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