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f3b44f92 JA |
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> | |
b66509b8 | 13 | #include <linux/io_uring/cmd.h> |
3fb1764c | 14 | #include <linux/indirect_call_wrapper.h> |
f3b44f92 JA |
15 | |
16 | #include <uapi/linux/io_uring.h> | |
17 | ||
f3b44f92 JA |
18 | #include "io_uring.h" |
19 | #include "opdef.h" | |
20 | #include "kbuf.h" | |
21 | #include "rsrc.h" | |
c79f52f0 | 22 | #include "poll.h" |
f3b44f92 JA |
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 | ||
4ab9d465 DY |
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(&iov, uiov, sizeof(*uiov))) | |
73 | return -EFAULT; | |
74 | rw->len = iov.iov_len; | |
75 | return 0; | |
76 | } | |
77 | ||
f3b44f92 JA |
78 | int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
79 | { | |
f2ccb5ae | 80 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
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 | ||
f3b44f92 JA |
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 | } | |
099ada2c | 98 | rw->kiocb.dio_complete = NULL; |
f3b44f92 JA |
99 | |
100 | rw->addr = READ_ONCE(sqe->addr); | |
101 | rw->len = READ_ONCE(sqe->len); | |
102 | rw->flags = READ_ONCE(sqe->rw_flags); | |
0e984ec8 JA |
103 | return 0; |
104 | } | |
105 | ||
106 | int io_prep_rwv(struct io_kiocb *req, const struct io_uring_sqe *sqe) | |
107 | { | |
108 | int ret; | |
4ab9d465 | 109 | |
0e984ec8 JA |
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 | |
4ab9d465 | 117 | */ |
0e984ec8 JA |
118 | if (req->flags & REQ_F_BUFFER_SELECT) |
119 | return io_iov_buffer_select_prep(req); | |
4ab9d465 | 120 | |
f3b44f92 JA |
121 | return 0; |
122 | } | |
123 | ||
f688944c JA |
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, 0); | |
139 | return 0; | |
140 | } | |
141 | ||
fc68fcda JA |
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 | { | |
49fbe994 | 148 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
fc68fcda JA |
149 | int ret; |
150 | ||
0df96fb7 JA |
151 | /* must be used with provided buffers */ |
152 | if (!(req->flags & REQ_F_BUFFER_SELECT)) | |
153 | return -EINVAL; | |
154 | ||
fc68fcda JA |
155 | ret = io_prep_rw(req, sqe); |
156 | if (unlikely(ret)) | |
157 | return ret; | |
158 | ||
49fbe994 DY |
159 | if (rw->addr || rw->len) |
160 | return -EINVAL; | |
161 | ||
fc68fcda JA |
162 | req->flags |= REQ_F_APOLL_MULTISHOT; |
163 | return 0; | |
164 | } | |
165 | ||
f3b44f92 JA |
166 | void io_readv_writev_cleanup(struct io_kiocb *req) |
167 | { | |
168 | struct io_async_rw *io = req->async_data; | |
169 | ||
170 | kfree(io->free_iovec); | |
171 | } | |
172 | ||
f3b44f92 JA |
173 | static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req) |
174 | { | |
f2ccb5ae | 175 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
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(&io->s.iter, &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(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(&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(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 | ||
a370167f | 243 | static void io_req_end_write(struct io_kiocb *req) |
f3b44f92 | 244 | { |
f3b44f92 | 245 | if (req->flags & REQ_F_ISREG) { |
e484fd73 | 246 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 | 247 | |
e484fd73 | 248 | kiocb_end_write(&rw->kiocb); |
f3b44f92 JA |
249 | } |
250 | } | |
251 | ||
2ec33a6c JA |
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 | ||
2ec33a6c | 260 | if (rw->kiocb.ki_flags & IOCB_WRITE) { |
a370167f | 261 | io_req_end_write(req); |
2ec33a6c JA |
262 | fsnotify_modify(req->file); |
263 | } else { | |
264 | fsnotify_access(req->file); | |
265 | } | |
266 | } | |
267 | ||
f3b44f92 JA |
268 | static bool __io_complete_rw_common(struct io_kiocb *req, long res) |
269 | { | |
f3b44f92 JA |
270 | if (unlikely(res != req->cqe.res)) { |
271 | if ((res == -EAGAIN || res == -EOPNOTSUPP) && | |
272 | io_rw_should_reissue(req)) { | |
2ec33a6c JA |
273 | /* |
274 | * Reissue will start accounting again, finish the | |
275 | * current cycle. | |
276 | */ | |
277 | io_req_io_end(req); | |
186daf23 | 278 | req->flags |= REQ_F_REISSUE | REQ_F_BL_NO_RECYCLE; |
f3b44f92 JA |
279 | return true; |
280 | } | |
281 | req_set_fail(req); | |
282 | req->cqe.res = res; | |
283 | } | |
284 | return false; | |
285 | } | |
286 | ||
62bb0647 | 287 | static inline int io_fixup_rw_res(struct io_kiocb *req, long res) |
4d9cb92c PB |
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 | ||
c92fcfc2 | 301 | void io_req_rw_complete(struct io_kiocb *req, struct io_tw_state *ts) |
b000145e | 302 | { |
099ada2c JA |
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, io_fixup_rw_res(req, res), 0); | |
310 | } | |
311 | ||
2ec33a6c | 312 | io_req_io_end(req); |
3671163b PB |
313 | |
314 | if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) { | |
a282967c | 315 | unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED; |
3671163b PB |
316 | |
317 | req->cqe.flags |= io_put_kbuf(req, issue_flags); | |
318 | } | |
a282967c | 319 | io_req_task_complete(req, ts); |
b000145e JA |
320 | } |
321 | ||
f3b44f92 JA |
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 | ||
099ada2c JA |
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, io_fixup_rw_res(req, res), 0); | |
331 | } | |
b000145e | 332 | req->io_task_work.func = io_req_rw_complete; |
8751d154 | 333 | __io_req_task_work_add(req, IOU_F_TWQ_LAZY_WAKE); |
f3b44f92 JA |
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) | |
a370167f | 342 | io_req_end_write(req); |
f3b44f92 JA |
343 | if (unlikely(res != req->cqe.res)) { |
344 | if (res == -EAGAIN && io_rw_should_reissue(req)) { | |
186daf23 | 345 | req->flags |= REQ_F_REISSUE | REQ_F_BL_NO_RECYCLE; |
f3b44f92 JA |
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 | ||
fe80eb15 JA |
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 | ||
df9830d8 | 382 | static int kiocb_done(struct io_kiocb *req, ssize_t ret, |
f3b44f92 JA |
383 | unsigned int issue_flags) |
384 | { | |
f2ccb5ae | 385 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
4d9cb92c | 386 | unsigned final_ret = io_fixup_rw_res(req, ret); |
f3b44f92 | 387 | |
1939316b | 388 | if (ret >= 0 && req->flags & REQ_F_CUR_POS) |
f3b44f92 | 389 | req->file->f_pos = rw->kiocb.ki_pos; |
df9830d8 PB |
390 | if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) { |
391 | if (!__io_complete_rw_common(req, ret)) { | |
2ec33a6c JA |
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); | |
4d9cb92c | 397 | io_req_set_res(req, final_ret, |
df9830d8 PB |
398 | io_put_kbuf(req, issue_flags)); |
399 | return IOU_OK; | |
400 | } | |
401 | } else { | |
f3b44f92 | 402 | io_rw_done(&rw->kiocb, ret); |
df9830d8 | 403 | } |
f3b44f92 JA |
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 | |
4d9cb92c | 410 | io_req_task_queue_fail(req, final_ret); |
f3b44f92 | 411 | } |
df9830d8 | 412 | return IOU_ISSUE_SKIP_COMPLETE; |
f3b44f92 JA |
413 | } |
414 | ||
f3b44f92 JA |
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 | { | |
f2ccb5ae | 419 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
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) { | |
f337a84d | 428 | ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len); |
f3b44f92 JA |
429 | if (ret) |
430 | return ERR_PTR(ret); | |
431 | return NULL; | |
432 | } | |
433 | ||
434 | buf = u64_to_user_ptr(rw->addr); | |
435 | sqe_len = rw->len; | |
436 | ||
d2d778fb | 437 | if (!io_issue_defs[opcode].vectored || req->flags & REQ_F_BUFFER_SELECT) { |
f3b44f92 JA |
438 | if (io_do_buffer_select(req)) { |
439 | buf = io_buffer_select(req, &sqe_len, issue_flags); | |
440 | if (!buf) | |
441 | return ERR_PTR(-ENOBUFS); | |
442 | rw->addr = (unsigned long) buf; | |
443 | rw->len = sqe_len; | |
444 | } | |
445 | ||
1e23db45 | 446 | ret = import_ubuf(ddir, buf, sqe_len, iter); |
f3b44f92 JA |
447 | if (ret) |
448 | return ERR_PTR(ret); | |
449 | return NULL; | |
450 | } | |
451 | ||
452 | iovec = s->fast_iov; | |
f3b44f92 JA |
453 | ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter, |
454 | req->ctx->compat); | |
455 | if (unlikely(ret < 0)) | |
456 | return ERR_PTR(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(rw, req, s, issue_flags); | |
81594e7e | 465 | if (IS_ERR(*iovec)) |
f3b44f92 JA |
466 | return PTR_ERR(*iovec); |
467 | ||
468 | iov_iter_save_state(&s->iter, &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(iter)) { | |
95e49cf8 JA |
502 | void __user *addr; |
503 | size_t len; | |
f3b44f92 JA |
504 | ssize_t nr; |
505 | ||
1e23db45 | 506 | if (iter_is_ubuf(iter)) { |
95e49cf8 JA |
507 | addr = iter->ubuf + iter->iov_offset; |
508 | len = iov_iter_count(iter); | |
1e23db45 | 509 | } else if (!iov_iter_is_bvec(iter)) { |
95e49cf8 JA |
510 | addr = iter_iov_addr(iter); |
511 | len = iter_iov_len(iter); | |
f3b44f92 | 512 | } else { |
95e49cf8 JA |
513 | addr = u64_to_user_ptr(rw->addr); |
514 | len = rw->len; | |
f3b44f92 JA |
515 | } |
516 | ||
95e49cf8 JA |
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); | |
f3b44f92 JA |
521 | |
522 | if (nr < 0) { | |
523 | if (!ret) | |
524 | ret = nr; | |
525 | break; | |
526 | } | |
527 | ret += nr; | |
528 | if (!iov_iter_is_bvec(iter)) { | |
529 | iov_iter_advance(iter, nr); | |
530 | } else { | |
531 | rw->addr += nr; | |
532 | rw->len -= nr; | |
533 | if (!rw->len) | |
534 | break; | |
535 | } | |
95e49cf8 | 536 | if (nr != len) |
f3b44f92 JA |
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 */ | |
1e23db45 | 552 | if (iov_iter_is_bvec(iter) || iter_is_ubuf(iter)) |
f3b44f92 JA |
553 | return; |
554 | if (!iovec) { | |
555 | unsigned iov_off = 0; | |
556 | ||
de4f5fed JA |
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; | |
f3b44f92 JA |
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 | { | |
f30bd4d0 | 573 | if (!force && !io_cold_defs[req->opcode].prep_async) |
f3b44f92 | 574 | return 0; |
0df96fb7 JA |
575 | /* opcode type doesn't need async data */ |
576 | if (!io_cold_defs[req->opcode].async_size) | |
577 | return 0; | |
f3b44f92 JA |
578 | if (!req_has_async_data(req)) { |
579 | struct io_async_rw *iorw; | |
580 | ||
581 | if (io_alloc_async_data(req)) { | |
582 | kfree(iovec); | |
583 | return -ENOMEM; | |
584 | } | |
585 | ||
586 | io_req_map_rw(req, iovec, s->fast_iov, &s->iter); | |
587 | iorw = req->async_data; | |
588 | /* we've copied and mapped the iter, ensure state is saved */ | |
589 | iov_iter_save_state(&iorw->s.iter, &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 | ||
0a535edd JA |
600 | iorw->bytes_done = 0; |
601 | iorw->free_iovec = NULL; | |
602 | ||
f3b44f92 JA |
603 | /* submission path, ->uring_lock should already be taken */ |
604 | ret = io_import_iovec(rw, req, &iov, &iorw->s, 0); | |
605 | if (unlikely(ret < 0)) | |
606 | return ret; | |
607 | ||
0a535edd JA |
608 | if (iov) { |
609 | iorw->free_iovec = iov; | |
f3b44f92 | 610 | req->flags |= REQ_F_NEED_CLEANUP; |
0a535edd JA |
611 | } |
612 | ||
f3b44f92 JA |
613 | return 0; |
614 | } | |
615 | ||
616 | int io_readv_prep_async(struct io_kiocb *req) | |
617 | { | |
de4eda9d | 618 | return io_rw_prep_async(req, ITER_DEST); |
f3b44f92 JA |
619 | } |
620 | ||
621 | int io_writev_prep_async(struct io_kiocb *req) | |
622 | { | |
de4eda9d | 623 | return io_rw_prep_async(req, ITER_SOURCE); |
f3b44f92 JA |
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; | |
f2ccb5ae | 641 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
642 | struct wait_page_key *key = arg; |
643 | ||
644 | wpq = container_of(wait, struct wait_page_queue, wait); | |
645 | ||
646 | if (!wake_page_match(wpq, key)) | |
647 | return 0; | |
648 | ||
649 | rw->kiocb.ki_flags &= ~IOCB_WAITQ; | |
650 | list_del_init(&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; | |
f2ccb5ae | 671 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
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 | */ | |
95041b93 | 686 | if (io_file_can_poll(req) || !(req->file->f_mode & FMODE_BUF_RASYNC)) |
f3b44f92 JA |
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(&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, &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 | ||
4e17aaab | 711 | static bool need_complete_io(struct io_kiocb *req) |
f3b44f92 JA |
712 | { |
713 | return req->flags & REQ_F_ISREG || | |
714 | S_ISBLK(file_inode(req->file)->i_mode); | |
715 | } | |
716 | ||
f3b44f92 JA |
717 | static int io_rw_init_file(struct io_kiocb *req, fmode_t mode) |
718 | { | |
f2ccb5ae | 719 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
720 | struct kiocb *kiocb = &rw->kiocb; |
721 | struct io_ring_ctx *ctx = req->ctx; | |
722 | struct file *file = req->file; | |
723 | int ret; | |
724 | ||
949249e2 | 725 | if (unlikely(!(file->f_mode & mode))) |
f3b44f92 JA |
726 | return -EBADF; |
727 | ||
3beed235 | 728 | if (!(req->flags & REQ_F_FIXED_FILE)) |
8487f083 | 729 | req->flags |= io_file_get_flags(file); |
f3b44f92 | 730 | |
5264406c | 731 | kiocb->ki_flags = file->f_iocb_flags; |
f3b44f92 JA |
732 | ret = kiocb_set_rw_flags(kiocb, rw->flags); |
733 | if (unlikely(ret)) | |
734 | return ret; | |
12e4e8c7 | 735 | kiocb->ki_flags |= IOCB_ALLOC_CACHE; |
f3b44f92 JA |
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; | |
12e4e8c7 | 751 | kiocb->ki_flags |= IOCB_HIPRI; |
f3b44f92 JA |
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 | ||
a08d195b | 763 | static int __io_read(struct io_kiocb *req, unsigned int issue_flags) |
f3b44f92 | 764 | { |
f2ccb5ae | 765 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
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)) { | |
de4eda9d | 775 | ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags); |
f3b44f92 JA |
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)) { | |
de4eda9d | 787 | ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags); |
f3b44f92 JA |
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(&s->iter, &s->iter_state); | |
798 | iovec = NULL; | |
799 | } | |
800 | ret = io_rw_init_file(req, FMODE_READ); | |
801 | if (unlikely(ret)) { | |
802 | kfree(iovec); | |
803 | return ret; | |
804 | } | |
805 | req->cqe.res = iov_iter_count(&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, 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(iovec); | |
824 | return ret; | |
825 | } | |
826 | ||
827 | ret = io_iter_do_read(rw, &s->iter); | |
828 | ||
829 | if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { | |
830 | req->flags &= ~REQ_F_REISSUE; | |
d2d778fb JA |
831 | /* |
832 | * If we can poll, just do that. For a vectored read, we'll | |
833 | * need to copy state first. | |
834 | */ | |
95041b93 | 835 | if (io_file_can_poll(req) && !io_issue_defs[req->opcode].vectored) |
f3b44f92 JA |
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) { | |
df9830d8 PB |
845 | if (iovec) |
846 | kfree(iovec); | |
847 | return IOU_ISSUE_SKIP_COMPLETE; | |
f3b44f92 | 848 | } else if (ret == req->cqe.res || ret <= 0 || !force_nonblock || |
4e17aaab | 849 | (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) { |
f3b44f92 JA |
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(&s->iter, &s->iter_state); | |
860 | ||
861 | ret2 = io_setup_async_rw(req, iovec, s, true); | |
f3b44f92 | 862 | iovec = NULL; |
c278d9f8 PB |
863 | if (ret2) { |
864 | ret = ret > 0 ? ret : ret2; | |
865 | goto done; | |
866 | } | |
867 | ||
f3b44f92 JA |
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(&s->iter, ret); | |
882 | if (!iov_iter_count(&s->iter)) | |
883 | break; | |
884 | io->bytes_done += ret; | |
885 | iov_iter_save_state(&s->iter, &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 | ||
bf68b5b3 | 893 | req->cqe.res = iov_iter_count(&s->iter); |
f3b44f92 JA |
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, &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(&s->iter, &s->iter_state); | |
906 | } while (ret > 0); | |
907 | done: | |
f3b44f92 JA |
908 | /* it's faster to check here then delegate to kfree */ |
909 | if (iovec) | |
910 | kfree(iovec); | |
a08d195b JA |
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; | |
f3b44f92 JA |
923 | } |
924 | ||
fc68fcda JA |
925 | int io_read_mshot(struct io_kiocb *req, unsigned int issue_flags) |
926 | { | |
e5375929 | 927 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
fc68fcda JA |
928 | unsigned int cflags = 0; |
929 | int ret; | |
930 | ||
931 | /* | |
932 | * Multishot MUST be used on a pollable file | |
933 | */ | |
95041b93 | 934 | if (!io_file_can_poll(req)) |
fc68fcda JA |
935 | return -EBADFD; |
936 | ||
937 | ret = __io_read(req, issue_flags); | |
938 | ||
939 | /* | |
940 | * If we get -EAGAIN, recycle our buffer and just let normal poll | |
941 | * handling arm it. | |
942 | */ | |
943 | if (ret == -EAGAIN) { | |
e5375929 DY |
944 | /* |
945 | * Reset rw->len to 0 again to avoid clamping future mshot | |
946 | * reads, in case the buffer size varies. | |
947 | */ | |
948 | if (io_kbuf_recycle(req, issue_flags)) | |
949 | rw->len = 0; | |
fc68fcda JA |
950 | return -EAGAIN; |
951 | } | |
952 | ||
953 | /* | |
954 | * Any successful return value will keep the multishot read armed. | |
955 | */ | |
956 | if (ret > 0) { | |
957 | /* | |
958 | * Put our buffer and post a CQE. If we fail to post a CQE, then | |
959 | * jump to the termination path. This request is then done. | |
960 | */ | |
961 | cflags = io_put_kbuf(req, issue_flags); | |
e5375929 | 962 | rw->len = 0; /* similarly to above, reset len to 0 */ |
fc68fcda JA |
963 | |
964 | if (io_fill_cqe_req_aux(req, | |
965 | issue_flags & IO_URING_F_COMPLETE_DEFER, | |
966 | ret, cflags | IORING_CQE_F_MORE)) { | |
c79f52f0 JA |
967 | if (issue_flags & IO_URING_F_MULTISHOT) { |
968 | /* | |
969 | * Force retry, as we might have more data to | |
970 | * be read and otherwise it won't get retried | |
971 | * until (if ever) another poll is triggered. | |
972 | */ | |
973 | io_poll_multishot_retry(req); | |
fc68fcda | 974 | return IOU_ISSUE_SKIP_COMPLETE; |
c79f52f0 | 975 | } |
fc68fcda JA |
976 | return -EAGAIN; |
977 | } | |
978 | } | |
979 | ||
980 | /* | |
981 | * Either an error, or we've hit overflow posting the CQE. For any | |
982 | * multishot request, hitting overflow will terminate it. | |
983 | */ | |
984 | io_req_set_res(req, ret, cflags); | |
985 | if (issue_flags & IO_URING_F_MULTISHOT) | |
986 | return IOU_STOP_MULTISHOT; | |
987 | return IOU_OK; | |
f3b44f92 JA |
988 | } |
989 | ||
990 | int io_write(struct io_kiocb *req, unsigned int issue_flags) | |
991 | { | |
f2ccb5ae | 992 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
f3b44f92 JA |
993 | struct io_rw_state __s, *s = &__s; |
994 | struct iovec *iovec; | |
995 | struct kiocb *kiocb = &rw->kiocb; | |
996 | bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; | |
997 | ssize_t ret, ret2; | |
998 | loff_t *ppos; | |
999 | ||
1000 | if (!req_has_async_data(req)) { | |
de4eda9d | 1001 | ret = io_import_iovec(ITER_SOURCE, req, &iovec, s, issue_flags); |
f3b44f92 JA |
1002 | if (unlikely(ret < 0)) |
1003 | return ret; | |
1004 | } else { | |
1005 | struct io_async_rw *io = req->async_data; | |
1006 | ||
1007 | s = &io->s; | |
1008 | iov_iter_restore(&s->iter, &s->iter_state); | |
1009 | iovec = NULL; | |
1010 | } | |
1011 | ret = io_rw_init_file(req, FMODE_WRITE); | |
1012 | if (unlikely(ret)) { | |
1013 | kfree(iovec); | |
1014 | return ret; | |
1015 | } | |
1016 | req->cqe.res = iov_iter_count(&s->iter); | |
1017 | ||
1018 | if (force_nonblock) { | |
1019 | /* If the file doesn't support async, just async punt */ | |
1020 | if (unlikely(!io_file_supports_nowait(req))) | |
1021 | goto copy_iov; | |
1022 | ||
4e17aaab SR |
1023 | /* File path supports NOWAIT for non-direct_IO only for block devices. */ |
1024 | if (!(kiocb->ki_flags & IOCB_DIRECT) && | |
1025 | !(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) && | |
1026 | (req->flags & REQ_F_ISREG)) | |
f3b44f92 JA |
1027 | goto copy_iov; |
1028 | ||
1029 | kiocb->ki_flags |= IOCB_NOWAIT; | |
1030 | } else { | |
1031 | /* Ensure we clear previously set non-block flag */ | |
1032 | kiocb->ki_flags &= ~IOCB_NOWAIT; | |
1033 | } | |
1034 | ||
1035 | ppos = io_kiocb_update_pos(req); | |
1036 | ||
1037 | ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res); | |
df9830d8 PB |
1038 | if (unlikely(ret)) { |
1039 | kfree(iovec); | |
1040 | return ret; | |
1041 | } | |
f3b44f92 | 1042 | |
e484fd73 AG |
1043 | if (req->flags & REQ_F_ISREG) |
1044 | kiocb_start_write(kiocb); | |
f3b44f92 JA |
1045 | kiocb->ki_flags |= IOCB_WRITE; |
1046 | ||
1047 | if (likely(req->file->f_op->write_iter)) | |
1048 | ret2 = call_write_iter(req->file, kiocb, &s->iter); | |
1049 | else if (req->file->f_op->write) | |
1050 | ret2 = loop_rw_iter(WRITE, rw, &s->iter); | |
1051 | else | |
1052 | ret2 = -EINVAL; | |
1053 | ||
1054 | if (req->flags & REQ_F_REISSUE) { | |
1055 | req->flags &= ~REQ_F_REISSUE; | |
1056 | ret2 = -EAGAIN; | |
1057 | } | |
1058 | ||
1059 | /* | |
1060 | * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just | |
1061 | * retry them without IOCB_NOWAIT. | |
1062 | */ | |
1063 | if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) | |
1064 | ret2 = -EAGAIN; | |
1065 | /* no retry on NONBLOCK nor RWF_NOWAIT */ | |
1066 | if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) | |
1067 | goto done; | |
1068 | if (!force_nonblock || ret2 != -EAGAIN) { | |
1069 | /* IOPOLL retry should happen for io-wq threads */ | |
1070 | if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL)) | |
1071 | goto copy_iov; | |
4e17aaab SR |
1072 | |
1073 | if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) { | |
c86416c6 | 1074 | struct io_async_rw *io; |
4e17aaab | 1075 | |
1c849b48 SR |
1076 | trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2, |
1077 | req->cqe.res, ret2); | |
1078 | ||
4e17aaab SR |
1079 | /* This is a partial write. The file pos has already been |
1080 | * updated, setup the async struct to complete the request | |
1081 | * in the worker. Also update bytes_done to account for | |
1082 | * the bytes already written. | |
1083 | */ | |
1084 | iov_iter_save_state(&s->iter, &s->iter_state); | |
1085 | ret = io_setup_async_rw(req, iovec, s, true); | |
1086 | ||
c86416c6 SR |
1087 | io = req->async_data; |
1088 | if (io) | |
1089 | io->bytes_done += ret2; | |
4e17aaab | 1090 | |
e053aaf4 | 1091 | if (kiocb->ki_flags & IOCB_WRITE) |
a370167f | 1092 | io_req_end_write(req); |
4e17aaab SR |
1093 | return ret ? ret : -EAGAIN; |
1094 | } | |
f3b44f92 | 1095 | done: |
df9830d8 | 1096 | ret = kiocb_done(req, ret2, issue_flags); |
f3b44f92 JA |
1097 | } else { |
1098 | copy_iov: | |
1099 | iov_iter_restore(&s->iter, &s->iter_state); | |
1100 | ret = io_setup_async_rw(req, iovec, s, false); | |
e053aaf4 JA |
1101 | if (!ret) { |
1102 | if (kiocb->ki_flags & IOCB_WRITE) | |
a370167f | 1103 | io_req_end_write(req); |
e053aaf4 JA |
1104 | return -EAGAIN; |
1105 | } | |
1106 | return ret; | |
f3b44f92 | 1107 | } |
f3b44f92 JA |
1108 | /* it's reportedly faster than delegating the null check to kfree() */ |
1109 | if (iovec) | |
1110 | kfree(iovec); | |
1111 | return ret; | |
1112 | } | |
1113 | ||
47b4c686 PB |
1114 | void io_rw_fail(struct io_kiocb *req) |
1115 | { | |
1116 | int res; | |
1117 | ||
1118 | res = io_fixup_rw_res(req, req->cqe.res); | |
1119 | io_req_set_res(req, res, req->cqe.flags); | |
1120 | } | |
1121 | ||
f3b44f92 JA |
1122 | int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) |
1123 | { | |
1124 | struct io_wq_work_node *pos, *start, *prev; | |
54bdd67d | 1125 | unsigned int poll_flags = 0; |
f3b44f92 JA |
1126 | DEFINE_IO_COMP_BATCH(iob); |
1127 | int nr_events = 0; | |
1128 | ||
1129 | /* | |
1130 | * Only spin for completions if we don't have multiple devices hanging | |
1131 | * off our complete list. | |
1132 | */ | |
1133 | if (ctx->poll_multi_queue || force_nonspin) | |
1134 | poll_flags |= BLK_POLL_ONESHOT; | |
1135 | ||
1136 | wq_list_for_each(pos, start, &ctx->iopoll_list) { | |
1137 | struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); | |
a1119fb0 | 1138 | struct file *file = req->file; |
f3b44f92 JA |
1139 | int ret; |
1140 | ||
1141 | /* | |
1142 | * Move completed and retryable entries to our local lists. | |
1143 | * If we find a request that requires polling, break out | |
1144 | * and complete those lists first, if we have entries there. | |
1145 | */ | |
1146 | if (READ_ONCE(req->iopoll_completed)) | |
1147 | break; | |
1148 | ||
5756a3a7 | 1149 | if (req->opcode == IORING_OP_URING_CMD) { |
a1119fb0 | 1150 | struct io_uring_cmd *ioucmd; |
5756a3a7 | 1151 | |
a1119fb0 | 1152 | ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); |
de97fcb3 JA |
1153 | ret = file->f_op->uring_cmd_iopoll(ioucmd, &iob, |
1154 | poll_flags); | |
a1119fb0 JA |
1155 | } else { |
1156 | struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); | |
1157 | ||
1158 | ret = file->f_op->iopoll(&rw->kiocb, &iob, poll_flags); | |
1159 | } | |
f3b44f92 JA |
1160 | if (unlikely(ret < 0)) |
1161 | return ret; | |
1162 | else if (ret) | |
1163 | poll_flags |= BLK_POLL_ONESHOT; | |
1164 | ||
1165 | /* iopoll may have completed current req */ | |
1166 | if (!rq_list_empty(iob.req_list) || | |
1167 | READ_ONCE(req->iopoll_completed)) | |
1168 | break; | |
1169 | } | |
1170 | ||
1171 | if (!rq_list_empty(iob.req_list)) | |
1172 | iob.complete(&iob); | |
1173 | else if (!pos) | |
1174 | return 0; | |
1175 | ||
1176 | prev = start; | |
1177 | wq_list_for_each_resume(pos, prev) { | |
1178 | struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); | |
1179 | ||
1180 | /* order with io_complete_rw_iopoll(), e.g. ->result updates */ | |
1181 | if (!smp_load_acquire(&req->iopoll_completed)) | |
1182 | break; | |
1183 | nr_events++; | |
f3b44f92 | 1184 | req->cqe.flags = io_put_kbuf(req, 0); |
f3b44f92 | 1185 | } |
f3b44f92 JA |
1186 | if (unlikely(!nr_events)) |
1187 | return 0; | |
1188 | ||
f3b44f92 JA |
1189 | pos = start ? start->next : ctx->iopoll_list.first; |
1190 | wq_list_cut(&ctx->iopoll_list, prev, start); | |
ec26c225 PB |
1191 | |
1192 | if (WARN_ON_ONCE(!wq_list_empty(&ctx->submit_state.compl_reqs))) | |
1193 | return 0; | |
1194 | ctx->submit_state.compl_reqs.first = pos; | |
1195 | __io_submit_flush_completions(ctx); | |
f3b44f92 JA |
1196 | return nr_events; |
1197 | } |