blob: cd6dcf634ba3cdea8f97bd94a6aac7f96550fb85 [file] [log] [blame]
Jens Axboe36404b02022-05-25 06:42:08 -06001// SPDX-License-Identifier: GPL-2.0
2#include <linux/kernel.h>
3#include <linux/errno.h>
4#include <linux/file.h>
5#include <linux/slab.h>
Jens Axboee6130eb2022-06-13 04:47:02 -06006#include <linux/nospec.h>
Jens Axboe36404b02022-05-25 06:42:08 -06007#include <linux/io_uring.h>
8
9#include <uapi/linux/io_uring.h>
10
Jens Axboe36404b02022-05-25 06:42:08 -060011#include "io_uring.h"
Jens Axboee6130eb2022-06-13 04:47:02 -060012#include "rsrc.h"
13#include "filetable.h"
Jens Axboe36404b02022-05-25 06:42:08 -060014#include "msg_ring.h"
15
Breno Leitaocbeb47a2023-01-03 08:05:07 -080016
17/* All valid masks for MSG_RING */
18#define IORING_MSG_RING_MASK (IORING_MSG_RING_CQE_SKIP | \
19 IORING_MSG_RING_FLAGS_PASS)
20
Jens Axboe36404b02022-05-25 06:42:08 -060021struct io_msg {
22 struct file *file;
Pavel Begunkov11373022022-12-07 03:53:34 +000023 struct file *src_file;
Pavel Begunkov6d043ee2022-12-07 03:53:36 +000024 struct callback_head tw;
Jens Axboe36404b02022-05-25 06:42:08 -060025 u64 user_data;
26 u32 len;
Jens Axboee6130eb2022-06-13 04:47:02 -060027 u32 cmd;
28 u32 src_fd;
Breno Leitaocbeb47a2023-01-03 08:05:07 -080029 union {
30 u32 dst_fd;
31 u32 cqe_flags;
32 };
Jens Axboee6130eb2022-06-13 04:47:02 -060033 u32 flags;
Jens Axboe36404b02022-05-25 06:42:08 -060034};
35
Jens Axboe423d5082023-01-19 09:01:27 -070036static void io_double_unlock_ctx(struct io_ring_ctx *octx)
37{
38 mutex_unlock(&octx->uring_lock);
39}
40
41static int io_double_lock_ctx(struct io_ring_ctx *octx,
42 unsigned int issue_flags)
43{
44 /*
45 * To ensure proper ordering between the two ctxs, we can only
46 * attempt a trylock on the target. If that fails and we already have
47 * the source ctx lock, punt to io-wq.
48 */
49 if (!(issue_flags & IO_URING_F_UNLOCKED)) {
50 if (!mutex_trylock(&octx->uring_lock))
51 return -EAGAIN;
52 return 0;
53 }
54 mutex_lock(&octx->uring_lock);
55 return 0;
56}
57
Pavel Begunkov11373022022-12-07 03:53:34 +000058void io_msg_ring_cleanup(struct io_kiocb *req)
59{
60 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
61
62 if (WARN_ON_ONCE(!msg->src_file))
63 return;
64
65 fput(msg->src_file);
66 msg->src_file = NULL;
67}
68
Pavel Begunkov56d8e312023-01-20 16:38:05 +000069static inline bool io_msg_need_remote(struct io_ring_ctx *target_ctx)
70{
71 if (!target_ctx->task_complete)
72 return false;
73 return current != target_ctx->submitter_task;
74}
75
76static int io_msg_exec_remote(struct io_kiocb *req, task_work_func_t func)
77{
78 struct io_ring_ctx *ctx = req->file->private_data;
79 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
Pavel Begunkov85795382023-01-20 16:38:06 +000080 struct task_struct *task = READ_ONCE(ctx->submitter_task);
81
82 if (unlikely(!task))
83 return -EOWNERDEAD;
Pavel Begunkov56d8e312023-01-20 16:38:05 +000084
85 init_task_work(&msg->tw, func);
86 if (task_work_add(ctx->submitter_task, &msg->tw, TWA_SIGNAL))
87 return -EOWNERDEAD;
88
89 return IOU_ISSUE_SKIP_COMPLETE;
90}
91
Pavel Begunkov6d043ee2022-12-07 03:53:36 +000092static void io_msg_tw_complete(struct callback_head *head)
93{
94 struct io_msg *msg = container_of(head, struct io_msg, tw);
95 struct io_kiocb *req = cmd_to_io_kiocb(msg);
96 struct io_ring_ctx *target_ctx = req->file->private_data;
97 int ret = 0;
98
Jens Axboee12d7a42023-01-19 09:04:40 -070099 if (current->flags & PF_EXITING) {
Pavel Begunkov6d043ee2022-12-07 03:53:36 +0000100 ret = -EOWNERDEAD;
Jens Axboee12d7a42023-01-19 09:04:40 -0700101 } else {
Jens Axboe8572df92023-01-21 19:53:41 -0700102 u32 flags = 0;
103
104 if (msg->flags & IORING_MSG_RING_FLAGS_PASS)
105 flags = msg->cqe_flags;
106
Jens Axboee12d7a42023-01-19 09:04:40 -0700107 /*
108 * If the target ring is using IOPOLL mode, then we need to be
109 * holding the uring_lock for posting completions. Other ring
110 * types rely on the regular completion locking, which is
111 * handled while posting.
112 */
113 if (target_ctx->flags & IORING_SETUP_IOPOLL)
114 mutex_lock(&target_ctx->uring_lock);
Jens Axboe8572df92023-01-21 19:53:41 -0700115 if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))
Jens Axboee12d7a42023-01-19 09:04:40 -0700116 ret = -EOVERFLOW;
117 if (target_ctx->flags & IORING_SETUP_IOPOLL)
118 mutex_unlock(&target_ctx->uring_lock);
119 }
Pavel Begunkov6d043ee2022-12-07 03:53:36 +0000120
121 if (ret < 0)
122 req_set_fail(req);
123 io_req_queue_tw_complete(req, ret);
124}
125
Jens Axboee12d7a42023-01-19 09:04:40 -0700126static int io_msg_ring_data(struct io_kiocb *req, unsigned int issue_flags)
Jens Axboee6130eb2022-06-13 04:47:02 -0600127{
128 struct io_ring_ctx *target_ctx = req->file->private_data;
Stefan Metzmacherf2ccb5a2022-08-11 09:11:15 +0200129 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
Breno Leitaocbeb47a2023-01-03 08:05:07 -0800130 u32 flags = 0;
Jens Axboee12d7a42023-01-19 09:04:40 -0700131 int ret;
Jens Axboee6130eb2022-06-13 04:47:02 -0600132
Breno Leitaocbeb47a2023-01-03 08:05:07 -0800133 if (msg->src_fd || msg->flags & ~IORING_MSG_RING_FLAGS_PASS)
134 return -EINVAL;
135 if (!(msg->flags & IORING_MSG_RING_FLAGS_PASS) && msg->dst_fd)
Jens Axboee6130eb2022-06-13 04:47:02 -0600136 return -EINVAL;
Pavel Begunkov85795382023-01-20 16:38:06 +0000137 if (target_ctx->flags & IORING_SETUP_R_DISABLED)
138 return -EBADFD;
Jens Axboee6130eb2022-06-13 04:47:02 -0600139
Pavel Begunkov56d8e312023-01-20 16:38:05 +0000140 if (io_msg_need_remote(target_ctx))
141 return io_msg_exec_remote(req, io_msg_tw_complete);
Pavel Begunkov6d043ee2022-12-07 03:53:36 +0000142
Breno Leitaocbeb47a2023-01-03 08:05:07 -0800143 if (msg->flags & IORING_MSG_RING_FLAGS_PASS)
144 flags = msg->cqe_flags;
145
Jens Axboee12d7a42023-01-19 09:04:40 -0700146 ret = -EOVERFLOW;
147 if (target_ctx->flags & IORING_SETUP_IOPOLL) {
148 if (unlikely(io_double_lock_ctx(target_ctx, issue_flags)))
149 return -EAGAIN;
Breno Leitaocbeb47a2023-01-03 08:05:07 -0800150 if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))
Jens Axboee12d7a42023-01-19 09:04:40 -0700151 ret = 0;
152 io_double_unlock_ctx(target_ctx);
153 } else {
Breno Leitaocbeb47a2023-01-03 08:05:07 -0800154 if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, flags))
Jens Axboee12d7a42023-01-19 09:04:40 -0700155 ret = 0;
156 }
157 return ret;
Jens Axboee6130eb2022-06-13 04:47:02 -0600158}
159
Pavel Begunkov11373022022-12-07 03:53:34 +0000160static struct file *io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags)
161{
162 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
163 struct io_ring_ctx *ctx = req->ctx;
164 struct file *file = NULL;
Pavel Begunkov11373022022-12-07 03:53:34 +0000165 int idx = msg->src_fd;
166
167 io_ring_submit_lock(ctx, issue_flags);
168 if (likely(idx < ctx->nr_user_files)) {
169 idx = array_index_nospec(idx, ctx->nr_user_files);
Christoph Hellwigf432c8c2023-06-20 13:32:34 +0200170 file = io_file_from_index(&ctx->file_table, idx);
Pavel Begunkov11373022022-12-07 03:53:34 +0000171 if (file)
172 get_file(file);
173 }
174 io_ring_submit_unlock(ctx, issue_flags);
175 return file;
176}
177
Pavel Begunkov17211312022-12-07 03:53:35 +0000178static int io_msg_install_complete(struct io_kiocb *req, unsigned int issue_flags)
Jens Axboee6130eb2022-06-13 04:47:02 -0600179{
180 struct io_ring_ctx *target_ctx = req->file->private_data;
Stefan Metzmacherf2ccb5a2022-08-11 09:11:15 +0200181 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
Pavel Begunkov11373022022-12-07 03:53:34 +0000182 struct file *src_file = msg->src_file;
Jens Axboee6130eb2022-06-13 04:47:02 -0600183 int ret;
184
Pavel Begunkov11373022022-12-07 03:53:34 +0000185 if (unlikely(io_double_lock_ctx(target_ctx, issue_flags)))
186 return -EAGAIN;
Jens Axboee6130eb2022-06-13 04:47:02 -0600187
188 ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd);
Pavel Begunkov11373022022-12-07 03:53:34 +0000189 if (ret < 0)
Jens Axboee6130eb2022-06-13 04:47:02 -0600190 goto out_unlock;
Pavel Begunkov17211312022-12-07 03:53:35 +0000191
Pavel Begunkov11373022022-12-07 03:53:34 +0000192 msg->src_file = NULL;
193 req->flags &= ~REQ_F_NEED_CLEANUP;
Jens Axboee6130eb2022-06-13 04:47:02 -0600194
195 if (msg->flags & IORING_MSG_RING_CQE_SKIP)
196 goto out_unlock;
Jens Axboee6130eb2022-06-13 04:47:02 -0600197 /*
198 * If this fails, the target still received the file descriptor but
199 * wasn't notified of the fact. This means that if this request
200 * completes with -EOVERFLOW, then the sender must ensure that a
201 * later IORING_OP_MSG_RING delivers the message.
202 */
Pavel Begunkov5da28ed2023-03-16 12:11:42 +0000203 if (!io_post_aux_cqe(target_ctx, msg->user_data, ret, 0))
Jens Axboee6130eb2022-06-13 04:47:02 -0600204 ret = -EOVERFLOW;
205out_unlock:
Jens Axboe423d5082023-01-19 09:01:27 -0700206 io_double_unlock_ctx(target_ctx);
Jens Axboee6130eb2022-06-13 04:47:02 -0600207 return ret;
208}
209
Pavel Begunkov6d043ee2022-12-07 03:53:36 +0000210static void io_msg_tw_fd_complete(struct callback_head *head)
211{
212 struct io_msg *msg = container_of(head, struct io_msg, tw);
213 struct io_kiocb *req = cmd_to_io_kiocb(msg);
214 int ret = -EOWNERDEAD;
215
216 if (!(current->flags & PF_EXITING))
217 ret = io_msg_install_complete(req, IO_URING_F_UNLOCKED);
218 if (ret < 0)
219 req_set_fail(req);
220 io_req_queue_tw_complete(req, ret);
221}
222
Pavel Begunkov17211312022-12-07 03:53:35 +0000223static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
224{
225 struct io_ring_ctx *target_ctx = req->file->private_data;
226 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
227 struct io_ring_ctx *ctx = req->ctx;
228 struct file *src_file = msg->src_file;
229
Pavel Begunkov5da28ed2023-03-16 12:11:42 +0000230 if (msg->len)
231 return -EINVAL;
Pavel Begunkov17211312022-12-07 03:53:35 +0000232 if (target_ctx == ctx)
233 return -EINVAL;
Pavel Begunkov85795382023-01-20 16:38:06 +0000234 if (target_ctx->flags & IORING_SETUP_R_DISABLED)
235 return -EBADFD;
Pavel Begunkov17211312022-12-07 03:53:35 +0000236 if (!src_file) {
237 src_file = io_msg_grab_file(req, issue_flags);
238 if (!src_file)
239 return -EBADF;
240 msg->src_file = src_file;
241 req->flags |= REQ_F_NEED_CLEANUP;
242 }
Pavel Begunkov6d043ee2022-12-07 03:53:36 +0000243
Pavel Begunkov56d8e312023-01-20 16:38:05 +0000244 if (io_msg_need_remote(target_ctx))
245 return io_msg_exec_remote(req, io_msg_tw_fd_complete);
Pavel Begunkov17211312022-12-07 03:53:35 +0000246 return io_msg_install_complete(req, issue_flags);
247}
248
Jens Axboe36404b02022-05-25 06:42:08 -0600249int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
250{
Stefan Metzmacherf2ccb5a2022-08-11 09:11:15 +0200251 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
Jens Axboe36404b02022-05-25 06:42:08 -0600252
Jens Axboee6130eb2022-06-13 04:47:02 -0600253 if (unlikely(sqe->buf_index || sqe->personality))
Jens Axboe36404b02022-05-25 06:42:08 -0600254 return -EINVAL;
255
Pavel Begunkov11373022022-12-07 03:53:34 +0000256 msg->src_file = NULL;
Jens Axboe36404b02022-05-25 06:42:08 -0600257 msg->user_data = READ_ONCE(sqe->off);
258 msg->len = READ_ONCE(sqe->len);
Jens Axboee6130eb2022-06-13 04:47:02 -0600259 msg->cmd = READ_ONCE(sqe->addr);
260 msg->src_fd = READ_ONCE(sqe->addr3);
261 msg->dst_fd = READ_ONCE(sqe->file_index);
262 msg->flags = READ_ONCE(sqe->msg_ring_flags);
Breno Leitaocbeb47a2023-01-03 08:05:07 -0800263 if (msg->flags & ~IORING_MSG_RING_MASK)
Jens Axboee6130eb2022-06-13 04:47:02 -0600264 return -EINVAL;
265
Jens Axboe36404b02022-05-25 06:42:08 -0600266 return 0;
267}
268
269int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
270{
Stefan Metzmacherf2ccb5a2022-08-11 09:11:15 +0200271 struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
Jens Axboe36404b02022-05-25 06:42:08 -0600272 int ret;
273
274 ret = -EBADFD;
275 if (!io_is_uring_fops(req->file))
276 goto done;
277
Jens Axboee6130eb2022-06-13 04:47:02 -0600278 switch (msg->cmd) {
279 case IORING_MSG_DATA:
Jens Axboee12d7a42023-01-19 09:04:40 -0700280 ret = io_msg_ring_data(req, issue_flags);
Jens Axboee6130eb2022-06-13 04:47:02 -0600281 break;
282 case IORING_MSG_SEND_FD:
283 ret = io_msg_send_fd(req, issue_flags);
284 break;
285 default:
286 ret = -EINVAL;
287 break;
288 }
Jens Axboe36404b02022-05-25 06:42:08 -0600289
290done:
Pavel Begunkov6d043ee2022-12-07 03:53:36 +0000291 if (ret < 0) {
292 if (ret == -EAGAIN || ret == IOU_ISSUE_SKIP_COMPLETE)
293 return ret;
Jens Axboe36404b02022-05-25 06:42:08 -0600294 req_set_fail(req);
Pavel Begunkov6d043ee2022-12-07 03:53:36 +0000295 }
Jens Axboe36404b02022-05-25 06:42:08 -0600296 io_req_set_res(req, ret, 0);
Jens Axboe36404b02022-05-25 06:42:08 -0600297 return IOU_OK;
298}