1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/kernel.h> |
3 | #include <linux/errno.h> |
4 | #include <linux/fs.h> |
5 | #include <linux/file.h> |
6 | #include <linux/blk-mq.h> |
7 | #include <linux/mm.h> |
8 | #include <linux/slab.h> |
9 | #include <linux/fsnotify.h> |
10 | #include <linux/poll.h> |
11 | #include <linux/nospec.h> |
12 | #include <linux/compat.h> |
13 | #include <linux/io_uring/cmd.h> |
14 | #include <linux/indirect_call_wrapper.h> |
15 | |
16 | #include <uapi/linux/io_uring.h> |
17 | |
18 | #include "io_uring.h" |
19 | #include "opdef.h" |
20 | #include "kbuf.h" |
21 | #include "rsrc.h" |
22 | #include "poll.h" |
23 | #include "rw.h" |
24 | |
25 | struct io_rw { |
26 | /* NOTE: kiocb has the file as the first member, so don't do it here */ |
27 | struct kiocb kiocb; |
28 | u64 addr; |
29 | u32 len; |
30 | rwf_t flags; |
31 | }; |
32 | |
33 | static inline bool io_file_supports_nowait(struct io_kiocb *req) |
34 | { |
35 | return req->flags & REQ_F_SUPPORT_NOWAIT; |
36 | } |
37 | |
38 | #ifdef CONFIG_COMPAT |
39 | static int io_iov_compat_buffer_select_prep(struct io_rw *rw) |
40 | { |
41 | struct compat_iovec __user *uiov; |
42 | compat_ssize_t clen; |
43 | |
44 | uiov = u64_to_user_ptr(rw->addr); |
45 | if (!access_ok(uiov, sizeof(*uiov))) |
46 | return -EFAULT; |
47 | if (__get_user(clen, &uiov->iov_len)) |
48 | return -EFAULT; |
49 | if (clen < 0) |
50 | return -EINVAL; |
51 | |
52 | rw->len = clen; |
53 | return 0; |
54 | } |
55 | #endif |
56 | |
57 | static int io_iov_buffer_select_prep(struct io_kiocb *req) |
58 | { |
59 | struct iovec __user *uiov; |
60 | struct iovec iov; |
61 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
62 | |
63 | if (rw->len != 1) |
64 | return -EINVAL; |
65 | |
66 | #ifdef CONFIG_COMPAT |
67 | if (req->ctx->compat) |
68 | return io_iov_compat_buffer_select_prep(rw); |
69 | #endif |
70 | |
71 | uiov = u64_to_user_ptr(rw->addr); |
72 | if (copy_from_user(to: &iov, from: uiov, n: sizeof(*uiov))) |
73 | return -EFAULT; |
74 | rw->len = iov.iov_len; |
75 | return 0; |
76 | } |
77 | |
78 | int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
79 | { |
80 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
81 | unsigned ioprio; |
82 | int ret; |
83 | |
84 | rw->kiocb.ki_pos = READ_ONCE(sqe->off); |
85 | /* used for fixed read/write too - just read unconditionally */ |
86 | req->buf_index = READ_ONCE(sqe->buf_index); |
87 | |
88 | ioprio = READ_ONCE(sqe->ioprio); |
89 | if (ioprio) { |
90 | ret = ioprio_check_cap(ioprio); |
91 | if (ret) |
92 | return ret; |
93 | |
94 | rw->kiocb.ki_ioprio = ioprio; |
95 | } else { |
96 | rw->kiocb.ki_ioprio = get_current_ioprio(); |
97 | } |
98 | rw->kiocb.dio_complete = NULL; |
99 | |
100 | rw->addr = READ_ONCE(sqe->addr); |
101 | rw->len = READ_ONCE(sqe->len); |
102 | rw->flags = READ_ONCE(sqe->rw_flags); |
103 | return 0; |
104 | } |
105 | |
106 | int io_prep_rwv(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
107 | { |
108 | int ret; |
109 | |
110 | ret = io_prep_rw(req, sqe); |
111 | if (unlikely(ret)) |
112 | return ret; |
113 | |
114 | /* |
115 | * Have to do this validation here, as this is in io_read() rw->len |
116 | * might have chanaged due to buffer selection |
117 | */ |
118 | if (req->flags & REQ_F_BUFFER_SELECT) |
119 | return io_iov_buffer_select_prep(req); |
120 | |
121 | return 0; |
122 | } |
123 | |
124 | int io_prep_rw_fixed(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
125 | { |
126 | struct io_ring_ctx *ctx = req->ctx; |
127 | u16 index; |
128 | int ret; |
129 | |
130 | ret = io_prep_rw(req, sqe); |
131 | if (unlikely(ret)) |
132 | return ret; |
133 | |
134 | if (unlikely(req->buf_index >= ctx->nr_user_bufs)) |
135 | return -EFAULT; |
136 | index = array_index_nospec(req->buf_index, ctx->nr_user_bufs); |
137 | req->imu = ctx->user_bufs[index]; |
138 | io_req_set_rsrc_node(req, ctx, issue_flags: 0); |
139 | return 0; |
140 | } |
141 | |
142 | /* |
143 | * Multishot read is prepared just like a normal read/write request, only |
144 | * difference is that we set the MULTISHOT flag. |
145 | */ |
146 | int io_read_mshot_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
147 | { |
148 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
149 | int ret; |
150 | |
151 | /* must be used with provided buffers */ |
152 | if (!(req->flags & REQ_F_BUFFER_SELECT)) |
153 | return -EINVAL; |
154 | |
155 | ret = io_prep_rw(req, sqe); |
156 | if (unlikely(ret)) |
157 | return ret; |
158 | |
159 | if (rw->addr || rw->len) |
160 | return -EINVAL; |
161 | |
162 | req->flags |= REQ_F_APOLL_MULTISHOT; |
163 | return 0; |
164 | } |
165 | |
166 | void io_readv_writev_cleanup(struct io_kiocb *req) |
167 | { |
168 | struct io_async_rw *io = req->async_data; |
169 | |
170 | kfree(objp: io->free_iovec); |
171 | } |
172 | |
173 | static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req) |
174 | { |
175 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
176 | |
177 | if (rw->kiocb.ki_pos != -1) |
178 | return &rw->kiocb.ki_pos; |
179 | |
180 | if (!(req->file->f_mode & FMODE_STREAM)) { |
181 | req->flags |= REQ_F_CUR_POS; |
182 | rw->kiocb.ki_pos = req->file->f_pos; |
183 | return &rw->kiocb.ki_pos; |
184 | } |
185 | |
186 | rw->kiocb.ki_pos = 0; |
187 | return NULL; |
188 | } |
189 | |
190 | static void io_req_task_queue_reissue(struct io_kiocb *req) |
191 | { |
192 | req->io_task_work.func = io_queue_iowq; |
193 | io_req_task_work_add(req); |
194 | } |
195 | |
196 | #ifdef CONFIG_BLOCK |
197 | static bool io_resubmit_prep(struct io_kiocb *req) |
198 | { |
199 | struct io_async_rw *io = req->async_data; |
200 | |
201 | if (!req_has_async_data(req)) |
202 | return !io_req_prep_async(req); |
203 | iov_iter_restore(i: &io->s.iter, state: &io->s.iter_state); |
204 | return true; |
205 | } |
206 | |
207 | static bool io_rw_should_reissue(struct io_kiocb *req) |
208 | { |
209 | umode_t mode = file_inode(f: req->file)->i_mode; |
210 | struct io_ring_ctx *ctx = req->ctx; |
211 | |
212 | if (!S_ISBLK(mode) && !S_ISREG(mode)) |
213 | return false; |
214 | if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() && |
215 | !(ctx->flags & IORING_SETUP_IOPOLL))) |
216 | return false; |
217 | /* |
218 | * If ref is dying, we might be running poll reap from the exit work. |
219 | * Don't attempt to reissue from that path, just let it fail with |
220 | * -EAGAIN. |
221 | */ |
222 | if (percpu_ref_is_dying(ref: &ctx->refs)) |
223 | return false; |
224 | /* |
225 | * Play it safe and assume not safe to re-import and reissue if we're |
226 | * not in the original thread group (or in task context). |
227 | */ |
228 | if (!same_thread_group(p1: req->task, current) || !in_task()) |
229 | return false; |
230 | return true; |
231 | } |
232 | #else |
233 | static bool io_resubmit_prep(struct io_kiocb *req) |
234 | { |
235 | return false; |
236 | } |
237 | static bool io_rw_should_reissue(struct io_kiocb *req) |
238 | { |
239 | return false; |
240 | } |
241 | #endif |
242 | |
243 | static void io_req_end_write(struct io_kiocb *req) |
244 | { |
245 | if (req->flags & REQ_F_ISREG) { |
246 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
247 | |
248 | kiocb_end_write(iocb: &rw->kiocb); |
249 | } |
250 | } |
251 | |
252 | /* |
253 | * Trigger the notifications after having done some IO, and finish the write |
254 | * accounting, if any. |
255 | */ |
256 | static void io_req_io_end(struct io_kiocb *req) |
257 | { |
258 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
259 | |
260 | if (rw->kiocb.ki_flags & IOCB_WRITE) { |
261 | io_req_end_write(req); |
262 | fsnotify_modify(file: req->file); |
263 | } else { |
264 | fsnotify_access(file: req->file); |
265 | } |
266 | } |
267 | |
268 | static bool __io_complete_rw_common(struct io_kiocb *req, long res) |
269 | { |
270 | if (unlikely(res != req->cqe.res)) { |
271 | if ((res == -EAGAIN || res == -EOPNOTSUPP) && |
272 | io_rw_should_reissue(req)) { |
273 | /* |
274 | * Reissue will start accounting again, finish the |
275 | * current cycle. |
276 | */ |
277 | io_req_io_end(req); |
278 | req->flags |= REQ_F_REISSUE | REQ_F_BL_NO_RECYCLE; |
279 | return true; |
280 | } |
281 | req_set_fail(req); |
282 | req->cqe.res = res; |
283 | } |
284 | return false; |
285 | } |
286 | |
287 | static inline int io_fixup_rw_res(struct io_kiocb *req, long res) |
288 | { |
289 | struct io_async_rw *io = req->async_data; |
290 | |
291 | /* add previously done IO, if any */ |
292 | if (req_has_async_data(req) && io->bytes_done > 0) { |
293 | if (res < 0) |
294 | res = io->bytes_done; |
295 | else |
296 | res += io->bytes_done; |
297 | } |
298 | return res; |
299 | } |
300 | |
301 | void io_req_rw_complete(struct io_kiocb *req, struct io_tw_state *ts) |
302 | { |
303 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
304 | struct kiocb *kiocb = &rw->kiocb; |
305 | |
306 | if ((kiocb->ki_flags & IOCB_DIO_CALLER_COMP) && kiocb->dio_complete) { |
307 | long res = kiocb->dio_complete(rw->kiocb.private); |
308 | |
309 | io_req_set_res(req, res: io_fixup_rw_res(req, res), cflags: 0); |
310 | } |
311 | |
312 | io_req_io_end(req); |
313 | |
314 | if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) { |
315 | unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED; |
316 | |
317 | req->cqe.flags |= io_put_kbuf(req, issue_flags); |
318 | } |
319 | io_req_task_complete(req, ts); |
320 | } |
321 | |
322 | static void io_complete_rw(struct kiocb *kiocb, long res) |
323 | { |
324 | struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); |
325 | struct io_kiocb *req = cmd_to_io_kiocb(rw); |
326 | |
327 | if (!kiocb->dio_complete || !(kiocb->ki_flags & IOCB_DIO_CALLER_COMP)) { |
328 | if (__io_complete_rw_common(req, res)) |
329 | return; |
330 | io_req_set_res(req, res: io_fixup_rw_res(req, res), cflags: 0); |
331 | } |
332 | req->io_task_work.func = io_req_rw_complete; |
333 | __io_req_task_work_add(req, flags: IOU_F_TWQ_LAZY_WAKE); |
334 | } |
335 | |
336 | static void io_complete_rw_iopoll(struct kiocb *kiocb, long res) |
337 | { |
338 | struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); |
339 | struct io_kiocb *req = cmd_to_io_kiocb(rw); |
340 | |
341 | if (kiocb->ki_flags & IOCB_WRITE) |
342 | io_req_end_write(req); |
343 | if (unlikely(res != req->cqe.res)) { |
344 | if (res == -EAGAIN && io_rw_should_reissue(req)) { |
345 | req->flags |= REQ_F_REISSUE | REQ_F_BL_NO_RECYCLE; |
346 | return; |
347 | } |
348 | req->cqe.res = res; |
349 | } |
350 | |
351 | /* order with io_iopoll_complete() checking ->iopoll_completed */ |
352 | smp_store_release(&req->iopoll_completed, 1); |
353 | } |
354 | |
355 | static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) |
356 | { |
357 | /* IO was queued async, completion will happen later */ |
358 | if (ret == -EIOCBQUEUED) |
359 | return; |
360 | |
361 | /* transform internal restart error codes */ |
362 | if (unlikely(ret < 0)) { |
363 | switch (ret) { |
364 | case -ERESTARTSYS: |
365 | case -ERESTARTNOINTR: |
366 | case -ERESTARTNOHAND: |
367 | case -ERESTART_RESTARTBLOCK: |
368 | /* |
369 | * We can't just restart the syscall, since previously |
370 | * submitted sqes may already be in progress. Just fail |
371 | * this IO with EINTR. |
372 | */ |
373 | ret = -EINTR; |
374 | break; |
375 | } |
376 | } |
377 | |
378 | INDIRECT_CALL_2(kiocb->ki_complete, io_complete_rw_iopoll, |
379 | io_complete_rw, kiocb, ret); |
380 | } |
381 | |
382 | static int kiocb_done(struct io_kiocb *req, ssize_t ret, |
383 | unsigned int issue_flags) |
384 | { |
385 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
386 | unsigned final_ret = io_fixup_rw_res(req, res: ret); |
387 | |
388 | if (ret >= 0 && req->flags & REQ_F_CUR_POS) |
389 | req->file->f_pos = rw->kiocb.ki_pos; |
390 | if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) { |
391 | if (!__io_complete_rw_common(req, res: ret)) { |
392 | /* |
393 | * Safe to call io_end from here as we're inline |
394 | * from the submission path. |
395 | */ |
396 | io_req_io_end(req); |
397 | io_req_set_res(req, res: final_ret, |
398 | cflags: io_put_kbuf(req, issue_flags)); |
399 | return IOU_OK; |
400 | } |
401 | } else { |
402 | io_rw_done(kiocb: &rw->kiocb, ret); |
403 | } |
404 | |
405 | if (req->flags & REQ_F_REISSUE) { |
406 | req->flags &= ~REQ_F_REISSUE; |
407 | if (io_resubmit_prep(req)) |
408 | io_req_task_queue_reissue(req); |
409 | else |
410 | io_req_task_queue_fail(req, ret: final_ret); |
411 | } |
412 | return IOU_ISSUE_SKIP_COMPLETE; |
413 | } |
414 | |
415 | static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req, |
416 | struct io_rw_state *s, |
417 | unsigned int issue_flags) |
418 | { |
419 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
420 | struct iov_iter *iter = &s->iter; |
421 | u8 opcode = req->opcode; |
422 | struct iovec *iovec; |
423 | void __user *buf; |
424 | size_t sqe_len; |
425 | ssize_t ret; |
426 | |
427 | if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { |
428 | ret = io_import_fixed(ddir, iter, imu: req->imu, buf_addr: rw->addr, len: rw->len); |
429 | if (ret) |
430 | return ERR_PTR(error: ret); |
431 | return NULL; |
432 | } |
433 | |
434 | buf = u64_to_user_ptr(rw->addr); |
435 | sqe_len = rw->len; |
436 | |
437 | if (!io_issue_defs[opcode].vectored || req->flags & REQ_F_BUFFER_SELECT) { |
438 | if (io_do_buffer_select(req)) { |
439 | buf = io_buffer_select(req, len: &sqe_len, issue_flags); |
440 | if (!buf) |
441 | return ERR_PTR(error: -ENOBUFS); |
442 | rw->addr = (unsigned long) buf; |
443 | rw->len = sqe_len; |
444 | } |
445 | |
446 | ret = import_ubuf(type: ddir, buf, len: sqe_len, i: iter); |
447 | if (ret) |
448 | return ERR_PTR(error: ret); |
449 | return NULL; |
450 | } |
451 | |
452 | iovec = s->fast_iov; |
453 | ret = __import_iovec(type: ddir, uvec: buf, nr_segs: sqe_len, UIO_FASTIOV, iovp: &iovec, i: iter, |
454 | compat: req->ctx->compat); |
455 | if (unlikely(ret < 0)) |
456 | return ERR_PTR(error: ret); |
457 | return iovec; |
458 | } |
459 | |
460 | static inline int io_import_iovec(int rw, struct io_kiocb *req, |
461 | struct iovec **iovec, struct io_rw_state *s, |
462 | unsigned int issue_flags) |
463 | { |
464 | *iovec = __io_import_iovec(ddir: rw, req, s, issue_flags); |
465 | if (IS_ERR(ptr: *iovec)) |
466 | return PTR_ERR(ptr: *iovec); |
467 | |
468 | iov_iter_save_state(iter: &s->iter, state: &s->iter_state); |
469 | return 0; |
470 | } |
471 | |
472 | static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb) |
473 | { |
474 | return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos; |
475 | } |
476 | |
477 | /* |
478 | * For files that don't have ->read_iter() and ->write_iter(), handle them |
479 | * by looping over ->read() or ->write() manually. |
480 | */ |
481 | static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter) |
482 | { |
483 | struct kiocb *kiocb = &rw->kiocb; |
484 | struct file *file = kiocb->ki_filp; |
485 | ssize_t ret = 0; |
486 | loff_t *ppos; |
487 | |
488 | /* |
489 | * Don't support polled IO through this interface, and we can't |
490 | * support non-blocking either. For the latter, this just causes |
491 | * the kiocb to be handled from an async context. |
492 | */ |
493 | if (kiocb->ki_flags & IOCB_HIPRI) |
494 | return -EOPNOTSUPP; |
495 | if ((kiocb->ki_flags & IOCB_NOWAIT) && |
496 | !(kiocb->ki_filp->f_flags & O_NONBLOCK)) |
497 | return -EAGAIN; |
498 | |
499 | ppos = io_kiocb_ppos(kiocb); |
500 | |
501 | while (iov_iter_count(i: iter)) { |
502 | void __user *addr; |
503 | size_t len; |
504 | ssize_t nr; |
505 | |
506 | if (iter_is_ubuf(i: iter)) { |
507 | addr = iter->ubuf + iter->iov_offset; |
508 | len = iov_iter_count(i: iter); |
509 | } else if (!iov_iter_is_bvec(i: iter)) { |
510 | addr = iter_iov_addr(iter); |
511 | len = iter_iov_len(iter); |
512 | } else { |
513 | addr = u64_to_user_ptr(rw->addr); |
514 | len = rw->len; |
515 | } |
516 | |
517 | if (ddir == READ) |
518 | nr = file->f_op->read(file, addr, len, ppos); |
519 | else |
520 | nr = file->f_op->write(file, addr, len, ppos); |
521 | |
522 | if (nr < 0) { |
523 | if (!ret) |
524 | ret = nr; |
525 | break; |
526 | } |
527 | ret += nr; |
528 | if (!iov_iter_is_bvec(i: iter)) { |
529 | iov_iter_advance(i: iter, bytes: nr); |
530 | } else { |
531 | rw->addr += nr; |
532 | rw->len -= nr; |
533 | if (!rw->len) |
534 | break; |
535 | } |
536 | if (nr != len) |
537 | break; |
538 | } |
539 | |
540 | return ret; |
541 | } |
542 | |
543 | static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec, |
544 | const struct iovec *fast_iov, struct iov_iter *iter) |
545 | { |
546 | struct io_async_rw *io = req->async_data; |
547 | |
548 | memcpy(&io->s.iter, iter, sizeof(*iter)); |
549 | io->free_iovec = iovec; |
550 | io->bytes_done = 0; |
551 | /* can only be fixed buffers, no need to do anything */ |
552 | if (iov_iter_is_bvec(i: iter) || iter_is_ubuf(i: iter)) |
553 | return; |
554 | if (!iovec) { |
555 | unsigned iov_off = 0; |
556 | |
557 | io->s.iter.__iov = io->s.fast_iov; |
558 | if (iter->__iov != fast_iov) { |
559 | iov_off = iter_iov(iter) - fast_iov; |
560 | io->s.iter.__iov += iov_off; |
561 | } |
562 | if (io->s.fast_iov != fast_iov) |
563 | memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off, |
564 | sizeof(struct iovec) * iter->nr_segs); |
565 | } else { |
566 | req->flags |= REQ_F_NEED_CLEANUP; |
567 | } |
568 | } |
569 | |
570 | static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, |
571 | struct io_rw_state *s, bool force) |
572 | { |
573 | if (!force && !io_cold_defs[req->opcode].prep_async) |
574 | return 0; |
575 | /* opcode type doesn't need async data */ |
576 | if (!io_cold_defs[req->opcode].async_size) |
577 | return 0; |
578 | if (!req_has_async_data(req)) { |
579 | struct io_async_rw *iorw; |
580 | |
581 | if (io_alloc_async_data(req)) { |
582 | kfree(objp: iovec); |
583 | return -ENOMEM; |
584 | } |
585 | |
586 | io_req_map_rw(req, iovec, fast_iov: s->fast_iov, iter: &s->iter); |
587 | iorw = req->async_data; |
588 | /* we've copied and mapped the iter, ensure state is saved */ |
589 | iov_iter_save_state(iter: &iorw->s.iter, state: &iorw->s.iter_state); |
590 | } |
591 | return 0; |
592 | } |
593 | |
594 | static inline int io_rw_prep_async(struct io_kiocb *req, int rw) |
595 | { |
596 | struct io_async_rw *iorw = req->async_data; |
597 | struct iovec *iov; |
598 | int ret; |
599 | |
600 | iorw->bytes_done = 0; |
601 | iorw->free_iovec = NULL; |
602 | |
603 | /* submission path, ->uring_lock should already be taken */ |
604 | ret = io_import_iovec(rw, req, iovec: &iov, s: &iorw->s, issue_flags: 0); |
605 | if (unlikely(ret < 0)) |
606 | return ret; |
607 | |
608 | if (iov) { |
609 | iorw->free_iovec = iov; |
610 | req->flags |= REQ_F_NEED_CLEANUP; |
611 | } |
612 | |
613 | return 0; |
614 | } |
615 | |
616 | int io_readv_prep_async(struct io_kiocb *req) |
617 | { |
618 | return io_rw_prep_async(req, ITER_DEST); |
619 | } |
620 | |
621 | int io_writev_prep_async(struct io_kiocb *req) |
622 | { |
623 | return io_rw_prep_async(req, ITER_SOURCE); |
624 | } |
625 | |
626 | /* |
627 | * This is our waitqueue callback handler, registered through __folio_lock_async() |
628 | * when we initially tried to do the IO with the iocb armed our waitqueue. |
629 | * This gets called when the page is unlocked, and we generally expect that to |
630 | * happen when the page IO is completed and the page is now uptodate. This will |
631 | * queue a task_work based retry of the operation, attempting to copy the data |
632 | * again. If the latter fails because the page was NOT uptodate, then we will |
633 | * do a thread based blocking retry of the operation. That's the unexpected |
634 | * slow path. |
635 | */ |
636 | static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, |
637 | int sync, void *arg) |
638 | { |
639 | struct wait_page_queue *wpq; |
640 | struct io_kiocb *req = wait->private; |
641 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
642 | struct wait_page_key *key = arg; |
643 | |
644 | wpq = container_of(wait, struct wait_page_queue, wait); |
645 | |
646 | if (!wake_page_match(wait_page: wpq, key)) |
647 | return 0; |
648 | |
649 | rw->kiocb.ki_flags &= ~IOCB_WAITQ; |
650 | list_del_init(entry: &wait->entry); |
651 | io_req_task_queue(req); |
652 | return 1; |
653 | } |
654 | |
655 | /* |
656 | * This controls whether a given IO request should be armed for async page |
657 | * based retry. If we return false here, the request is handed to the async |
658 | * worker threads for retry. If we're doing buffered reads on a regular file, |
659 | * we prepare a private wait_page_queue entry and retry the operation. This |
660 | * will either succeed because the page is now uptodate and unlocked, or it |
661 | * will register a callback when the page is unlocked at IO completion. Through |
662 | * that callback, io_uring uses task_work to setup a retry of the operation. |
663 | * That retry will attempt the buffered read again. The retry will generally |
664 | * succeed, or in rare cases where it fails, we then fall back to using the |
665 | * async worker threads for a blocking retry. |
666 | */ |
667 | static bool io_rw_should_retry(struct io_kiocb *req) |
668 | { |
669 | struct io_async_rw *io = req->async_data; |
670 | struct wait_page_queue *wait = &io->wpq; |
671 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
672 | struct kiocb *kiocb = &rw->kiocb; |
673 | |
674 | /* never retry for NOWAIT, we just complete with -EAGAIN */ |
675 | if (req->flags & REQ_F_NOWAIT) |
676 | return false; |
677 | |
678 | /* Only for buffered IO */ |
679 | if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI)) |
680 | return false; |
681 | |
682 | /* |
683 | * just use poll if we can, and don't attempt if the fs doesn't |
684 | * support callback based unlocks |
685 | */ |
686 | if (io_file_can_poll(req) || !(req->file->f_mode & FMODE_BUF_RASYNC)) |
687 | return false; |
688 | |
689 | wait->wait.func = io_async_buf_func; |
690 | wait->wait.private = req; |
691 | wait->wait.flags = 0; |
692 | INIT_LIST_HEAD(list: &wait->wait.entry); |
693 | kiocb->ki_flags |= IOCB_WAITQ; |
694 | kiocb->ki_flags &= ~IOCB_NOWAIT; |
695 | kiocb->ki_waitq = wait; |
696 | return true; |
697 | } |
698 | |
699 | static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter) |
700 | { |
701 | struct file *file = rw->kiocb.ki_filp; |
702 | |
703 | if (likely(file->f_op->read_iter)) |
704 | return call_read_iter(file, kio: &rw->kiocb, iter); |
705 | else if (file->f_op->read) |
706 | return loop_rw_iter(READ, rw, iter); |
707 | else |
708 | return -EINVAL; |
709 | } |
710 | |
711 | static bool need_complete_io(struct io_kiocb *req) |
712 | { |
713 | return req->flags & REQ_F_ISREG || |
714 | S_ISBLK(file_inode(req->file)->i_mode); |
715 | } |
716 | |
717 | static int io_rw_init_file(struct io_kiocb *req, fmode_t mode) |
718 | { |
719 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
720 | struct kiocb *kiocb = &rw->kiocb; |
721 | struct io_ring_ctx *ctx = req->ctx; |
722 | struct file *file = req->file; |
723 | int ret; |
724 | |
725 | if (unlikely(!(file->f_mode & mode))) |
726 | return -EBADF; |
727 | |
728 | if (!(req->flags & REQ_F_FIXED_FILE)) |
729 | req->flags |= io_file_get_flags(file); |
730 | |
731 | kiocb->ki_flags = file->f_iocb_flags; |
732 | ret = kiocb_set_rw_flags(ki: kiocb, flags: rw->flags); |
733 | if (unlikely(ret)) |
734 | return ret; |
735 | kiocb->ki_flags |= IOCB_ALLOC_CACHE; |
736 | |
737 | /* |
738 | * If the file is marked O_NONBLOCK, still allow retry for it if it |
739 | * supports async. Otherwise it's impossible to use O_NONBLOCK files |
740 | * reliably. If not, or it IOCB_NOWAIT is set, don't retry. |
741 | */ |
742 | if ((kiocb->ki_flags & IOCB_NOWAIT) || |
743 | ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req))) |
744 | req->flags |= REQ_F_NOWAIT; |
745 | |
746 | if (ctx->flags & IORING_SETUP_IOPOLL) { |
747 | if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll) |
748 | return -EOPNOTSUPP; |
749 | |
750 | kiocb->private = NULL; |
751 | kiocb->ki_flags |= IOCB_HIPRI; |
752 | kiocb->ki_complete = io_complete_rw_iopoll; |
753 | req->iopoll_completed = 0; |
754 | } else { |
755 | if (kiocb->ki_flags & IOCB_HIPRI) |
756 | return -EINVAL; |
757 | kiocb->ki_complete = io_complete_rw; |
758 | } |
759 | |
760 | return 0; |
761 | } |
762 | |
763 | static int __io_read(struct io_kiocb *req, unsigned int issue_flags) |
764 | { |
765 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
766 | struct io_rw_state __s, *s = &__s; |
767 | struct iovec *iovec; |
768 | struct kiocb *kiocb = &rw->kiocb; |
769 | bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; |
770 | struct io_async_rw *io; |
771 | ssize_t ret, ret2; |
772 | loff_t *ppos; |
773 | |
774 | if (!req_has_async_data(req)) { |
775 | ret = io_import_iovec(ITER_DEST, req, iovec: &iovec, s, issue_flags); |
776 | if (unlikely(ret < 0)) |
777 | return ret; |
778 | } else { |
779 | io = req->async_data; |
780 | s = &io->s; |
781 | |
782 | /* |
783 | * Safe and required to re-import if we're using provided |
784 | * buffers, as we dropped the selected one before retry. |
785 | */ |
786 | if (io_do_buffer_select(req)) { |
787 | ret = io_import_iovec(ITER_DEST, req, iovec: &iovec, s, issue_flags); |
788 | if (unlikely(ret < 0)) |
789 | return ret; |
790 | } |
791 | |
792 | /* |
793 | * We come here from an earlier attempt, restore our state to |
794 | * match in case it doesn't. It's cheap enough that we don't |
795 | * need to make this conditional. |
796 | */ |
797 | iov_iter_restore(i: &s->iter, state: &s->iter_state); |
798 | iovec = NULL; |
799 | } |
800 | ret = io_rw_init_file(req, FMODE_READ); |
801 | if (unlikely(ret)) { |
802 | kfree(objp: iovec); |
803 | return ret; |
804 | } |
805 | req->cqe.res = iov_iter_count(i: &s->iter); |
806 | |
807 | if (force_nonblock) { |
808 | /* If the file doesn't support async, just async punt */ |
809 | if (unlikely(!io_file_supports_nowait(req))) { |
810 | ret = io_setup_async_rw(req, iovec, s, force: true); |
811 | return ret ?: -EAGAIN; |
812 | } |
813 | kiocb->ki_flags |= IOCB_NOWAIT; |
814 | } else { |
815 | /* Ensure we clear previously set non-block flag */ |
816 | kiocb->ki_flags &= ~IOCB_NOWAIT; |
817 | } |
818 | |
819 | ppos = io_kiocb_update_pos(req); |
820 | |
821 | ret = rw_verify_area(READ, req->file, ppos, req->cqe.res); |
822 | if (unlikely(ret)) { |
823 | kfree(objp: iovec); |
824 | return ret; |
825 | } |
826 | |
827 | ret = io_iter_do_read(rw, iter: &s->iter); |
828 | |
829 | if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { |
830 | req->flags &= ~REQ_F_REISSUE; |
831 | /* |
832 | * If we can poll, just do that. For a vectored read, we'll |
833 | * need to copy state first. |
834 | */ |
835 | if (io_file_can_poll(req) && !io_issue_defs[req->opcode].vectored) |
836 | return -EAGAIN; |
837 | /* IOPOLL retry should happen for io-wq threads */ |
838 | if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) |
839 | goto done; |
840 | /* no retry on NONBLOCK nor RWF_NOWAIT */ |
841 | if (req->flags & REQ_F_NOWAIT) |
842 | goto done; |
843 | ret = 0; |
844 | } else if (ret == -EIOCBQUEUED) { |
845 | if (iovec) |
846 | kfree(objp: iovec); |
847 | return IOU_ISSUE_SKIP_COMPLETE; |
848 | } else if (ret == req->cqe.res || ret <= 0 || !force_nonblock || |
849 | (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) { |
850 | /* read all, failed, already did sync or don't want to retry */ |
851 | goto done; |
852 | } |
853 | |
854 | /* |
855 | * Don't depend on the iter state matching what was consumed, or being |
856 | * untouched in case of error. Restore it and we'll advance it |
857 | * manually if we need to. |
858 | */ |
859 | iov_iter_restore(i: &s->iter, state: &s->iter_state); |
860 | |
861 | ret2 = io_setup_async_rw(req, iovec, s, force: true); |
862 | iovec = NULL; |
863 | if (ret2) { |
864 | ret = ret > 0 ? ret : ret2; |
865 | goto done; |
866 | } |
867 | |
868 | io = req->async_data; |
869 | s = &io->s; |
870 | /* |
871 | * Now use our persistent iterator and state, if we aren't already. |
872 | * We've restored and mapped the iter to match. |
873 | */ |
874 | |
875 | do { |
876 | /* |
877 | * We end up here because of a partial read, either from |
878 | * above or inside this loop. Advance the iter by the bytes |
879 | * that were consumed. |
880 | */ |
881 | iov_iter_advance(i: &s->iter, bytes: ret); |
882 | if (!iov_iter_count(i: &s->iter)) |
883 | break; |
884 | io->bytes_done += ret; |
885 | iov_iter_save_state(iter: &s->iter, state: &s->iter_state); |
886 | |
887 | /* if we can retry, do so with the callbacks armed */ |
888 | if (!io_rw_should_retry(req)) { |
889 | kiocb->ki_flags &= ~IOCB_WAITQ; |
890 | return -EAGAIN; |
891 | } |
892 | |
893 | req->cqe.res = iov_iter_count(i: &s->iter); |
894 | /* |
895 | * Now retry read with the IOCB_WAITQ parts set in the iocb. If |
896 | * we get -EIOCBQUEUED, then we'll get a notification when the |
897 | * desired page gets unlocked. We can also get a partial read |
898 | * here, and if we do, then just retry at the new offset. |
899 | */ |
900 | ret = io_iter_do_read(rw, iter: &s->iter); |
901 | if (ret == -EIOCBQUEUED) |
902 | return IOU_ISSUE_SKIP_COMPLETE; |
903 | /* we got some bytes, but not all. retry. */ |
904 | kiocb->ki_flags &= ~IOCB_WAITQ; |
905 | iov_iter_restore(i: &s->iter, state: &s->iter_state); |
906 | } while (ret > 0); |
907 | done: |
908 | /* it's faster to check here then delegate to kfree */ |
909 | if (iovec) |
910 | kfree(objp: iovec); |
911 | return ret; |
912 | } |
913 | |
914 | int io_read(struct io_kiocb *req, unsigned int issue_flags) |
915 | { |
916 | int ret; |
917 | |
918 | ret = __io_read(req, issue_flags); |
919 | if (ret >= 0) |
920 | return kiocb_done(req, ret, issue_flags); |
921 | |
922 | return ret; |
923 | } |
924 | |
925 | int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags) |
926 | { |
927 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
928 | unsigned int cflags = 0; |
929 | int ret; |
930 | |
931 | /* |
932 | * Multishot MUST be used on a pollable file |
933 | */ |
934 | if (!io_file_can_poll(req)) |
935 | return -EBADFD; |
936 | |
937 | ret = __io_read(req, issue_flags); |
938 | |
939 | /* |
940 | * If the file doesn't support proper NOWAIT, then disable multishot |
941 | * and stay in single shot mode. |
942 | */ |
943 | if (!io_file_supports_nowait(req)) |
944 | req->flags &= ~REQ_F_APOLL_MULTISHOT; |
945 | |
946 | /* |
947 | * If we get -EAGAIN, recycle our buffer and just let normal poll |
948 | * handling arm it. |
949 | */ |
950 | if (ret == -EAGAIN) { |
951 | /* |
952 | * Reset rw->len to 0 again to avoid clamping future mshot |
953 | * reads, in case the buffer size varies. |
954 | */ |
955 | if (io_kbuf_recycle(req, issue_flags)) |
956 | rw->len = 0; |
957 | if (issue_flags & IO_URING_F_MULTISHOT) |
958 | return IOU_ISSUE_SKIP_COMPLETE; |
959 | return -EAGAIN; |
960 | } |
961 | |
962 | /* |
963 | * Any successful return value will keep the multishot read armed. |
964 | */ |
965 | if (ret > 0 && req->flags & REQ_F_APOLL_MULTISHOT) { |
966 | /* |
967 | * Put our buffer and post a CQE. If we fail to post a CQE, then |
968 | * jump to the termination path. This request is then done. |
969 | */ |
970 | cflags = io_put_kbuf(req, issue_flags); |
971 | rw->len = 0; /* similarly to above, reset len to 0 */ |
972 | |
973 | if (io_fill_cqe_req_aux(req, |
974 | defer: issue_flags & IO_URING_F_COMPLETE_DEFER, |
975 | res: ret, cflags: cflags | IORING_CQE_F_MORE)) { |
976 | if (issue_flags & IO_URING_F_MULTISHOT) { |
977 | /* |
978 | * Force retry, as we might have more data to |
979 | * be read and otherwise it won't get retried |
980 | * until (if ever) another poll is triggered. |
981 | */ |
982 | io_poll_multishot_retry(req); |
983 | return IOU_ISSUE_SKIP_COMPLETE; |
984 | } |
985 | return -EAGAIN; |
986 | } |
987 | } |
988 | |
989 | /* |
990 | * Either an error, or we've hit overflow posting the CQE. For any |
991 | * multishot request, hitting overflow will terminate it. |
992 | */ |
993 | io_req_set_res(req, res: ret, cflags); |
994 | if (issue_flags & IO_URING_F_MULTISHOT) |
995 | return IOU_STOP_MULTISHOT; |
996 | return IOU_OK; |
997 | } |
998 | |
999 | int io_write(struct io_kiocb *req, unsigned int issue_flags) |
1000 | { |
1001 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
1002 | struct io_rw_state __s, *s = &__s; |
1003 | struct iovec *iovec; |
1004 | struct kiocb *kiocb = &rw->kiocb; |
1005 | bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; |
1006 | ssize_t ret, ret2; |
1007 | loff_t *ppos; |
1008 | |
1009 | if (!req_has_async_data(req)) { |
1010 | ret = io_import_iovec(ITER_SOURCE, req, iovec: &iovec, s, issue_flags); |
1011 | if (unlikely(ret < 0)) |
1012 | return ret; |
1013 | } else { |
1014 | struct io_async_rw *io = req->async_data; |
1015 | |
1016 | s = &io->s; |
1017 | iov_iter_restore(i: &s->iter, state: &s->iter_state); |
1018 | iovec = NULL; |
1019 | } |
1020 | ret = io_rw_init_file(req, FMODE_WRITE); |
1021 | if (unlikely(ret)) { |
1022 | kfree(objp: iovec); |
1023 | return ret; |
1024 | } |
1025 | req->cqe.res = iov_iter_count(i: &s->iter); |
1026 | |
1027 | if (force_nonblock) { |
1028 | /* If the file doesn't support async, just async punt */ |
1029 | if (unlikely(!io_file_supports_nowait(req))) |
1030 | goto copy_iov; |
1031 | |
1032 | /* File path supports NOWAIT for non-direct_IO only for block devices. */ |
1033 | if (!(kiocb->ki_flags & IOCB_DIRECT) && |
1034 | !(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) && |
1035 | (req->flags & REQ_F_ISREG)) |
1036 | goto copy_iov; |
1037 | |
1038 | kiocb->ki_flags |= IOCB_NOWAIT; |
1039 | } else { |
1040 | /* Ensure we clear previously set non-block flag */ |
1041 | kiocb->ki_flags &= ~IOCB_NOWAIT; |
1042 | } |
1043 | |
1044 | ppos = io_kiocb_update_pos(req); |
1045 | |
1046 | ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res); |
1047 | if (unlikely(ret)) { |
1048 | kfree(objp: iovec); |
1049 | return ret; |
1050 | } |
1051 | |
1052 | if (req->flags & REQ_F_ISREG) |
1053 | kiocb_start_write(iocb: kiocb); |
1054 | kiocb->ki_flags |= IOCB_WRITE; |
1055 | |
1056 | if (likely(req->file->f_op->write_iter)) |
1057 | ret2 = call_write_iter(file: req->file, kio: kiocb, iter: &s->iter); |
1058 | else if (req->file->f_op->write) |
1059 | ret2 = loop_rw_iter(WRITE, rw, iter: &s->iter); |
1060 | else |
1061 | ret2 = -EINVAL; |
1062 | |
1063 | if (req->flags & REQ_F_REISSUE) { |
1064 | req->flags &= ~REQ_F_REISSUE; |
1065 | ret2 = -EAGAIN; |
1066 | } |
1067 | |
1068 | /* |
1069 | * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just |
1070 | * retry them without IOCB_NOWAIT. |
1071 | */ |
1072 | if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) |
1073 | ret2 = -EAGAIN; |
1074 | /* no retry on NONBLOCK nor RWF_NOWAIT */ |
1075 | if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) |
1076 | goto done; |
1077 | if (!force_nonblock || ret2 != -EAGAIN) { |
1078 | /* IOPOLL retry should happen for io-wq threads */ |
1079 | if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL)) |
1080 | goto copy_iov; |
1081 | |
1082 | if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) { |
1083 | struct io_async_rw *io; |
1084 | |
1085 | trace_io_uring_short_write(ctx: req->ctx, fpos: kiocb->ki_pos - ret2, |
1086 | wanted: req->cqe.res, got: ret2); |
1087 | |
1088 | /* This is a partial write. The file pos has already been |
1089 | * updated, setup the async struct to complete the request |
1090 | * in the worker. Also update bytes_done to account for |
1091 | * the bytes already written. |
1092 | */ |
1093 | iov_iter_save_state(iter: &s->iter, state: &s->iter_state); |
1094 | ret = io_setup_async_rw(req, iovec, s, force: true); |
1095 | |
1096 | io = req->async_data; |
1097 | if (io) |
1098 | io->bytes_done += ret2; |
1099 | |
1100 | if (kiocb->ki_flags & IOCB_WRITE) |
1101 | io_req_end_write(req); |
1102 | return ret ? ret : -EAGAIN; |
1103 | } |
1104 | done: |
1105 | ret = kiocb_done(req, ret: ret2, issue_flags); |
1106 | } else { |
1107 | copy_iov: |
1108 | iov_iter_restore(i: &s->iter, state: &s->iter_state); |
1109 | ret = io_setup_async_rw(req, iovec, s, force: false); |
1110 | if (!ret) { |
1111 | if (kiocb->ki_flags & IOCB_WRITE) |
1112 | io_req_end_write(req); |
1113 | return -EAGAIN; |
1114 | } |
1115 | return ret; |
1116 | } |
1117 | /* it's reportedly faster than delegating the null check to kfree() */ |
1118 | if (iovec) |
1119 | kfree(objp: iovec); |
1120 | return ret; |
1121 | } |
1122 | |
1123 | void io_rw_fail(struct io_kiocb *req) |
1124 | { |
1125 | int res; |
1126 | |
1127 | res = io_fixup_rw_res(req, res: req->cqe.res); |
1128 | io_req_set_res(req, res, cflags: req->cqe.flags); |
1129 | } |
1130 | |
1131 | int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) |
1132 | { |
1133 | struct io_wq_work_node *pos, *start, *prev; |
1134 | unsigned int poll_flags = 0; |
1135 | DEFINE_IO_COMP_BATCH(iob); |
1136 | int nr_events = 0; |
1137 | |
1138 | /* |
1139 | * Only spin for completions if we don't have multiple devices hanging |
1140 | * off our complete list. |
1141 | */ |
1142 | if (ctx->poll_multi_queue || force_nonspin) |
1143 | poll_flags |= BLK_POLL_ONESHOT; |
1144 | |
1145 | wq_list_for_each(pos, start, &ctx->iopoll_list) { |
1146 | struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); |
1147 | struct file *file = req->file; |
1148 | int ret; |
1149 | |
1150 | /* |
1151 | * Move completed and retryable entries to our local lists. |
1152 | * If we find a request that requires polling, break out |
1153 | * and complete those lists first, if we have entries there. |
1154 | */ |
1155 | if (READ_ONCE(req->iopoll_completed)) |
1156 | break; |
1157 | |
1158 | if (req->opcode == IORING_OP_URING_CMD) { |
1159 | struct io_uring_cmd *ioucmd; |
1160 | |
1161 | ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); |
1162 | ret = file->f_op->uring_cmd_iopoll(ioucmd, &iob, |
1163 | poll_flags); |
1164 | } else { |
1165 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
1166 | |
1167 | ret = file->f_op->iopoll(&rw->kiocb, &iob, poll_flags); |
1168 | } |
1169 | if (unlikely(ret < 0)) |
1170 | return ret; |
1171 | else if (ret) |
1172 | poll_flags |= BLK_POLL_ONESHOT; |
1173 | |
1174 | /* iopoll may have completed current req */ |
1175 | if (!rq_list_empty(iob.req_list) || |
1176 | READ_ONCE(req->iopoll_completed)) |
1177 | break; |
1178 | } |
1179 | |
1180 | if (!rq_list_empty(iob.req_list)) |
1181 | iob.complete(&iob); |
1182 | else if (!pos) |
1183 | return 0; |
1184 | |
1185 | prev = start; |
1186 | wq_list_for_each_resume(pos, prev) { |
1187 | struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); |
1188 | |
1189 | /* order with io_complete_rw_iopoll(), e.g. ->result updates */ |
1190 | if (!smp_load_acquire(&req->iopoll_completed)) |
1191 | break; |
1192 | nr_events++; |
1193 | req->cqe.flags = io_put_kbuf(req, issue_flags: 0); |
1194 | } |
1195 | if (unlikely(!nr_events)) |
1196 | return 0; |
1197 | |
1198 | pos = start ? start->next : ctx->iopoll_list.first; |
1199 | wq_list_cut(list: &ctx->iopoll_list, last: prev, prev: start); |
1200 | |
1201 | if (WARN_ON_ONCE(!wq_list_empty(&ctx->submit_state.compl_reqs))) |
1202 | return 0; |
1203 | ctx->submit_state.compl_reqs.first = pos; |
1204 | __io_submit_flush_completions(ctx); |
1205 | return nr_events; |
1206 | } |
1207 | |