| // 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/workqueue.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 <uapi/linux/io_uring.h> |
| |
| #include "internal.h" |
| |
| #define IORING_MAX_ENTRIES 32768 |
| #define IORING_MAX_FIXED_FILES 1024 |
| |
| 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 thatn 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 async_list { |
| spinlock_t lock; |
| atomic_t cnt; |
| struct list_head list; |
| |
| struct file *file; |
| off_t io_start; |
| size_t io_len; |
| }; |
| |
| struct io_ring_ctx { |
| struct { |
| struct percpu_ref refs; |
| } ____cacheline_aligned_in_smp; |
| |
| struct { |
| unsigned int flags; |
| bool compat; |
| bool account_mem; |
| |
| /* |
| * 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; |
| struct io_uring_sqe *sq_sqes; |
| |
| struct list_head defer_list; |
| struct list_head timeout_list; |
| } ____cacheline_aligned_in_smp; |
| |
| /* IO offload */ |
| struct workqueue_struct *sqo_wq[2]; |
| struct task_struct *sqo_thread; /* if using sq thread polling */ |
| struct mm_struct *sqo_mm; |
| wait_queue_head_t sqo_wait; |
| struct completion sqo_thread_started; |
| |
| struct { |
| unsigned cached_cq_tail; |
| atomic_t cached_cq_overflow; |
| unsigned cq_entries; |
| unsigned cq_mask; |
| struct wait_queue_head cq_wait; |
| struct fasync_struct *cq_fasync; |
| struct eventfd_ctx *cq_ev_fd; |
| atomic_t cq_timeouts; |
| } ____cacheline_aligned_in_smp; |
| |
| struct io_rings *rings; |
| |
| /* |
| * 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 file **user_files; |
| unsigned nr_user_files; |
| |
| /* if used, fixed mapped user buffers */ |
| unsigned nr_user_bufs; |
| struct io_mapped_ubuf *user_bufs; |
| |
| struct user_struct *user; |
| |
| struct completion ctx_done; |
| |
| 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 list_head cancel_list; |
| } ____cacheline_aligned_in_smp; |
| |
| struct async_list pending_async[2]; |
| |
| #if defined(CONFIG_UNIX) |
| struct socket *ring_sock; |
| #endif |
| }; |
| |
| struct sqe_submit { |
| const struct io_uring_sqe *sqe; |
| unsigned short index; |
| u32 sequence; |
| bool has_user; |
| bool needs_lock; |
| bool needs_fixed_file; |
| }; |
| |
| /* |
| * 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 { |
| struct file *file; |
| struct hrtimer timer; |
| }; |
| |
| /* |
| * 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; |
| struct io_timeout timeout; |
| }; |
| |
| struct sqe_submit submit; |
| |
| struct io_ring_ctx *ctx; |
| struct list_head list; |
| 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_SEQ_PREV 8 /* sequential with previous */ |
| #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_DONE 128 /* linked sqes done */ |
| #define REQ_F_FAIL_LINK 256 /* fail rest of links */ |
| #define REQ_F_SHADOW_DRAIN 512 /* link-drain shadow req */ |
| #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 */ |
| u64 user_data; |
| u32 result; |
| u32 sequence; |
| |
| struct work_struct 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_sq_wq_submit_work(struct work_struct *work); |
| static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data, |
| long res); |
| static void __io_free_req(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->ctx_done); |
| } |
| |
| static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) |
| { |
| struct io_ring_ctx *ctx; |
| int i; |
| |
| ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); |
| if (!ctx) |
| return NULL; |
| |
| if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, |
| PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) { |
| kfree(ctx); |
| return NULL; |
| } |
| |
| ctx->flags = p->flags; |
| init_waitqueue_head(&ctx->cq_wait); |
| init_completion(&ctx->ctx_done); |
| init_completion(&ctx->sqo_thread_started); |
| mutex_init(&ctx->uring_lock); |
| init_waitqueue_head(&ctx->wait); |
| for (i = 0; i < ARRAY_SIZE(ctx->pending_async); i++) { |
| spin_lock_init(&ctx->pending_async[i].lock); |
| INIT_LIST_HEAD(&ctx->pending_async[i].list); |
| atomic_set(&ctx->pending_async[i].cnt, 0); |
| } |
| spin_lock_init(&ctx->completion_lock); |
| INIT_LIST_HEAD(&ctx->poll_list); |
| INIT_LIST_HEAD(&ctx->cancel_list); |
| INIT_LIST_HEAD(&ctx->defer_list); |
| INIT_LIST_HEAD(&ctx->timeout_list); |
| return ctx; |
| } |
| |
| static inline bool __io_sequence_defer(struct io_ring_ctx *ctx, |
| struct io_kiocb *req) |
| { |
| return req->sequence != ctx->cached_cq_tail + ctx->cached_sq_dropped |
| + atomic_read(&ctx->cached_cq_overflow); |
| } |
| |
| static inline bool io_sequence_defer(struct io_ring_ctx *ctx, |
| struct io_kiocb *req) |
| { |
| if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) != REQ_F_IO_DRAIN) |
| return false; |
| |
| return __io_sequence_defer(ctx, req); |
| } |
| |
| 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 && !io_sequence_defer(ctx, 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 && !__io_sequence_defer(ctx, 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 void io_queue_async_work(struct io_ring_ctx *ctx, |
| struct io_kiocb *req) |
| { |
| int rw = 0; |
| |
| if (req->submit.sqe) { |
| switch (req->submit.sqe->opcode) { |
| case IORING_OP_WRITEV: |
| case IORING_OP_WRITE_FIXED: |
| rw = !(req->rw.ki_flags & IOCB_DIRECT); |
| break; |
| } |
| } |
| |
| queue_work(ctx->sqo_wq[rw], &req->work); |
| } |
| |
| static void io_kill_timeout(struct io_kiocb *req) |
| { |
| int ret; |
| |
| ret = hrtimer_try_to_cancel(&req->timeout.timer); |
| if (ret != -1) { |
| atomic_inc(&req->ctx->cq_timeouts); |
| list_del(&req->list); |
| io_cqring_fill_event(req->ctx, req->user_data, 0); |
| __io_free_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) { |
| if (req->flags & REQ_F_SHADOW_DRAIN) { |
| /* Just for drain, free it. */ |
| __io_free_req(req); |
| continue; |
| } |
| req->flags |= REQ_F_IO_DRAINED; |
| io_queue_async_work(ctx, 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_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data, |
| long res) |
| { |
| struct io_uring_cqe *cqe; |
| |
| /* |
| * 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 (cqe) { |
| WRITE_ONCE(cqe->user_data, ki_user_data); |
| WRITE_ONCE(cqe->res, res); |
| WRITE_ONCE(cqe->flags, 0); |
| } else { |
| WRITE_ONCE(ctx->rings->cq_overflow, |
| atomic_inc_return(&ctx->cached_cq_overflow)); |
| } |
| } |
| |
| 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); |
| } |
| |
| static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 user_data, |
| long res) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| io_cqring_fill_event(ctx, user_data, res); |
| io_commit_cqring(ctx); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| |
| io_cqring_ev_posted(ctx); |
| } |
| |
| 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 out; |
| } 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 out; |
| 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++; |
| } |
| |
| 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; |
| return req; |
| out: |
| 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) |
| { |
| if (req->file && !(req->flags & REQ_F_FIXED_FILE)) |
| fput(req->file); |
| percpu_ref_put(&req->ctx->refs); |
| kmem_cache_free(req_cachep, req); |
| } |
| |
| static void io_req_link_next(struct io_kiocb *req) |
| { |
| struct io_kiocb *nxt; |
| |
| /* |
| * 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. |
| */ |
| nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, list); |
| if (nxt) { |
| list_del(&nxt->list); |
| if (!list_empty(&req->link_list)) { |
| INIT_LIST_HEAD(&nxt->link_list); |
| list_splice(&req->link_list, &nxt->link_list); |
| nxt->flags |= REQ_F_LINK; |
| } |
| |
| nxt->flags |= REQ_F_LINK_DONE; |
| INIT_WORK(&nxt->work, io_sq_wq_submit_work); |
| io_queue_async_work(req->ctx, nxt); |
| } |
| } |
| |
| /* |
| * Called if REQ_F_LINK is set, and we fail the head request |
| */ |
| static void io_fail_links(struct io_kiocb *req) |
| { |
| struct io_kiocb *link; |
| |
| while (!list_empty(&req->link_list)) { |
| link = list_first_entry(&req->link_list, struct io_kiocb, list); |
| list_del(&link->list); |
| |
| io_cqring_add_event(req->ctx, link->user_data, -ECANCELED); |
| __io_free_req(link); |
| } |
| } |
| |
| static void io_free_req(struct io_kiocb *req) |
| { |
| /* |
| * 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_LINK) { |
| if (req->flags & REQ_F_FAIL_LINK) |
| io_fail_links(req); |
| else |
| io_req_link_next(req); |
| } |
| |
| __io_free_req(req); |
| } |
| |
| static void io_put_req(struct io_kiocb *req) |
| { |
| if (refcount_dec_and_test(&req->refs)) |
| io_free_req(req); |
| } |
| |
| static unsigned io_cqring_events(struct io_rings *rings) |
| { |
| /* 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(ctx, req->user_data, 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) { |
| 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 mininum 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->rings)) |
| 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 void io_complete_rw(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 ((req->flags & REQ_F_LINK) && res != req->result) |
| req->flags |= REQ_F_FAIL_LINK; |
| io_cqring_add_event(req->ctx, req->user_data, res); |
| io_put_req(req); |
| } |
| |
| 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 ((req->flags & REQ_F_LINK) && res != req->result) |
| req->flags |= REQ_F_FAIL_LINK; |
| 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)) |
| 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, const struct sqe_submit *s, |
| bool force_nonblock) |
| { |
| const struct io_uring_sqe *sqe = s->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; |
| |
| /* |
| * 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; |
| return -EAGAIN; |
| } |
| |
| 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; |
| } 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 int 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 0; |
| } |
| |
| static ssize_t io_import_iovec(struct io_ring_ctx *ctx, int rw, |
| const struct sqe_submit *s, struct iovec **iovec, |
| struct iov_iter *iter) |
| { |
| const struct io_uring_sqe *sqe = s->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) { |
| ssize_t ret = io_import_fixed(ctx, rw, sqe, iter); |
| *iovec = NULL; |
| return ret; |
| } |
| |
| if (!s->has_user) |
| return -EFAULT; |
| |
| #ifdef CONFIG_COMPAT |
| if (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); |
| } |
| |
| static inline bool io_should_merge(struct async_list *al, struct kiocb *kiocb) |
| { |
| if (al->file == kiocb->ki_filp) { |
| off_t start, end; |
| |
| /* |
| * Allow merging if we're anywhere in the range of the same |
| * page. Generally this happens for sub-page reads or writes, |
| * and it's beneficial to allow the first worker to bring the |
| * page in and the piggy backed work can then work on the |
| * cached page. |
| */ |
| start = al->io_start & PAGE_MASK; |
| end = (al->io_start + al->io_len + PAGE_SIZE - 1) & PAGE_MASK; |
| if (kiocb->ki_pos >= start && kiocb->ki_pos <= end) |
| return true; |
| } |
| |
| al->file = NULL; |
| return false; |
| } |
| |
| /* |
| * Make a note of the last file/offset/direction we punted to async |
| * context. We'll use this information to see if we can piggy back a |
| * sequential request onto the previous one, if it's still hasn't been |
| * completed by the async worker. |
| */ |
| static void io_async_list_note(int rw, struct io_kiocb *req, size_t len) |
| { |
| struct async_list *async_list = &req->ctx->pending_async[rw]; |
| struct kiocb *kiocb = &req->rw; |
| struct file *filp = kiocb->ki_filp; |
| |
| if (io_should_merge(async_list, kiocb)) { |
| unsigned long max_bytes; |
| |
| /* Use 8x RA size as a decent limiter for both reads/writes */ |
| max_bytes = filp->f_ra.ra_pages << (PAGE_SHIFT + 3); |
| if (!max_bytes) |
| max_bytes = VM_READAHEAD_PAGES << (PAGE_SHIFT + 3); |
| |
| /* If max len are exceeded, reset the state */ |
| if (async_list->io_len + len <= max_bytes) { |
| req->flags |= REQ_F_SEQ_PREV; |
| async_list->io_len += len; |
| } else { |
| async_list->file = NULL; |
| } |
| } |
| |
| /* New file? Reset state. */ |
| if (async_list->file != filp) { |
| async_list->io_start = kiocb->ki_pos; |
| async_list->io_len = len; |
| async_list->file = filp; |
| } |
| } |
| |
| /* |
| * 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 = iov_iter_iovec(iter); |
| ssize_t nr; |
| |
| 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 (nr < 0) { |
| if (!ret) |
| ret = nr; |
| break; |
| } |
| ret += nr; |
| if (nr != iovec.iov_len) |
| break; |
| iov_iter_advance(iter, nr); |
| } |
| |
| return ret; |
| } |
| |
| static int io_read(struct io_kiocb *req, const struct sqe_submit *s, |
| 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 read_size, ret; |
| |
| ret = io_prep_rw(req, s, force_nonblock); |
| if (ret) |
| return ret; |
| file = kiocb->ki_filp; |
| |
| if (unlikely(!(file->f_mode & FMODE_READ))) |
| return -EBADF; |
| |
| ret = io_import_iovec(req->ctx, READ, s, &iovec, &iter); |
| if (ret < 0) |
| return ret; |
| |
| read_size = ret; |
| if (req->flags & REQ_F_LINK) |
| req->result = read_size; |
| |
| 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 < read_size) |
| ret2 = -EAGAIN; |
| /* Catch -EAGAIN return for forced non-blocking submission */ |
| if (!force_nonblock || ret2 != -EAGAIN) { |
| io_rw_done(kiocb, ret2); |
| } else { |
| /* |
| * If ->needs_lock is true, we're already in async |
| * context. |
| */ |
| if (!s->needs_lock) |
| io_async_list_note(READ, req, iov_count); |
| ret = -EAGAIN; |
| } |
| } |
| kfree(iovec); |
| return ret; |
| } |
| |
| static int io_write(struct io_kiocb *req, const struct sqe_submit *s, |
| 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; |
| |
| ret = io_prep_rw(req, s, force_nonblock); |
| if (ret) |
| return ret; |
| |
| file = kiocb->ki_filp; |
| if (unlikely(!(file->f_mode & FMODE_WRITE))) |
| return -EBADF; |
| |
| ret = io_import_iovec(req->ctx, WRITE, s, &iovec, &iter); |
| if (ret < 0) |
| return ret; |
| |
| if (req->flags & REQ_F_LINK) |
| req->result = ret; |
| |
| iov_count = iov_iter_count(&iter); |
| |
| ret = -EAGAIN; |
| if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) { |
| /* If ->needs_lock is true, we're already in async context. */ |
| if (!s->needs_lock) |
| io_async_list_note(WRITE, req, iov_count); |
| goto out_free; |
| } |
| |
| 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) { |
| io_rw_done(kiocb, ret2); |
| } else { |
| /* |
| * If ->needs_lock is true, we're already in async |
| * context. |
| */ |
| if (!s->needs_lock) |
| io_async_list_note(WRITE, req, iov_count); |
| ret = -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, u64 user_data) |
| { |
| struct io_ring_ctx *ctx = req->ctx; |
| long err = 0; |
| |
| if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| |
| io_cqring_add_event(ctx, user_data, err); |
| 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, |
| 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->flags & REQ_F_LINK)) |
| req->flags |= REQ_F_FAIL_LINK; |
| io_cqring_add_event(req->ctx, sqe->user_data, ret); |
| io_put_req(req); |
| 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, |
| 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->flags & REQ_F_LINK)) |
| req->flags |= REQ_F_FAIL_LINK; |
| io_cqring_add_event(req->ctx, sqe->user_data, ret); |
| io_put_req(req); |
| return 0; |
| } |
| |
| #if defined(CONFIG_NET) |
| static int io_send_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| bool force_nonblock, |
| long (*fn)(struct socket *, struct user_msghdr __user *, |
| unsigned int)) |
| { |
| 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; |
| 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); |
| |
| ret = fn(sock, msg, flags); |
| if (force_nonblock && ret == -EAGAIN) |
| return ret; |
| } |
| |
| io_cqring_add_event(req->ctx, sqe->user_data, ret); |
| io_put_req(req); |
| return 0; |
| } |
| #endif |
| |
| static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| bool force_nonblock) |
| { |
| #if defined(CONFIG_NET) |
| return io_send_recvmsg(req, sqe, force_nonblock, __sys_sendmsg_sock); |
| #else |
| return -EOPNOTSUPP; |
| #endif |
| } |
| |
| static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe, |
| bool force_nonblock) |
| { |
| #if defined(CONFIG_NET) |
| return io_send_recvmsg(req, sqe, force_nonblock, __sys_recvmsg_sock); |
| #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->ctx, req); |
| } |
| spin_unlock(&poll->head->lock); |
| |
| list_del_init(&req->list); |
| } |
| |
| static void io_poll_remove_all(struct io_ring_ctx *ctx) |
| { |
| struct io_kiocb *req; |
| |
| spin_lock_irq(&ctx->completion_lock); |
| while (!list_empty(&ctx->cancel_list)) { |
| req = list_first_entry(&ctx->cancel_list, struct io_kiocb,list); |
| io_poll_remove_one(req); |
| } |
| spin_unlock_irq(&ctx->completion_lock); |
| } |
| |
| /* |
| * 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; |
| struct io_kiocb *poll_req, *next; |
| int ret = -ENOENT; |
| |
| 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); |
| list_for_each_entry_safe(poll_req, next, &ctx->cancel_list, list) { |
| if (READ_ONCE(sqe->addr) == poll_req->user_data) { |
| io_poll_remove_one(poll_req); |
| ret = 0; |
| break; |
| } |
| } |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| io_cqring_add_event(req->ctx, sqe->user_data, ret); |
| io_put_req(req); |
| return 0; |
| } |
| |
| static void io_poll_complete(struct io_ring_ctx *ctx, struct io_kiocb *req, |
| __poll_t mask) |
| { |
| req->poll.done = true; |
| io_cqring_fill_event(ctx, req->user_data, mangle_poll(mask)); |
| io_commit_cqring(ctx); |
| } |
| |
| static void io_poll_complete_work(struct work_struct *work) |
| { |
| 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; |
| __poll_t mask = 0; |
| |
| if (!READ_ONCE(poll->canceled)) |
| 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 && !READ_ONCE(poll->canceled)) { |
| add_wait_queue(poll->head, &poll->wait); |
| spin_unlock_irq(&ctx->completion_lock); |
| return; |
| } |
| list_del_init(&req->list); |
| io_poll_complete(ctx, req, mask); |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| io_cqring_ev_posted(ctx); |
| io_put_req(req); |
| } |
| |
| static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, |
| void *key) |
| { |
| struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb, |
| wait); |
| 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); |
| |
| if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) { |
| list_del(&req->list); |
| io_poll_complete(ctx, req, mask); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| |
| io_cqring_ev_posted(ctx); |
| io_put_req(req); |
| } else { |
| io_queue_async_work(ctx, 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 int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
| { |
| 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->submit.sqe = NULL; |
| INIT_WORK(&req->work, io_poll_complete_work); |
| events = READ_ONCE(sqe->poll_events); |
| poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP; |
| |
| 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); |
| |
| 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 */ |
| list_add_tail(&req->list, &ctx->cancel_list); |
| spin_unlock(&poll->head->lock); |
| } |
| if (mask) { /* no async, we'd stolen it */ |
| ipt.error = 0; |
| io_poll_complete(ctx, req, mask); |
| } |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| if (mask) { |
| io_cqring_ev_posted(ctx); |
| io_put_req(req); |
| } |
| return ipt.error; |
| } |
| |
| static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) |
| { |
| struct io_ring_ctx *ctx; |
| struct io_kiocb *req, *prev; |
| unsigned long flags; |
| |
| req = container_of(timer, struct io_kiocb, timeout.timer); |
| ctx = req->ctx; |
| atomic_inc(&ctx->cq_timeouts); |
| |
| spin_lock_irqsave(&ctx->completion_lock, flags); |
| /* |
| * Adjust the reqs sequence before the current one because it |
| * will consume a slot in the cq_ring and the 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(&req->list); |
| |
| io_cqring_fill_event(ctx, req->user_data, -ETIME); |
| io_commit_cqring(ctx); |
| spin_unlock_irqrestore(&ctx->completion_lock, flags); |
| |
| io_cqring_ev_posted(ctx); |
| |
| io_put_req(req); |
| return HRTIMER_NORESTART; |
| } |
| |
| static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
| { |
| unsigned count; |
| struct io_ring_ctx *ctx = req->ctx; |
| struct list_head *entry; |
| struct timespec64 ts; |
| unsigned span = 0; |
| |
| if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) |
| return -EINVAL; |
| if (sqe->flags || sqe->ioprio || sqe->buf_index || sqe->timeout_flags || |
| sqe->len != 1) |
| return -EINVAL; |
| |
| if (get_timespec64(&ts, u64_to_user_ptr(sqe->addr))) |
| return -EFAULT; |
| |
| /* |
| * sqe->off holds how many events that need to occur for this |
| * timeout event to be satisfied. |
| */ |
| count = READ_ONCE(sqe->off); |
| if (!count) |
| count = 1; |
| |
| req->sequence = ctx->cached_sq_head + count - 1; |
| /* reuse it to store the count */ |
| req->submit.sequence = count; |
| req->flags |= REQ_F_TIMEOUT; |
| |
| /* |
| * 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; |
| |
| /* |
| * 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->submit.sequence + 1; |
| tmp_nxt = (long long)nxt_sq_head + nxt->submit.sequence - 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; |
| list_add(&req->list, entry); |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| hrtimer_init(&req->timeout.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| req->timeout.timer.function = io_timeout_fn; |
| hrtimer_start(&req->timeout.timer, timespec64_to_ktime(ts), |
| HRTIMER_MODE_REL); |
| return 0; |
| } |
| |
| static int io_req_defer(struct io_ring_ctx *ctx, struct io_kiocb *req, |
| const struct io_uring_sqe *sqe) |
| { |
| struct io_uring_sqe *sqe_copy; |
| |
| if (!io_sequence_defer(ctx, req) && list_empty(&ctx->defer_list)) |
| return 0; |
| |
| sqe_copy = kmalloc(sizeof(*sqe_copy), GFP_KERNEL); |
| if (!sqe_copy) |
| return -EAGAIN; |
| |
| spin_lock_irq(&ctx->completion_lock); |
| if (!io_sequence_defer(ctx, req) && list_empty(&ctx->defer_list)) { |
| spin_unlock_irq(&ctx->completion_lock); |
| kfree(sqe_copy); |
| return 0; |
| } |
| |
| memcpy(sqe_copy, sqe, sizeof(*sqe_copy)); |
| req->submit.sqe = sqe_copy; |
| |
| INIT_WORK(&req->work, io_sq_wq_submit_work); |
| list_add_tail(&req->list, &ctx->defer_list); |
| spin_unlock_irq(&ctx->completion_lock); |
| return -EIOCBQUEUED; |
| } |
| |
| static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, |
| const struct sqe_submit *s, bool force_nonblock) |
| { |
| int ret, opcode; |
| |
| req->user_data = READ_ONCE(s->sqe->user_data); |
| |
| if (unlikely(s->index >= ctx->sq_entries)) |
| return -EINVAL; |
| |
| opcode = READ_ONCE(s->sqe->opcode); |
| switch (opcode) { |
| case IORING_OP_NOP: |
| ret = io_nop(req, req->user_data); |
| break; |
| case IORING_OP_READV: |
| if (unlikely(s->sqe->buf_index)) |
| return -EINVAL; |
| ret = io_read(req, s, force_nonblock); |
| break; |
| case IORING_OP_WRITEV: |
| if (unlikely(s->sqe->buf_index)) |
| return -EINVAL; |
| ret = io_write(req, s, force_nonblock); |
| break; |
| case IORING_OP_READ_FIXED: |
| ret = io_read(req, s, force_nonblock); |
| break; |
| case IORING_OP_WRITE_FIXED: |
| ret = io_write(req, s, force_nonblock); |
| break; |
| case IORING_OP_FSYNC: |
| ret = io_fsync(req, s->sqe, force_nonblock); |
| break; |
| case IORING_OP_POLL_ADD: |
| ret = io_poll_add(req, s->sqe); |
| break; |
| case IORING_OP_POLL_REMOVE: |
| ret = io_poll_remove(req, s->sqe); |
| break; |
| case IORING_OP_SYNC_FILE_RANGE: |
| ret = io_sync_file_range(req, s->sqe, force_nonblock); |
| break; |
| case IORING_OP_SENDMSG: |
| ret = io_sendmsg(req, s->sqe, force_nonblock); |
| break; |
| case IORING_OP_RECVMSG: |
| ret = io_recvmsg(req, s->sqe, force_nonblock); |
| break; |
| case IORING_OP_TIMEOUT: |
| ret = io_timeout(req, s->sqe); |
| break; |
| default: |
| ret = -EINVAL; |
| break; |
| } |
| |
| if (ret) |
| return ret; |
| |
| if (ctx->flags & IORING_SETUP_IOPOLL) { |
| if (req->result == -EAGAIN) |
| return -EAGAIN; |
| |
| /* workqueue context doesn't hold uring_lock, grab it now */ |
| if (s->needs_lock) |
| mutex_lock(&ctx->uring_lock); |
| io_iopoll_req_issued(req); |
| if (s->needs_lock) |
| mutex_unlock(&ctx->uring_lock); |
| } |
| |
| return 0; |
| } |
| |
| static struct async_list *io_async_list_from_sqe(struct io_ring_ctx *ctx, |
| const struct io_uring_sqe *sqe) |
| { |
| switch (sqe->opcode) { |
| case IORING_OP_READV: |
| case IORING_OP_READ_FIXED: |
| return &ctx->pending_async[READ]; |
| case IORING_OP_WRITEV: |
| case IORING_OP_WRITE_FIXED: |
| return &ctx->pending_async[WRITE]; |
| default: |
| return NULL; |
| } |
| } |
| |
| 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 void io_sq_wq_submit_work(struct work_struct *work) |
| { |
| struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
| struct io_ring_ctx *ctx = req->ctx; |
| struct mm_struct *cur_mm = NULL; |
| struct async_list *async_list; |
| LIST_HEAD(req_list); |
| mm_segment_t old_fs; |
| int ret; |
| |
| async_list = io_async_list_from_sqe(ctx, req->submit.sqe); |
| restart: |
| do { |
| struct sqe_submit *s = &req->submit; |
| const struct io_uring_sqe *sqe = s->sqe; |
| unsigned int flags = req->flags; |
| |
| /* Ensure we clear previously set non-block flag */ |
| req->rw.ki_flags &= ~IOCB_NOWAIT; |
| |
| ret = 0; |
| if (io_sqe_needs_user(sqe) && !cur_mm) { |
| if (!mmget_not_zero(ctx->sqo_mm)) { |
| ret = -EFAULT; |
| } else { |
| cur_mm = ctx->sqo_mm; |
| use_mm(cur_mm); |
| old_fs = get_fs(); |
| set_fs(USER_DS); |
| } |
| } |
| |
| if (!ret) { |
| s->has_user = cur_mm != NULL; |
| s->needs_lock = true; |
| do { |
| ret = __io_submit_sqe(ctx, req, s, 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) { |
| io_cqring_add_event(ctx, sqe->user_data, ret); |
| io_put_req(req); |
| } |
| |
| /* async context always use a copy of the sqe */ |
| kfree(sqe); |
| |
| /* req from defer and link list needn't decrease async cnt */ |
| if (flags & (REQ_F_IO_DRAINED | REQ_F_LINK_DONE)) |
| goto out; |
| |
| if (!async_list) |
| break; |
| if (!list_empty(&req_list)) { |
| req = list_first_entry(&req_list, struct io_kiocb, |
| list); |
| list_del(&req->list); |
| continue; |
| } |
| if (list_empty(&async_list->list)) |
| break; |
| |
| req = NULL; |
| spin_lock(&async_list->lock); |
| if (list_empty(&async_list->list)) { |
| spin_unlock(&async_list->lock); |
| break; |
| } |
| list_splice_init(&async_list->list, &req_list); |
| spin_unlock(&async_list->lock); |
| |
| req = list_first_entry(&req_list, struct io_kiocb, list); |
| list_del(&req->list); |
| } while (req); |
| |
| /* |
| * Rare case of racing with a submitter. If we find the count has |
| * dropped to zero AND we have pending work items, then restart |
| * the processing. This is a tiny race window. |
| */ |
| if (async_list) { |
| ret = atomic_dec_return(&async_list->cnt); |
| while (!ret && !list_empty(&async_list->list)) { |
| spin_lock(&async_list->lock); |
| atomic_inc(&async_list->cnt); |
| list_splice_init(&async_list->list, &req_list); |
| spin_unlock(&async_list->lock); |
| |
| if (!list_empty(&req_list)) { |
| req = list_first_entry(&req_list, |
| struct io_kiocb, list); |
| list_del(&req->list); |
| goto restart; |
| } |
| ret = atomic_dec_return(&async_list->cnt); |
| } |
| } |
| |
| out: |
| if (cur_mm) { |
| set_fs(old_fs); |
| unuse_mm(cur_mm); |
| mmput(cur_mm); |
| } |
| } |
| |
| /* |
| * See if we can piggy back onto previously submitted work, that is still |
| * running. We currently only allow this if the new request is sequential |
| * to the previous one we punted. |
| */ |
| static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb *req) |
| { |
| bool ret; |
| |
| if (!list) |
| return false; |
| if (!(req->flags & REQ_F_SEQ_PREV)) |
| return false; |
| if (!atomic_read(&list->cnt)) |
| return false; |
| |
| ret = true; |
| spin_lock(&list->lock); |
| list_add_tail(&req->list, &list->list); |
| /* |
| * Ensure we see a simultaneous modification from io_sq_wq_submit_work() |
| */ |
| smp_mb(); |
| if (!atomic_read(&list->cnt)) { |
| list_del_init(&req->list); |
| ret = false; |
| } |
| spin_unlock(&list->lock); |
| return ret; |
| } |
| |
| static bool 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: |
| return false; |
| default: |
| return true; |
| } |
| } |
| |
| static int io_req_set_file(struct io_ring_ctx *ctx, const struct sqe_submit *s, |
| struct io_submit_state *state, struct io_kiocb *req) |
| { |
| unsigned flags; |
| int fd; |
| |
| flags = READ_ONCE(s->sqe->flags); |
| fd = READ_ONCE(s->sqe->fd); |
| |
| if (flags & IOSQE_IO_DRAIN) |
| req->flags |= REQ_F_IO_DRAIN; |
| /* |
| * 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 = s->sequence; |
| |
| if (!io_op_needs_file(s->sqe)) |
| return 0; |
| |
| if (flags & IOSQE_FIXED_FILE) { |
| if (unlikely(!ctx->user_files || |
| (unsigned) fd >= ctx->nr_user_files)) |
| return -EBADF; |
| req->file = ctx->user_files[fd]; |
| req->flags |= REQ_F_FIXED_FILE; |
| } else { |
| if (s->needs_fixed_file) |
| return -EBADF; |
| req->file = io_file_get(state, fd); |
| if (unlikely(!req->file)) |
| return -EBADF; |
| } |
| |
| return 0; |
| } |
| |
| static int __io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, |
| struct sqe_submit *s) |
| { |
| int ret; |
| |
| ret = __io_submit_sqe(ctx, req, s, 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))) { |
| struct io_uring_sqe *sqe_copy; |
| |
| sqe_copy = kmemdup(s->sqe, sizeof(*sqe_copy), GFP_KERNEL); |
| if (sqe_copy) { |
| struct async_list *list; |
| |
| s->sqe = sqe_copy; |
| memcpy(&req->submit, s, sizeof(*s)); |
| list = io_async_list_from_sqe(ctx, s->sqe); |
| if (!io_add_to_prev_work(list, req)) { |
| if (list) |
| atomic_inc(&list->cnt); |
| INIT_WORK(&req->work, io_sq_wq_submit_work); |
| io_queue_async_work(ctx, req); |
| } |
| |
| /* |
| * Queued up for async execution, worker will release |
| * submit reference when the iocb is actually submitted. |
| */ |
| return 0; |
| } |
| } |
| |
| /* drop submission reference */ |
| io_put_req(req); |
| |
| /* and drop final reference, if we failed */ |
| if (ret) { |
| io_cqring_add_event(ctx, req->user_data, ret); |
| if (req->flags & REQ_F_LINK) |
| req->flags |= REQ_F_FAIL_LINK; |
| io_put_req(req); |
| } |
| |
| return ret; |
| } |
| |
| static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, |
| struct sqe_submit *s) |
| { |
| int ret; |
| |
| ret = io_req_defer(ctx, req, s->sqe); |
| if (ret) { |
| if (ret != -EIOCBQUEUED) { |
| io_free_req(req); |
| io_cqring_add_event(ctx, s->sqe->user_data, ret); |
| } |
| return 0; |
| } |
| |
| return __io_queue_sqe(ctx, req, s); |
| } |
| |
| static int io_queue_link_head(struct io_ring_ctx *ctx, struct io_kiocb *req, |
| struct sqe_submit *s, struct io_kiocb *shadow) |
| { |
| int ret; |
| int need_submit = false; |
| |
| if (!shadow) |
| return io_queue_sqe(ctx, req, s); |
| |
| /* |
| * Mark the first IO in link list as DRAIN, let all the following |
| * IOs enter the defer list. all IO needs to be completed before link |
| * list. |
| */ |
| req->flags |= REQ_F_IO_DRAIN; |
| ret = io_req_defer(ctx, req, s->sqe); |
| if (ret) { |
| if (ret != -EIOCBQUEUED) { |
| io_free_req(req); |
| io_cqring_add_event(ctx, s->sqe->user_data, ret); |
| return 0; |
| } |
| } else { |
| /* |
| * If ret == 0 means that all IOs in front of link io are |
| * running done. let's queue link head. |
| */ |
| need_submit = true; |
| } |
| |
| /* Insert shadow req to defer_list, blocking next IOs */ |
| spin_lock_irq(&ctx->completion_lock); |
| list_add_tail(&shadow->list, &ctx->defer_list); |
| spin_unlock_irq(&ctx->completion_lock); |
| |
| if (need_submit) |
| return __io_queue_sqe(ctx, req, s); |
| |
| return 0; |
| } |
| |
| #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK) |
| |
| static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s, |
| struct io_submit_state *state, struct io_kiocb **link) |
| { |
| struct io_uring_sqe *sqe_copy; |
| struct io_kiocb *req; |
| int ret; |
| |
| /* enforce forwards compatibility on users */ |
| if (unlikely(s->sqe->flags & ~SQE_VALID_FLAGS)) { |
| ret = -EINVAL; |
| goto err; |
| } |
| |
| req = io_get_req(ctx, state); |
| if (unlikely(!req)) { |
| ret = -EAGAIN; |
| goto err; |
| } |
| |
| ret = io_req_set_file(ctx, s, state, req); |
| if (unlikely(ret)) { |
| err_req: |
| io_free_req(req); |
| err: |
| io_cqring_add_event(ctx, s->sqe->user_data, ret); |
| return; |
| } |
| |
| req->user_data = s->sqe->user_data; |
| |
| /* |
| * 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; |
| |
| sqe_copy = kmemdup(s->sqe, sizeof(*sqe_copy), GFP_KERNEL); |
| if (!sqe_copy) { |
| ret = -EAGAIN; |
| goto err_req; |
| } |
| |
| s->sqe = sqe_copy; |
| memcpy(&req->submit, s, sizeof(*s)); |
| list_add_tail(&req->list, &prev->link_list); |
| } else if (s->sqe->flags & IOSQE_IO_LINK) { |
| req->flags |= REQ_F_LINK; |
| |
| memcpy(&req->submit, s, sizeof(*s)); |
| INIT_LIST_HEAD(&req->link_list); |
| *link = req; |
| } else { |
| io_queue_sqe(ctx, req, s); |
| } |
| } |
| |
| /* |
| * 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, |
| struct io_ring_ctx *ctx, unsigned 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 s->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 sqe_submit *s) |
| { |
| 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 (head == smp_load_acquire(&rings->sq.tail)) |
| return false; |
| |
| head = READ_ONCE(sq_array[head & ctx->sq_mask]); |
| if (head < ctx->sq_entries) { |
| s->index = head; |
| s->sqe = &ctx->sq_sqes[head]; |
| s->sequence = ctx->cached_sq_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, |
| bool has_user, bool mm_fault) |
| { |
| struct io_submit_state state, *statep = NULL; |
| struct io_kiocb *link = NULL; |
| struct io_kiocb *shadow_req = NULL; |
| bool prev_was_link = false; |
| int i, submitted = 0; |
| |
| if (nr > IO_PLUG_THRESHOLD) { |
| io_submit_state_start(&state, ctx, nr); |
| statep = &state; |
| } |
| |
| for (i = 0; i < nr; i++) { |
| struct sqe_submit s; |
| |
| if (!io_get_sqring(ctx, &s)) |
| break; |
| |
| /* |
| * If previous wasn't linked and we have a linked command, |
| * that's the end of the chain. Submit the previous link. |
| */ |
| if (!prev_was_link && link) { |
| io_queue_link_head(ctx, link, &link->submit, shadow_req); |
| link = NULL; |
| shadow_req = NULL; |
| } |
| prev_was_link = (s.sqe->flags & IOSQE_IO_LINK) != 0; |
| |
| if (link && (s.sqe->flags & IOSQE_IO_DRAIN)) { |
| if (!shadow_req) { |
| shadow_req = io_get_req(ctx, NULL); |
| if (unlikely(!shadow_req)) |
| goto out; |
| shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN); |
| refcount_dec(&shadow_req->refs); |
| } |
| shadow_req->sequence = s.sequence; |
| } |
| |
| out: |
| if (unlikely(mm_fault)) { |
| io_cqring_add_event(ctx, s.sqe->user_data, |
| -EFAULT); |
| } else { |
| s.has_user = has_user; |
| s.needs_lock = true; |
| s.needs_fixed_file = true; |
| io_submit_sqe(ctx, &s, statep, &link); |
| submitted++; |
| } |
| } |
| |
| if (link) |
| io_queue_link_head(ctx, link, &link->submit, shadow_req); |
| if (statep) |
| io_submit_state_end(&state); |
| |
| return submitted; |
| } |
| |
| static int io_sq_thread(void *data) |
| { |
| struct io_ring_ctx *ctx = data; |
| struct mm_struct *cur_mm = NULL; |
| mm_segment_t old_fs; |
| DEFINE_WAIT(wait); |
| unsigned inflight; |
| unsigned long timeout; |
| |
| complete(&ctx->sqo_thread_started); |
| |
| old_fs = get_fs(); |
| set_fs(USER_DS); |
| |
| timeout = inflight = 0; |
| while (!kthread_should_park()) { |
| bool mm_fault = false; |
| 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 (!to_submit) { |
| /* |
| * We're polling. If we're within the defined idle |
| * period, then let us spin without work before going |
| * to sleep. |
| */ |
| if (inflight || !time_after(jiffies, timeout)) { |
| 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) { |
| 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; |
| } |
| |
| /* Unless all new commands are FIXED regions, grab mm */ |
| if (!cur_mm) { |
| mm_fault = !mmget_not_zero(ctx->sqo_mm); |
| if (!mm_fault) { |
| use_mm(ctx->sqo_mm); |
| cur_mm = ctx->sqo_mm; |
| } |
| } |
| |
| to_submit = min(to_submit, ctx->sq_entries); |
| inflight += io_submit_sqes(ctx, to_submit, cur_mm != NULL, |
| mm_fault); |
| |
| /* Commit SQ ring head once we've consumed all SQEs */ |
| io_commit_sqring(ctx); |
| } |
| |
| set_fs(old_fs); |
| if (cur_mm) { |
| unuse_mm(cur_mm); |
| mmput(cur_mm); |
| } |
| |
| kthread_parkme(); |
| |
| return 0; |
| } |
| |
| static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit) |
| { |
| struct io_submit_state state, *statep = NULL; |
| struct io_kiocb *link = NULL; |
| struct io_kiocb *shadow_req = NULL; |
| bool prev_was_link = false; |
| int i, submit = 0; |
| |
| if (to_submit > IO_PLUG_THRESHOLD) { |
| io_submit_state_start(&state, ctx, to_submit); |
| statep = &state; |
| } |
| |
| for (i = 0; i < to_submit; i++) { |
| struct sqe_submit s; |
| |
| if (!io_get_sqring(ctx, &s)) |
| break; |
| |
| /* |
| * If previous wasn't linked and we have a linked command, |
| * that's the end of the chain. Submit the previous link. |
| */ |
| if (!prev_was_link && link) { |
| io_queue_link_head(ctx, link, &link->submit, shadow_req); |
| link = NULL; |
| shadow_req = NULL; |
| } |
| prev_was_link = (s.sqe->flags & IOSQE_IO_LINK) != 0; |
| |
| if (link && (s.sqe->flags & IOSQE_IO_DRAIN)) { |
| if (!shadow_req) { |
| shadow_req = io_get_req(ctx, NULL); |
| if (unlikely(!shadow_req)) |
| goto out; |
| shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN); |
| refcount_dec(&shadow_req->refs); |
| } |
| shadow_req->sequence = s.sequence; |
| } |
| |
| out: |
| s.has_user = true; |
| s.needs_lock = false; |
| s.needs_fixed_file = false; |
| submit++; |
| io_submit_sqe(ctx, &s, statep, &link); |
| } |
| |
| if (link) |
| io_queue_link_head(ctx, link, &link->submit, shadow_req); |
| if (statep) |
| io_submit_state_end(statep); |
| |
| io_commit_sqring(ctx); |
| |
| return submit; |
| } |
| |
| 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) |
| { |
| struct io_ring_ctx *ctx = iowq->ctx; |
| |
| /* |
| * Wake up if we have enough events, or if a timeout occured since we |
| * started waiting. For timeouts, we always want to return to userspace, |
| * regardless of event count. |
| */ |
| return io_cqring_events(ctx->rings) >= 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); |
| |
| if (!io_should_wake(iowq)) |
| 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; |
| |
| if (io_cqring_events(rings) >= 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; |
| } |
| |
| ret = 0; |
| iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); |
| do { |
| prepare_to_wait_exclusive(&ctx->wait, &iowq.wq, |
| TASK_INTERRUPTIBLE); |
| if (io_should_wake(&iowq)) |
| break; |
| schedule(); |
| if (signal_pending(current)) { |
| ret = -ERESTARTSYS; |
| break; |
| } |
| } while (1); |
| finish_wait(&ctx->wait, &iowq.wq); |
| |
| restore_saved_sigmask_unless(ret == -ERESTARTSYS); |
| if (ret == -ERESTARTSYS) |
| 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++) |
| fput(ctx->user_files[i]); |
| #endif |
| } |
| |
| static int io_sqe_files_unregister(struct io_ring_ctx *ctx) |
| { |
| if (!ctx->user_files) |
| return -ENXIO; |
| |
| __io_sqe_files_unregister(ctx); |
| kfree(ctx->user_files); |
| ctx->user_files = 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->sqo_thread_started); |
| /* |
| * 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) |
| { |
| int i; |
| |
| io_sq_thread_stop(ctx); |
| |
| for (i = 0; i < ARRAY_SIZE(ctx->sqo_wq); i++) { |
| if (ctx->sqo_wq[i]) { |
| destroy_workqueue(ctx->sqo_wq[i]); |
| ctx->sqo_wq[i] = NULL; |
| } |
| } |
| } |
| |
| #if defined(CONFIG_UNIX) |
| static void io_destruct_skb(struct sk_buff *skb) |
| { |
| struct io_ring_ctx *ctx = skb->sk->sk_user_data; |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(ctx->sqo_wq); i++) |
| if (ctx->sqo_wq[i]) |
| flush_workqueue(ctx->sqo_wq[i]); |
| |
| 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; |
| |
| 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; |
| skb->destructor = io_destruct_skb; |
| |
| fpl->user = get_uid(ctx->user); |
| for (i = 0; i < nr; i++) { |
| fpl->fp[i] = get_file(ctx->user_files[i + offset]); |
| unix_inflight(fpl->user, fpl->fp[i]); |
| } |
| |
| fpl->max = fpl->count = nr; |
| UNIXCB(skb).fp = fpl; |
| refcount_add(skb->truesize, &sk->sk_wmem_alloc); |
| skb_queue_head(&sk->sk_receive_queue, skb); |
| |
| for (i = 0; i < nr; i++) |
| fput(fpl->fp[i]); |
| |
| 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) { |
| fput(ctx->user_files[total]); |
| total++; |
| } |
| |
| return ret; |
| } |
| #else |
| static int io_sqe_files_scm(struct io_ring_ctx *ctx) |
| { |
| return 0; |
| } |
| #endif |
| |
| static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, |
| unsigned nr_args) |
| { |
| __s32 __user *fds = (__s32 __user *) arg; |
| int fd, ret = 0; |
| unsigned i; |
| |
| if (ctx->user_files) |
| return -EBUSY; |
| if (!nr_args) |
| return -EINVAL; |
| if (nr_args > IORING_MAX_FIXED_FILES) |
| return -EMFILE; |
| |
| ctx->user_files = kcalloc(nr_args, sizeof(struct file *), GFP_KERNEL); |
| if (!ctx->user_files) |
| return -ENOMEM; |
| |
| for (i = 0; i < nr_args; i++) { |
| ret = -EFAULT; |
| if (copy_from_user(&fd, &fds[i], sizeof(fd))) |
| break; |
| |
| ctx->user_files[i] = fget(fd); |
| |
| ret = -EBADF; |
| if (!ctx->user_files[i]) |
| 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 (ctx->user_files[i]->f_op == &io_uring_fops) { |
| fput(ctx->user_files[i]); |
| break; |
| } |
| ctx->nr_user_files++; |
| ret = 0; |
| } |
| |
| if (ret) { |
| for (i = 0; i < ctx->nr_user_files; i++) |
| fput(ctx->user_files[i]); |
| |
| kfree(ctx->user_files); |
| ctx->user_files = NULL; |
| ctx->nr_user_files = 0; |
| return ret; |
| } |
| |
| ret = io_sqe_files_scm(ctx); |
| if (ret) |
| io_sqe_files_unregister(ctx); |
| |
| return ret; |
| } |
| |
| static int io_sq_offload_start(struct io_ring_ctx *ctx, |
| struct io_uring_params *p) |
| { |
| 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; |
| } |
| |
| /* Do QD, or 2 * CPUS, whatever is smallest */ |
| ctx->sqo_wq[0] = alloc_workqueue("io_ring-wq", |
| WQ_UNBOUND | WQ_FREEZABLE, |
| min(ctx->sq_entries - 1, 2 * num_online_cpus())); |
| if (!ctx->sqo_wq[0]) { |
| ret = -ENOMEM; |
| goto err; |
| } |
| |
| /* |
| * This is for buffered writes, where we want to limit the parallelism |
| * due to file locking in file systems. As "normal" buffered writes |
| * should parellelize on writeout quite nicely, limit us to having 2 |
| * pending. This avoids massive contention on the inode when doing |
| * buffered async writes. |
| */ |
| ctx->sqo_wq[1] = alloc_workqueue("io_ring-write-wq", |
| WQ_UNBOUND | WQ_FREEZABLE, 2); |
| if (!ctx->sqo_wq[1]) { |
| ret = -ENOMEM; |
| 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); |
| 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); |
| io_iopoll_reap_events(ctx); |
| wait_for_completion(&ctx->ctx_done); |
| 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 int io_uring_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| loff_t offset = (loff_t) vma->vm_pgoff << PAGE_SHIFT; |
| unsigned long sz = vma->vm_end - vma->vm_start; |
| struct io_ring_ctx *ctx = file->private_data; |
| unsigned long pfn; |
| 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 -EINVAL; |
| } |
| |
| page = virt_to_head_page(ptr); |
| if (sz > page_size(page)) |
| return -EINVAL; |
| |
| pfn = virt_to_phys(ptr) >> PAGE_SHIFT; |
| return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); |
| } |
| |
| 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 (flags & IORING_ENTER_SQ_WAKEUP) |
| wake_up(&ctx->sqo_wait); |
| submitted = to_submit; |
| } else if (to_submit) { |
| to_submit = min(to_submit, ctx->sq_entries); |
| |
| mutex_lock(&ctx->uring_lock); |
| submitted = io_ring_submit(ctx, to_submit); |
| 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, |
| .mmap = io_uring_mmap, |
| .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) |
| return -EOVERFLOW; |
| |
| ctx->sq_sqes = io_mem_alloc(size); |
| if (!ctx->sq_sqes) |
| 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. |
| */ |
| p->sq_entries = roundup_pow_of_two(entries); |
| 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; |
| |
| ret = io_allocate_scq_urings(ctx, p); |
| if (ret) |
| goto err; |
| |
| ret = io_sq_offload_start(ctx, p); |
| if (ret) |
| goto err; |
| |
| ret = io_uring_get_fd(ctx); |
| if (ret < 0) |
| 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); |
| |
| p->features = IORING_FEAT_SINGLE_MMAP; |
| 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)) |
| 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->ctx_done); |
| 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_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->ctx_done); |
| 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); |
| 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); |