to_submit = min(to_submit, ctx->sq_entries); |
| mutex_lock(&ctx->uring_lock); |
| ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true); |
| mutex_unlock(&ctx->uring_lock); |
| if (ret > 0) |
| inflight += ret; |
| } |
| |
| set_fs(old_fs); |
| if (cur_mm) { |
| unuse_mm(cur_mm); |
| mmput(cur_mm); |
| } |
| revert_creds(old_cred); |
| |
| kthread_parkme(); |
| |
| return 0; |
| } |
| |
| struct io_wait_queue { |
| struct wait_queue_entry wq; |
| struct io_ring_ctx *ctx; |
| unsigned to_wait; |
| unsigned nr_timeouts; |
| }; |
| |
| static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush) |
| { |
| struct io_ring_ctx *ctx = iowq->ctx; |
| |
| /* |
| * Wake up if we have enough events, or if a timeout occurred since we |
| * started waiting. For timeouts, we always want to return to userspace, |
| * regardless of event count. |
| */ |
| return io_cqring_events(ctx, noflush) >= iowq->to_wait || |
| atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; |
| } |
| |
| static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode, |
| int wake_flags, void *key) |
| { |
| struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, |
| wq); |
| |
| /* use noflush == true, as we can't safely rely on locking context */ |
| if (!io_should_wake(iowq, true)) |
| return -1; |
| |
| return autoremove_wake_function(curr, mode, wake_flags, key); |
| } |
| |
| /* |
| * Wait until events become available, if we don't already have some. The |
| * application must reap them itself, as they reside on the shared cq ring. |
| */ |
| static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, |
| const sigset_t __user *sig, size_t sigsz) |
| { |
| struct io_wait_queue iowq = { |
| .wq = { |
| .private = current, |
| .func = io_wake_function, |
| .entry = LIST_HEAD_INIT(iowq.wq.entry), |
| }, |
| .ctx = ctx, |
| .to_wait = min_events, |
| }; |
| struct io_rings *rings = ctx->rings; |
| int ret = 0; |
| |
| if (io_cqring_events(ctx, false) >= min_events) |
| return 0; |
| |
| if (sig) { |
| #ifdef CONFIG_COMPAT |
| if (in_compat_syscall()) |
| ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig, |
| sigsz); |
| else |
| #endif |
| ret = set_user_sigmask(sig, sigsz); |
| |
| if (ret) |
| return ret; |
| } |
| |
| iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); |
| trace_io_uring_cqring_wait(ctx, min_events); |
| do { |
| prepare_to_wait_exclusive(&ctx->wait, &iowq.wq, |
| TASK_INTERRUPTIBLE); |
| if (io_should_wake(&iowq, false)) |
| break; |
| schedule(); |
| if (signal_pending(current)) { |
| ret = -EINTR; |
| break; |
| } |
| } while (1); |
| finish_wait(&ctx->wait, &iowq.wq); |
| |
| restore_saved_sigmask_unless(ret == -EINTR); |
| |
| return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0; |
| } |
| |
| static void __io_sqe_files_unregister(struct io_ring_ctx *ctx) |
| { |
| #if defined(CONFIG_UNIX) |
| if (ctx->ring_sock) { |
| struct sock *sock = ctx->ring_sock->sk; |
| struct sk_buff *skb; |
| |
| while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) |
| kfree_skb(skb); |
| } |
| #else |
| int i; |
| |
| for (i = 0; i < ctx->nr_user_files; i++) { |
| struct file *file; |
| |
| file = io_file_from_index(ctx, i); |
| if (file) |
| fput(file); |
| } |
| #endif |
| } |
| |
| static int io_sqe_files_unregister(struct io_ring_ctx *ctx) |
| { |
| unsigned nr_tables, i; |
| |
| if (!ctx->file_table) |
| return -ENXIO; |
| |
| __io_sqe_files_unregister(ctx); |
| nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE); |
| for (i = 0; i < nr_tables; i++) |
| kfree(ctx->file_table[i].files); |
| kfree(ctx->file_table); |
| ctx->file_table = NULL; |
| ctx->nr_user_files = 0; |
| return 0; |
| } |
| |
| static void io_sq_thread_stop(struct io_ring_ctx *ctx) |
| { |
| if (ctx->sqo_thread) { |
| wait_for_completion(&ctx->completions[1]); |
| /* |
| * The park is a bit of a work-around, without it we get |
| * warning spews on shutdown with SQPOLL set and affinity |
| * set to a single CPU. |
| */ |
| kthread_park(ctx->sqo_thread); |
| kthread_stop(ctx->sqo_thread); |
| ctx->sqo_thread = NULL; |
| } |
| } |
| |
| static void io_finish_async(struct io_ring_ctx *ctx) |
| { |
| io_sq_thread_stop(ctx); |
| |
| if (ctx->io_wq) { |
| io_wq_destroy(ctx->io_wq); |
| ctx->io_wq = NULL; |
| } |
| } |
| |
| #if defined(CONFIG_UNIX) |
| static void io_destruct_skb(struct sk_buff *skb) |
| { |
| struct io_ring_ctx *ctx = skb->sk->sk_user_data; |
| |
| if (ctx->io_wq) |
| io_wq_flush(ctx->io_wq); |
| |
| unix_destruct_scm(skb); |
| } |
| |
| /* |
| * Ensure the UNIX gc is aware of our file set, so we are certain that |
| * the io_uring can be safely unregistered on process exit, even if we have |
| * loops in the file referencing. |
| */ |
| static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset) |
| { |
| struct sock *sk = ctx->ring_sock->sk; |
| struct scm_fp_list *fpl; |
| struct sk_buff *skb; |
| int i, nr_files; |
| |
| if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) { |
| unsigned long inflight = ctx->user->unix_inflight + nr; |
| |
| if (inflight > task_rlimit(current, RLIMIT_NOFILE)) |
| return -EMFILE; |
| } |
| |
| fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); |
| if (!fpl) |
| return -ENOMEM; |
| |
| skb = alloc_skb(0, GFP_KERNEL); |
| if (!skb) { |
| kfree(fpl); |
| return -ENOMEM; |
| } |
| |
| skb->sk = sk; |
| |
| nr_files = 0; |
| fpl->user = get_uid(ctx->user); |
| for (i = 0; i < nr; i++) { |
| struct file *file = io_file_from_index(ctx, i + offset); |
| |
| if (!file) |
| continue; |
| fpl->fp[nr_files] = get_file(file); |
| unix_inflight(fpl->user, fpl->fp[nr_files]); |
| nr_files++; |
| } |
| |
| if (nr_files) { |
| fpl->max = SCM_MAX_FD; |
| fpl->count = nr_files; |
| UNIXCB(skb).fp = fpl; |
| skb->destructor = io_destruct_skb; |
| refcount_add(skb->truesize, &sk->sk_wmem_alloc); |
| skb_queue_head(&sk->sk_receive_queue, skb); |
| |
| for (i = 0; i < nr_files; i++) |
| fput(fpl->fp[i]); |
| } else { |
| kfree_skb(skb); |
| kfree(fpl); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * If UNIX sockets are enabled, fd passing can cause a reference cycle which |
| * causes regular reference counting to break down. We rely on the UNIX |
| * garbage collection to take care of this problem for us. |
| */ |
| static int io_sqe_files_scm(struct io_ring_ctx *ctx) |
| { |
| unsigned left, total; |
| int ret = 0; |
| |
| total = 0; |
| left = ctx->nr_user_files; |
| while (left) { |
| unsigned this_files = min_t(unsigned, left, SCM_MAX_FD); |
| |
| ret = __io_sqe_files_scm(ctx, this_files, total); |
| if (ret) |
| break; |
| left -= this_files; |
| total += this_files; |
| } |
| |
| if (!ret) |
| return 0; |
| |
| while (total < ctx->nr_user_files) { |
| struct file *file = io_file_from_index(ctx, total); |
| |
| if (file) |
| fput(file); |
| total++; |
| } |
| |
| return ret; |
| } |
| #else |
| static int io_sqe_files_scm(struct io_ring_ctx *ctx) |
| { |
| return 0; |
| } |
| #endif |
| |
| static int io_sqe_alloc_file_tables(struct io_ring_ctx *ctx, unsigned nr_tables, |
| unsigned nr_files) |
| { |
| int i; |
| |
| for (i = 0; i < nr_tables; i++) { |
| struct fixed_file_table *table = &ctx->file_table[i]; |
| unsigned this_files; |
| |
| this_files = min(nr_files, IORING_MAX_FILES_TABLE); |
| table->files = kcalloc(this_files, sizeof(struct file *), |
| GFP_KERNEL); |
| if (!table->files) |
| break; |
| nr_files -= this_files; |
| } |
| |
| if (i == nr_tables) |
| return 0; |
| |
| for (i = 0; i < nr_tables; i++) { |
| struct fixed_file_table *table = &ctx->file_table[i]; |
| kfree(table->files); |
| } |
| return 1; |
| } |
| |
| static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, |
| unsigned nr_args) |
| { |
| __s32 __user *fds = (__s32 __user *) arg; |
| unsigned nr_tables; |
| int fd, ret = 0; |
| unsigned i; |
| |
| if (ctx->file_table) |
| return -EBUSY; |
| if (!nr_args) |
| return -EINVAL; |
| if (nr_args > IORING_MAX_FIXED_FILES) |
| return -EMFILE; |
| |
| nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE); |
| ctx->file_table = kcalloc(nr_tables, sizeof(struct fixed_file_table), |
| GFP_KERNEL); |
| if (!ctx->file_table) |
| return -ENOMEM; |
| |
| if (io_sqe_alloc_file_tables(ctx, nr_tables, nr_args)) { |
| kfree(ctx->file_table); |
| ctx->file_table = NULL; |
| return -ENOMEM; |
| } |
| |
| for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { |
| struct fixed_file_table *table; |
| unsigned index; |
| |
| ret = -EFAULT; |
| if (copy_from_user(&fd, &fds[i], sizeof(fd))) |
| break; |
| /* allow sparse sets */ |
| if (fd == -1) { |
| ret = 0; |
| continue; |
| } |
| |
| table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT]; |
| index = i & IORING_FILE_TABLE_MASK; |
| table->files[index] = fget(fd); |
| |
| ret = -EBADF; |
| if (!table->files[index]) |
| break; |
| /* |
| * Don't allow io_uring instances to be registered. If UNIX |
| * isn't enabled, then this causes a reference cycle and this |
| * instance can never get freed. If UNIX is enabled we'll |
| * handle it just fine, but there's still no point in allowing |
| * a ring fd as it doesn't support regular read/write anyway. |
| */ |
| if (table->files[index]->f_op == &io_uring_fops) { |
| fput(table->files[index]); |
| break; |
| } |
| ret = 0; |
| } |
| |
| if (ret) { |
| for (i = 0; i < ctx->nr_user_files; i++) { |
| struct file *file; |
| |
| file = io_file_from_index(ctx, i); |
| if (file) |
| fput(file); |
| } |
| for (i = 0; i < nr_tables; i++) |
| kfree(ctx->file_table[i].files); |
| |
| kfree(ctx->file_table); |
| ctx->file_table = NULL; |
| ctx->nr_user_files = 0; |
| return ret; |
| } |
| |
| ret = io_sqe_files_scm(ctx); |
| if (ret) |
| io_sqe_files_unregister(ctx); |
| |
| return ret; |
| } |
| |
| static void io_sqe_file_unregister(struct io_ring_ctx *ctx, int index) |
| { |
| #if defined(CONFIG_UNIX) |
| struct file *file = io_file_from_index(ctx, index); |
| struct sock *sock = ctx->ring_sock->sk; |
| struct sk_buff_head list, *head = &sock->sk_receive_queue; |
| struct sk_buff *skb; |
| int i; |
| |
| __skb_queue_head_init(&list); |
| |
| /* |
| * Find the skb that holds this file in its SCM_RIGHTS. When found, |
| * remove this entry and rearrange the file array. |
| */ |
| skb = skb_dequeue(head); |
| while (skb) { |
| struct scm_fp_list *fp; |
| |
| fp = UNIXCB(skb).fp; |
| for (i = 0; i < fp->count; i++) { |
| int left; |
| |
| if (fp->fp[i] != file) |
| continue; |
| |
| unix_notinflight(fp->user, fp->fp[i]); |
| left = fp->count - 1 - i; |
| if (left) { |
| memmove(&fp->fp[i], &fp->fp[i + 1], |
| left * sizeof(struct file *)); |
| } |
| fp->count--; |
| if (!fp->count) { |
| kfree_skb(skb); |
| skb = NULL; |
| } else { |
| __skb_queue_tail(&list, skb); |
| } |
| fput(file); |
| file = NULL; |
| break; |
| } |
| |
| if (!file) |
| break; |
| |
| __skb_queue_tail(&list, skb); |
| |
| skb = skb_dequeue(head); |
| } |
| |
| if (skb_peek(&list)) { |
| spin_lock_irq(&head->lock); |
| while ((skb = __skb_dequeue(&list)) != NULL) |
| __skb_queue_tail(head, skb); |
| spin_unlock_irq(&head->lock); |
| } |
| #else |
| fput(io_file_from_index(ctx, index)); |
| #endif |
| } |
| |
| static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, |
| int index) |
| { |
| #if defined(CONFIG_UNIX) |
| struct sock *sock = ctx->ring_sock->sk; |
| struct sk_buff_head *head = &sock->sk_receive_queue; |
| struct sk_buff *skb; |
| |
| /* |
| * See if we can merge this file into an existing skb SCM_RIGHTS |
| * file set. If there's no room, fall back to allocating a new skb |
| * and filling it in. |
| */ |
| spin_lock_irq(&head->lock); |
| skb = skb_peek(head); |
| if (skb) { |
| struct scm_fp_list *fpl = UNIXCB(skb).fp; |
| |
| if (fpl->count < SCM_MAX_FD) { |
| __skb_unlink(skb, head); |
| spin_unlock_irq(&head->lock); |
| fpl->fp[fpl->count] = get_file(file); |
| unix_inflight(fpl->user, fpl->fp[fpl->count]); |
| fpl->count++; |
| spin_lock_irq(&head->lock); |
| __skb_queue_head(head, skb); |
| } else { |
| skb = NULL; |
| } |
| } |
| spin_unlock_irq(&head->lock); |
| |
| if (skb) { |
| fput(file); |
| return 0; |
| } |
| |
| return __io_sqe_files_scm(ctx, 1, index); |
| #else |
| return 0; |
| #endif |
| } |
| |
| static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg, |
| unsigned nr_args) |
| { |
| struct io_uring_files_update up; |
| __s32 __user *fds; |
| int fd, i, err; |
| __u32 done; |
| |
| if (!ctx->file_table) |
| return -ENXIO; |
| if (!nr_args) |
| return -EINVAL; |
| if (copy_from_user(&up, arg, sizeof(up))) |
| return -EFAULT; |
| if (check_add_overflow(up.offset, nr_args, &done)) |
| return -EOVERFLOW; |
| if (done > ctx->nr_user_files) |
| return -EINVAL; |
| |
| done = 0; |
| fds = (__s32 __user *) up.fds; |
| while (nr_args) { |
| struct fixed_file_table *table; |
| unsigned index; |
| |
| err = 0; |
| if (copy_from_user(&fd, &fds[done], sizeof(fd))) { |
| err = -EFAULT; |
| break; |
| } |
| i = array_index_nospec(up.offset, ctx->nr_user_files); |
| table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT]; |
| index = i & IORING_FILE_TABLE_MASK; |
| if (table->files[index]) { |
| io_sqe_file_unregister(ctx, i); |
| table->files[index] = NULL; |
| } |
| if (fd != -1) { |
| struct file *file; |
| |
| file = fget(fd); |
| if (!file) { |
| err = -EBADF; |
| break; |
| } |
| /* |
| * Don't allow io_uring instances to be registered. If |
| * UNIX isn't enabled, then this causes a reference |
| * cycle and this instance can never get freed. If UNIX |
| * is enabled we'll handle it just fine, but there's |
| * still no point in allowing a ring fd as it doesn't |
| * support regular read/write anyway. |
| */ |
| if (file->f_op == &io_uring_fops) { |
| fput(file); |
| err = -EBADF; |
| break; |
| } |
| table->files[index] = file; |
| err = io_sqe_file_register(ctx, file, i); |
| if (err) |
| break; |
| } |
| nr_args--; |
| done++; |
| up.offset++; |
| } |
| |
| return done ? done : err; |
| } |
| |
| static void io_put_work(struct io_wq_work *work) |
| { |
| struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
| |
| io_put_req(req); |
| } |
| |
| static void io_get_work(struct io_wq_work *work) |
| { |
| struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
| |
| refcount_inc(&req->refs); |
| } |
| |
| static int io_sq_offload_start(struct io_ring_ctx *ctx, |
| struct io_uring_params *p) |
| { |
| struct io_wq_data data; |
| unsigned concurrency; |
| int ret; |
| |
| init_waitqueue_head(&ctx->sqo_wait); |
| mmgrab(current->mm); |
| ctx->sqo_mm = current->mm; |
| |
| if (ctx->flags & IORING_SETUP_SQPOLL) { |
| ret = -EPERM; |
| if (!capable(CAP_SYS_ADMIN)) |
| goto err; |
| |
| ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle); |
| if (!ctx->sq_thread_idle) |
| ctx->sq_thread_idle = HZ; |
| |
| if (p->flags & IORING_SETUP_SQ_AFF) { |
| int cpu = p->sq_thread_cpu; |
| |
| ret = -EINVAL; |
| if (cpu >= nr_cpu_ids) |
| goto err; |
| if (!cpu_online(cpu)) |
| goto err; |
| |
| ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread, |
| ctx, cpu, |
| "io_uring-sq"); |
| } else { |
| ctx->sqo_thread = kthread_create(io_sq_thread, ctx, |
| "io_uring-sq"); |
| } |
| if (IS_ERR(ctx->sqo_thread)) { |
| ret = PTR_ERR(ctx->sqo_thread); |
| ctx->sqo_thread = NULL; |
| goto err; |
| } |
| wake_up_process(ctx->sqo_thread); |
| } else if (p->flags & IORING_SETUP_SQ_AFF) { |
| /* Can't have SQ_AFF without SQPOLL */ |
| ret = -EINVAL; |
| goto err; |
| } |
| |
| data.mm = ctx->sqo_mm; |
| data.user = ctx->user; |
| data.creds = ctx->creds; |
| data.get_work = io_get_work; |
| data.put_work = io_put_work; |
| |
| /* Do QD, or 4 * CPUS, whatever is smallest */ |
| concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); |
| ctx->io_wq = io_wq_create(concurrency, &data); |
| if (IS_ERR(ctx->io_wq)) { |
| ret = PTR_ERR(ctx->io_wq); |
| ctx->io_wq = NULL; |
| goto err; |
| } |
| |
| return 0; |
| err: |
| io_finish_async(ctx); |
| mmdrop(ctx->sqo_mm); |
| ctx->sqo_mm = NULL; |
| return ret; |
| } |
| |
| static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) |
| { |
| atomic_long_sub(nr_pages, &user->locked_vm); |
| } |
| |
| static int io_account_mem(struct user_struct *user, unsigned long nr_pages) |
| { |
| unsigned long page_limit, cur_pages, new_pages; |
| |
| /* Don't allow more pages than we can safely lock */ |
| page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; |
| |
| do { |
| cur_pages = atomic_long_read(&user->locked_vm); |
| new_pages = cur_pages + nr_pages; |
| if (new_pages > page_limit) |
| return -ENOMEM; |
| } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, |
| new_pages) != cur_pages); |
| |
| return 0; |
| } |
| |
| static void io_mem_free(void *ptr) |
| { |
| struct page *page; |
| |
| if (!ptr) |
| return; |
| |
| page = virt_to_head_page(ptr); |
| if (put_page_testzero(page)) |
| free_compound_page(page); |
| } |
| |
| static void *io_mem_alloc(size_t size) |
| { |
| gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP | |
| __GFP_NORETRY; |
| |
| return (void *) __get_free_pages(gfp_flags, get_order(size)); |
| } |
| |
| static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries, |
| size_t *sq_offset) |
| { |
| struct io_rings *rings; |
| size_t off, sq_array_size; |
| |
| off = struct_size(rings, cqes, cq_entries); |
| if (off == SIZE_MAX) |
| return SIZE_MAX; |
| |
| #ifdef CONFIG_SMP |
| off = ALIGN(off, SMP_CACHE_BYTES); |
| if (off == 0) |
| return SIZE_MAX; |
| #endif |
| |
| sq_array_size = array_size(sizeof(u32), sq_entries); |
| if (sq_array_size == SIZE_MAX) |
| return SIZE_MAX; |
| |
| if (check_add_overflow(off, sq_array_size, &off)) |
| return SIZE_MAX; |
| |
| if (sq_offset) |
| *sq_offset = off; |
| |
| return off; |
| } |
| |
| static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) |
| { |
| size_t pages; |
| |
| pages = (size_t)1 << get_order( |
| rings_size(sq_entries, cq_entries, NULL)); |
| pages += (size_t)1 << get_order( |
| array_size(sizeof(struct io_uring_sqe), sq_entries)); |
| |
| return pages; |
| } |
| |
| static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx) |
| { |
| int i, j; |
| |
| if (!ctx->user_bufs) |
| return -ENXIO; |
| |
| for (i = 0; i < ctx->nr_user_bufs; i++) { |
| struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; |
| |
| for (j = 0; j < imu->nr_bvecs; j++) |
| put_user_page(imu->bvec[j].bv_page); |
| |
| if (ctx->account_mem) |
| io_unaccount_mem(ctx->user, imu->nr_bvecs); |
| kvfree(imu->bvec); |
| imu->nr_bvecs = 0; |
| } |
| |
| kfree(ctx->user_bufs); |
| ctx->user_bufs = NULL; |
| ctx->nr_user_bufs = 0; |
| return 0; |
| } |
| |
| static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, |
| void __user *arg, unsigned index) |
| { |
| struct iovec __user *src; |
| |
| #ifdef CONFIG_COMPAT |
| if (ctx->compat) { |
| struct compat_iovec __user *ciovs; |
| struct compat_iovec ciov; |
| |
| ciovs = (struct compat_iovec __user *) arg; |
| if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) |
| return -EFAULT; |
| |
| dst->iov_base = (void __user *) (unsigned long) ciov.iov_base; |
| dst->iov_len = ciov.iov_len; |
| return 0; |
| } |
| #endif |
| src = (struct iovec __user *) arg; |
| if (copy_from_user(dst, &src[index], sizeof(*dst))) |
| return -EFAULT; |
| return 0; |
| } |
| |
| static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, |
| unsigned nr_args) |
| { |
| struct vm_area_struct **vmas = NULL; |
| struct page **pages = NULL; |
| int i, j, got_pages = 0; |
| int ret = -EINVAL; |
| |
| if (ctx->user_bufs) |
| return -EBUSY; |
| if (!nr_args || nr_args > UIO_MAXIOV) |
| return -EINVAL; |
| |
| ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf), |
| GFP_KERNEL); |
| if (!ctx->user_bufs) |
| return -ENOMEM; |
| |
| for (i = 0; i < nr_args; i++) { |
| struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; |
| unsigned long off, start, end, ubuf; |
| int pret, nr_pages; |
| struct iovec iov; |
| size_t size; |
| |
| ret = io_copy_iov(ctx, &iov, arg, i); |
| if (ret) |
| goto err; |
| |
| /* |
| * Don't impose further limits on the size and buffer |
| * constraints here, we'll -EINVAL later when IO is |
| * submitted if they are wrong. |
| */ |
| ret = -EFAULT; |
| if (!iov.iov_base || !iov.iov_len) |
| goto err; |
| |
| /* arbitrary limit, but we need something */ |
| if (iov.iov_len > SZ_1G) |
| goto err; |
| |
| ubuf = (unsigned long) iov.iov_base; |
| end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| start = ubuf >> PAGE_SHIFT; |
| nr_pages = end - start; |
| |
| if (ctx->account_mem) { |
| ret = io_account_mem(ctx->user, nr_pages); |
| if (ret) |
| goto err; |
| } |
| |
| ret = 0; |
| if (!pages || nr_pages > got_pages) { |
| kfree(vmas); |
| kfree(pages); |
| pages = kvmalloc_array(nr_pages, sizeof(struct page *), |
| GFP_KERNEL); |
| vmas = kvmalloc_array(nr_pages, |
| sizeof(struct vm_area_struct *), |
| GFP_KERNEL); |
| if (!pages || !vmas) { |
| ret = -ENOMEM; |
| if (ctx->account_mem) |
| io_unaccount_mem(ctx->user, nr_pages); |
| goto err; |
| } |
| got_pages = nr_pages; |
| } |
| |
| imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec), |
| GFP_KERNEL); |
| ret = -ENOMEM; |
| if (!imu->bvec) { |
| if (ctx->account_mem) |
| io_unaccount_mem(ctx->user, nr_pages); |
| goto err; |
| } |
| |
| ret = 0; |
| down_read(¤t->mm->mmap_sem); |
| pret = get_user_pages(ubuf, nr_pages, |
| FOLL_WRITE | FOLL_LONGTERM, |
| pages, vmas); |
| if (pret == nr_pages) { |
| /* don't support file backed memory */ |
| for (j = 0; j < nr_pages; j++) { |
| struct vm_area_struct *vma = vmas[j]; |
| |
| if (vma->vm_file && |
| !is_file_hugepages(vma->vm_file)) { |
| ret = -EOPNOTSUPP; |
| break; |
| } |
| } |
| } else { |
| ret = pret < 0 ? pret : -EFAULT; |
| } |
| up_read(¤t->mm->mmap_sem); |
| if (ret) { |
| /* |
| * if we did partial map, or found file backed vmas, |
| * release any pages we did get |
| */ |
| if (pret > 0) |
| put_user_pages(pages, pret); |
| if (ctx->account_mem) |
| io_unaccount_mem(ctx->user, nr_pages); |
| kvfree(imu->bvec); |
| goto err; |
| } |
| |
| off = ubuf & ~PAGE_MASK; |
| size = iov.iov_len; |
| for (j = 0; j < nr_pages; j++) { |
| size_t vec_len; |
| |
| vec_len = min_t(size_t, size, PAGE_SIZE - off); |
| imu->bvec[j].bv_page = pages[j]; |
| imu->bvec[j].bv_len = vec_len; |
| imu->bvec[j].bv_offset = off; |
| off = 0; |
| size -= vec_len; |
| } |
| /* store original address for later verification */ |
| imu->ubuf = ubuf; |
| imu->len = iov.iov_len; |
| imu->nr_bvecs = nr_pages; |
| |
| ctx->nr_user_bufs++; |
| } |
| kvfree(pages); |
| kvfree(vmas); |
| return 0; |
| err: |
| kvfree(pages); |
| kvfree(vmas); |
| io_sqe_buffer_unregister(ctx); |
| return ret; |
| } |
| |
| static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg) |
| { |
| __s32 __user *fds = arg; |
| int fd; |
| |
| if (ctx->cq_ev_fd) |
| return -EBUSY; |
| |
| if (copy_from_user(&fd, fds, sizeof(*fds))) |
| return -EFAULT; |
| |
| ctx->cq_ev_fd = eventfd_ctx_fdget(fd); |
| if (IS_ERR(ctx->cq_ev_fd)) { |
| int ret = PTR_ERR(ctx->cq_ev_fd); |
| ctx->cq_ev_fd = NULL; |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| static int io_eventfd_unregister(struct io_ring_ctx *ctx) |
| { |
| if (ctx->cq_ev_fd) { |
| eventfd_ctx_put(ctx->cq_ev_fd); |
| ctx->cq_ev_fd = NULL; |
| return 0; |
| } |
| |
| return -ENXIO; |
| } |
| |
| static void io_ring_ctx_free(struct io_ring_ctx *ctx) |
| { |
| io_finish_async(ctx); |
| if (ctx->sqo_mm) |
| mmdrop(ctx->sqo_mm); |
| |
| io_iopoll_reap_events(ctx); |
| io_sqe_buffer_unregister(ctx); |
| io_sqe_files_unregister(ctx); |
| io_eventfd_unregister(ctx); |
| |
| #if defined(CONFIG_UNIX) |
| if (ctx->ring_sock) { |
| ctx->ring_sock->file = NULL; /* so that iput() is called */ |
| sock_release(ctx->ring_sock); |
| } |
| #endif |
| |
| io_mem_free(ctx->rings); |
| io_mem_free(ctx->sq_sqes); |
| |
| percpu_ref_exit(&ctx->refs); |
| if (ctx->account_mem) |
| io_unaccount_mem(ctx->user, |
| ring_pages(ctx->sq_entries, ctx->cq_entries)); |
| free_uid(ctx->user); |
| put_cred(ctx->creds); |
| kfree(ctx->completions); |
| kfree(ctx->cancel_hash); |
| kmem_cache_free(req_cachep, ctx->fallback_req); |
| kfree(ctx); |
| } |
| |
| static __poll_t io_uring_poll(struct file *file, poll_table *wait) |
| { |
| struct io_ring_ctx *ctx = file->private_data; |
| __poll_t mask = 0; |
| |
| poll_wait(file, &ctx->cq_wait, wait); |
| /* |
| * synchronizes with barrier from wq_has_sleeper call in |
| * io_commit_cqring |
| */ |
| smp_rmb(); |
| if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head != |
| ctx->rings->sq_ring_entries) |
| mask |= EPOLLOUT | EPOLLWRNORM; |
| if (READ_ONCE(ctx->rings->cq.head) != ctx->cached_cq_tail) |
| mask |= EPOLLIN | EPOLLRDNORM; |
| |
| return mask; |
| } |
| |
| static int io_uring_fasync(int fd, struct file *file, int on) |
| { |
| struct io_ring_ctx *ctx = file->private_data; |
| |
| return fasync_helper(fd, file, on, &ctx->cq_fasync); |
| } |
| |
| static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) |
| { |
| mutex_lock(&ctx->uring_lock); |
| percpu_ref_kill(&ctx->refs); |
| mutex_unlock(&ctx->uring_lock); |
| |
| io_kill_timeouts(ctx); |
| io_poll_remove_all(ctx); |
| |
| if (ctx->io_wq) |
| io_wq_cancel_all(ctx->io_wq); |
| |
| io_iopoll_reap_events(ctx); |
| /* if we failed setting up the ctx, we might not have any rings */ |
| if (ctx->rings) |
| io_cqring_overflow_flush(ctx, true); |
| wait_for_completion(&ctx->completions[0]); |
| io_ring_ctx_free(ctx); |
| } |
| |
| static int io_uring_release(struct inode *inode, struct file *file) |
| { |
| struct io_ring_ctx *ctx = file->private_data; |
| |
| file->private_data = NULL; |
| io_ring_ctx_wait_and_kill(ctx); |
| return 0; |
| } |
| |
| static void io_uring_cancel_files(struct io_ring_ctx *ctx, |
| struct files_struct *files) |
| { |
| struct io_kiocb *req; |
| DEFINE_WAIT(wait); |
| |
| while (!list_empty_careful(&ctx->inflight_list)) { |
| struct io_kiocb *cancel_req = NULL; |
| |
| spin_lock_irq(&ctx->inflight_lock); |
| list_for_each_entry(req, &ctx->inflight_list, inflight_entry) { |
| if (req->work.files != files) |
| continue; |
| /* req is being completed, ignore */ |
| if (!refcount_inc_not_zero(&req->refs)) |
| continue; |
| cancel_req = req; |
| break; |
| } |
| if (cancel_req) |
| prepare_to_wait(&ctx->inflight_wait, &wait, |
| TASK_UNINTERRUPTIBLE); |
| spin_unlock_irq(&ctx->inflight_lock); |
| |
| /* We need to keep going until we don't find a matching req */ |
| if (!cancel_req) |
| break; |
| |
| io_wq_cancel_work(ctx->io_wq, &cancel_req->work); |
| io_put_req(cancel_req); |
| schedule(); |
| } |
| finish_wait(&ctx->inflight_wait, &wait); |
| } |
| |
| static int io_uring_flush(struct file *file, void *data) |
| { |
| struct io_ring_ctx *ctx = file->private_data; |
| |
| io_uring_cancel_files(ctx, data); |
| if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) { |
| io_cqring_overflow_flush(ctx, true); |
| io_wq_cancel_all(ctx->io_wq); |
| } |
| return 0; |
| } |
| |
| static void *io_uring_validate_mmap_request(struct file *file, |
| loff_t pgoff, size_t sz) |
| { |
| struct io_ring_ctx *ctx = file->private_data; |
| loff_t offset = pgoff << PAGE_SHIFT; |
| struct page *page; |
| void *ptr; |
| |
| switch (offset) { |
| case IORING_OFF_SQ_RING: |
| case IORING_OFF_CQ_RING: |
| ptr = ctx->rings; |
| break; |
| case IORING_OFF_SQES: |
| ptr = ctx->sq_sqes; |
| break; |
| default: |
| return ERR_PTR(-EINVAL); |
| } |
| |
| page = virt_to_head_page(ptr); |
| if (sz > page_size(page)) |
| return ERR_PTR(-EINVAL); |
| |
| return ptr; |
| } |
| |
| #ifdef CONFIG_MMU |
| |
| static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| size_t sz = vma->vm_end - vma->vm_start; |
| unsigned long pfn; |
| void *ptr; |
| |
| ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz); |
| if (IS_ERR(ptr)) |
| return PTR_ERR(ptr); |
| |
| pfn = virt_to_phys(ptr) >> PAGE_SHIFT; |
| return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); |
| } |
| |
| #else /* !CONFIG_MMU */ |
| |
| static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL; |
| } |
| |
| static unsigned int io_uring_nommu_mmap_capabilities(struct file *file) |
| { |
| return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; |
| } |
| |
| static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, |
| unsigned long addr, unsigned long len, |
| unsigned long pgoff, unsigned long flags) |
| { |
| void *ptr; |
| |
| ptr = io_uring_validate_mmap_request(file, pgoff, len); |
| if (IS_ERR(ptr)) |
| return PTR_ERR(ptr); |
| |
| return (unsigned long) ptr; |
| } |
| |
| #endif /* !CONFIG_MMU */ |
| |
| SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, |
| u32, min_complete, u32, flags, const sigset_t __user *, sig, |
| size_t, sigsz) |
| { |
| struct io_ring_ctx *ctx; |
| long ret = -EBADF; |
| int submitted = 0; |
| struct fd f; |
| |
| if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP)) |
| return -EINVAL; |
| |
| f = fdget(fd); |
| if (!f.file) |
| return -EBADF; |
| |
| ret = -EOPNOTSUPP; |
| if (f.file->f_op != &io_uring_fops) |
| goto out_fput; |
| |
| ret = -ENXIO; |
| ctx = f.file->private_data; |
| if (!percpu_ref_tryget(&ctx->refs)) |
| goto out_fput; |
| |
| /* |
| * For SQ polling, the thread will do all submissions and completions. |
| * Just return the requested submit count, and wake the thread if |
| * we were asked to. |
| */ |
| ret = 0; |
| if (ctx->flags & IORING_SETUP_SQPOLL) { |
| if (!list_empty_careful(&ctx->cq_overflow_list)) |
| io_cqring_overflow_flush(ctx, false); |
| if (flags & IORING_ENTER_SQ_WAKEUP) |
| wake_up(&ctx->sqo_wait); |
| submitted = to_submit; |
| } else if (to_submit) { |
| struct mm_struct *cur_mm; |
| |
| to_submit = min(to_submit, ctx->sq_entries); |
| mutex_lock(&ctx->uring_lock); |
| /* already have mm, so io_submit_sqes() won't try to grab it */ |
| cur_mm = ctx->sqo_mm; |
| submitted = io_submit_sqes(ctx, to_submit, f.file, fd, |
| &cur_mm, false); |
| mutex_unlock(&ctx->uring_lock); |
| } |
| if (flags & IORING_ENTER_GETEVENTS) { |
| unsigned nr_events = 0; |
| |
| min_complete = min(min_complete, ctx->cq_entries); |
| |
| if (ctx->flags & IORING_SETUP_IOPOLL) { |
| ret = io_iopoll_check(ctx, &nr_events, min_complete); |
| } else { |
| ret = io_cqring_wait(ctx, min_complete, sig, sigsz); |
| } |
| } |
| |
| percpu_ref_put(&ctx->refs); |
| out_fput: |
| fdput(f); |
| return submitted ? submitted : ret; |
| } |
| |
| static const struct file_operations io_uring_fops = { |
| .release = io_uring_release, |
| .flush = io_uring_flush, |
| .mmap = io_uring_mmap, |
| #ifndef CONFIG_MMU |
| .get_unmapped_area = io_uring_nommu_get_unmapped_area, |
| .mmap_capabilities = io_uring_nommu_mmap_capabilities, |
| #endif |
| .poll = io_uring_poll, |
| .fasync = io_uring_fasync, |
| }; |
| |
| static int io_allocate_scq_urings(struct io_ring_ctx *ctx, |
| struct io_uring_params *p) |
| { |
| struct io_rings *rings; |
| size_t size, sq_array_offset; |
| |
| size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset); |
| if (size == SIZE_MAX) |
| return -EOVERFLOW; |
| |
| rings = io_mem_alloc(size); |
| if (!rings) |
| return -ENOMEM; |
| |
| ctx->rings = rings; |
| ctx->sq_array = (u32 *)((char *)rings + sq_array_offset); |
| rings->sq_ring_mask = p->sq_entries - 1; |
| rings->cq_ring_mask = p->cq_entries - 1; |
| rings->sq_ring_entries = p->sq_entries; |
| rings->cq_ring_entries = p->cq_entries; |
| ctx->sq_mask = rings->sq_ring_mask; |
| ctx->cq_mask = rings->cq_ring_mask; |
| ctx->sq_entries = rings->sq_ring_entries; |
| ctx->cq_entries = rings->cq_ring_entries; |
| |
| size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); |
| if (size == SIZE_MAX) { |
| io_mem_free(ctx->rings); |
| ctx->rings = NULL; |
| return -EOVERFLOW; |
| } |
| |
| ctx->sq_sqes = io_mem_alloc(size); |
| if (!ctx->sq_sqes) { |
| io_mem_free(ctx->rings); |
| ctx->rings = NULL; |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Allocate an anonymous fd, this is what constitutes the application |
| * visible backing of an io_uring instance. The application mmaps this |
| * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled, |
| * we have to tie this fd to a socket for file garbage collection purposes. |
| */ |
| static int io_uring_get_fd(struct io_ring_ctx *ctx) |
| { |
| struct file *file; |
| int ret; |
| |
| #if defined(CONFIG_UNIX) |
| ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, |
| &ctx->ring_sock); |
| if (ret) |
| return ret; |
| #endif |
| |
| ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC); |
| if (ret < 0) |
| goto err; |
| |
| file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, |
| O_RDWR | O_CLOEXEC); |
| if (IS_ERR(file)) { |
| put_unused_fd(ret); |
| ret = PTR_ERR(file); |
| goto err; |
| } |
| |
| #if defined(CONFIG_UNIX) |
| ctx->ring_sock->file = file; |
| ctx->ring_sock->sk->sk_user_data = ctx; |
| #endif |
| fd_install(ret, file); |
| return ret; |
| err: |
| #if defined(CONFIG_UNIX) |
| sock_release(ctx->ring_sock); |
| ctx->ring_sock = NULL; |
| #endif |
| return ret; |
| } |
| |
| static int io_uring_create(unsigned entries, struct io_uring_params *p) |
| { |
| struct user_struct *user = NULL; |
| struct io_ring_ctx *ctx; |
| bool account_mem; |
| int ret; |
| |
| if (!entries || entries > IORING_MAX_ENTRIES) |
| return -EINVAL; |
| |
| /* |
| * Use twice as many entries for the CQ ring. It's possible for the |
| * application to drive a higher depth than the size of the SQ ring, |
| * since the sqes are only used at submission time. This allows for |
| * some flexibility in overcommitting a bit. If the application has |
| * set IORING_SETUP_CQSIZE, it will have passed in the desired number |
| * of CQ ring entries manually. |
| */ |
| p->sq_entries = roundup_pow_of_two(entries); |
| if (p->flags & IORING_SETUP_CQSIZE) { |
| /* |
| * If IORING_SETUP_CQSIZE is set, we do the same roundup |
| * to a power-of-two, if it isn't already. We do NOT impose |
| * any cq vs sq ring sizing. |
| */ |
| if (p->cq_entries < p->sq_entries || p->cq_entries > IORING_MAX_CQ_ENTRIES) |
| return -EINVAL; |
| p->cq_entries = roundup_pow_of_two(p->cq_entries); |
| } else { |
| p->cq_entries = 2 * p->sq_entries; |
| } |
| |
| user = get_uid(current_user()); |
| account_mem = !capable(CAP_IPC_LOCK); |
| |
| if (account_mem) { |
| ret = io_account_mem(user, |
| ring_pages(p->sq_entries, p->cq_entries)); |
| if (ret) { |
| free_uid(user); |
| return ret; |
| } |
| } |
| |
| ctx = io_ring_ctx_alloc(p); |
| if (!ctx) { |
| if (account_mem) |
| io_unaccount_mem(user, ring_pages(p->sq_entries, |
| p->cq_entries)); |
| free_uid(user); |
| return -ENOMEM; |
| } |
| ctx->compat = in_compat_syscall(); |
| ctx->account_mem = account_mem; |
| ctx->user = user; |
| ctx->creds = get_current_cred(); |
| |
| ret = io_allocate_scq_urings(ctx, p); |
| if (ret) |
| goto err; |
| |
| ret = io_sq_offload_start(ctx, p); |
| if (ret) |
| goto err; |
| |
| memset(&p->sq_off, 0, sizeof(p->sq_off)); |
| p->sq_off.head = offsetof(struct io_rings, sq.head); |
| p->sq_off.tail = offsetof(struct io_rings, sq.tail); |
| p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask); |
| p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries); |
| p->sq_off.flags = offsetof(struct io_rings, sq_flags); |
| p->sq_off.dropped = offsetof(struct io_rings, sq_dropped); |
| p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings; |
| |
| memset(&p->cq_off, 0, sizeof(p->cq_off)); |
| p->cq_off.head = offsetof(struct io_rings, cq.head); |
| p->cq_off.tail = offsetof(struct io_rings, cq.tail); |
| p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask); |
| p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries); |
| p->cq_off.overflow = offsetof(struct io_rings, cq_overflow); |
| p->cq_off.cqes = offsetof(struct io_rings, cqes); |
| |
| /* |
| * Install ring fd as the very last thing, so we don't risk someone |
| * having closed it before we finish setup |
| */ |
| ret = io_uring_get_fd(ctx); |
| if (ret < 0) |
| goto err; |
| |
| p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | |
| IORING_FEAT_SUBMIT_STABLE; |
| trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); |
| return ret; |
| err: |
| io_ring_ctx_wait_and_kill(ctx); |
| return ret; |
| } |
| |
| /* |
| * Sets up an aio uring context, and returns the fd. Applications asks for a |
| * ring size, we return the actual sq/cq ring sizes (among other things) in the |
| * params structure passed in. |
| */ |
| static long io_uring_setup(u32 entries, struct io_uring_params __user *params) |
| { |
| struct io_uring_params p; |
| long ret; |
| int i; |
| |
| if (copy_from_user(&p, params, sizeof(p))) |
| return -EFAULT; |
| for (i = 0; i < ARRAY_SIZE(p.resv); i++) { |
| if (p.resv[i]) |
| return -EINVAL; |
| } |
| |
| if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | |
| IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE)) |
| return -EINVAL; |
| |
| ret = io_uring_create(entries, &p); |
| if (ret < 0) |
| return ret; |
| |
| if (copy_to_user(params, &p, sizeof(p))) |
| return -EFAULT; |
| |
| return ret; |
| } |
| |
| SYSCALL_DEFINE2(io_uring_setup, u32, entries, |
| struct io_uring_params __user *, params) |
| { |
| return io_uring_setup(entries, params); |
| } |
| |
| static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, |
| void __user *arg, unsigned nr_args) |
| __releases(ctx->uring_lock) |
| __acquires(ctx->uring_lock) |
| { |
| int ret; |
| |
| /* |
| * We're inside the ring mutex, if the ref is already dying, then |
| * someone else killed the ctx or is already going through |
| * io_uring_register(). |
| */ |
| if (percpu_ref_is_dying(&ctx->refs)) |
| return -ENXIO; |
| |
| percpu_ref_kill(&ctx->refs); |
| |
| /* |
| * Drop uring mutex before waiting for references to exit. If another |
| * thread is currently inside io_uring_enter() it might need to grab |
| * the uring_lock to make progress. If we hold it here across the drain |
| * wait, then we can deadlock. It's safe to drop the mutex here, since |
| * no new references will come in after we've killed the percpu ref. |
| */ |
| mutex_unlock(&ctx->uring_lock); |
| wait_for_completion(&ctx->completions[0]); |
| mutex_lock(&ctx->uring_lock); |
| |
| switch (opcode) { |
| case IORING_REGISTER_BUFFERS: |
| ret = io_sqe_buffer_register(ctx, arg, nr_args); |
| break; |
| case IORING_UNREGISTER_BUFFERS: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_sqe_buffer_unregister(ctx); |
| break; |
| case IORING_REGISTER_FILES: |
| ret = io_sqe_files_register(ctx, arg, nr_args); |
| break; |
| case IORING_UNREGISTER_FILES: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_sqe_files_unregister(ctx); |
| break; |
| case IORING_REGISTER_FILES_UPDATE: |
| ret = io_sqe_files_update(ctx, arg, nr_args); |
| break; |
| case IORING_REGISTER_EVENTFD: |
| ret = -EINVAL; |
| if (nr_args != 1) |
| break; |
| ret = io_eventfd_register(ctx, arg); |
| break; |
| case IORING_UNREGISTER_EVENTFD: |
| ret = -EINVAL; |
| if (arg || nr_args) |
| break; |
| ret = io_eventfd_unregister(ctx); |
| break; |
| default: |
| ret = -EINVAL; |
| break; |
| } |
| |
| /* bring the ctx back to life */ |
| reinit_completion(&ctx->completions[0]); |
| percpu_ref_reinit(&ctx->refs); |
| return ret; |
| } |
| |
| SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, |
| void __user *, arg, unsigned int, nr_args) |
| { |
| struct io_ring_ctx *ctx; |
| long ret = -EBADF; |
| struct fd f; |
| |
| f = fdget(fd); |
| if (!f.file) |
| return -EBADF; |
| |
| ret = -EOPNOTSUPP; |
| if (f.file->f_op != &io_uring_fops) |
| goto out_fput; |
| |
| ctx = f.file->private_data; |
| |
| mutex_lock(&ctx->uring_lock); |
| ret = __io_uring_register(ctx, opcode, arg, nr_args); |
| mutex_unlock(&ctx->uring_lock); |
| trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, |
| ctx->cq_ev_fd != NULL, ret); |
| out_fput: |
| fdput(f); |
| return ret; |
| } |
| |
| static int __init io_uring_init(void) |
| { |
| req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); |
| return 0; |
| }; |
| __initcall(io_uring_init); |