xref: /linux/io_uring/io_uring.h (revision 61a11cf4812726aceaee17c96432e1c08f6ed6cb) 
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef IOU_CORE_H
3 #define IOU_CORE_H
4 
5 #include <linux/errno.h>
6 #include <linux/lockdep.h>
7 #include <linux/resume_user_mode.h>
8 #include <linux/poll.h>
9 #include <linux/io_uring_types.h>
10 #include <uapi/linux/eventpoll.h>
11 #include "alloc_cache.h"
12 #include "io-wq.h"
13 #include "slist.h"
14 #include "tw.h"
15 #include "opdef.h"
16 
17 #ifndef CREATE_TRACE_POINTS
18 #include <trace/events/io_uring.h>
19 #endif
20 
21 struct io_rings_layout {
22 	/* size of CQ + headers + SQ offset array */
23 	size_t rings_size;
24 	size_t sq_size;
25 
26 	size_t sq_array_offset;
27 };
28 
29 struct io_ctx_config {
30 	struct io_uring_params p;
31 	struct io_rings_layout layout;
32 	struct io_uring_params __user *uptr;
33 };
34 
35 #define IORING_FEAT_FLAGS (IORING_FEAT_SINGLE_MMAP |\
36 			IORING_FEAT_NODROP |\
37 			IORING_FEAT_SUBMIT_STABLE |\
38 			IORING_FEAT_RW_CUR_POS |\
39 			IORING_FEAT_CUR_PERSONALITY |\
40 			IORING_FEAT_FAST_POLL |\
41 			IORING_FEAT_POLL_32BITS |\
42 			IORING_FEAT_SQPOLL_NONFIXED |\
43 			IORING_FEAT_EXT_ARG |\
44 			IORING_FEAT_NATIVE_WORKERS |\
45 			IORING_FEAT_RSRC_TAGS |\
46 			IORING_FEAT_CQE_SKIP |\
47 			IORING_FEAT_LINKED_FILE |\
48 			IORING_FEAT_REG_REG_RING |\
49 			IORING_FEAT_RECVSEND_BUNDLE |\
50 			IORING_FEAT_MIN_TIMEOUT |\
51 			IORING_FEAT_RW_ATTR |\
52 			IORING_FEAT_NO_IOWAIT)
53 
54 #define IORING_SETUP_FLAGS (IORING_SETUP_IOPOLL |\
55 			IORING_SETUP_SQPOLL |\
56 			IORING_SETUP_SQ_AFF |\
57 			IORING_SETUP_CQSIZE |\
58 			IORING_SETUP_CLAMP |\
59 			IORING_SETUP_ATTACH_WQ |\
60 			IORING_SETUP_R_DISABLED |\
61 			IORING_SETUP_SUBMIT_ALL |\
62 			IORING_SETUP_COOP_TASKRUN |\
63 			IORING_SETUP_TASKRUN_FLAG |\
64 			IORING_SETUP_SQE128 |\
65 			IORING_SETUP_CQE32 |\
66 			IORING_SETUP_SINGLE_ISSUER |\
67 			IORING_SETUP_DEFER_TASKRUN |\
68 			IORING_SETUP_NO_MMAP |\
69 			IORING_SETUP_REGISTERED_FD_ONLY |\
70 			IORING_SETUP_NO_SQARRAY |\
71 			IORING_SETUP_HYBRID_IOPOLL |\
72 			IORING_SETUP_CQE_MIXED |\
73 			IORING_SETUP_SQE_MIXED |\
74 			IORING_SETUP_SQ_REWIND)
75 
76 #define IORING_ENTER_FLAGS (IORING_ENTER_GETEVENTS |\
77 			IORING_ENTER_SQ_WAKEUP |\
78 			IORING_ENTER_SQ_WAIT |\
79 			IORING_ENTER_EXT_ARG |\
80 			IORING_ENTER_REGISTERED_RING |\
81 			IORING_ENTER_ABS_TIMER |\
82 			IORING_ENTER_EXT_ARG_REG |\
83 			IORING_ENTER_NO_IOWAIT)
84 
85 
86 #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE |\
87 			IOSQE_IO_DRAIN |\
88 			IOSQE_IO_LINK |\
89 			IOSQE_IO_HARDLINK |\
90 			IOSQE_ASYNC |\
91 			IOSQE_BUFFER_SELECT |\
92 			IOSQE_CQE_SKIP_SUCCESS)
93 
94 #define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
95 
96 /*
97  * Complaint timeout for io_uring cancelation exits, and for io-wq exit
98  * worker waiting.
99  */
100 #define IO_URING_EXIT_WAIT_MAX	(HZ * 60 * 5)
101 
102 enum {
103 	IOU_COMPLETE		= 0,
104 
105 	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,
106 
107 	/*
108 	 * The request has more work to do and should be retried. io_uring will
109 	 * attempt to wait on the file for eligible opcodes, but otherwise
110 	 * it'll be handed to iowq for blocking execution. It works for normal
111 	 * requests as well as for the multi shot mode.
112 	 */
113 	IOU_RETRY		= -EAGAIN,
114 
115 	/*
116 	 * Requeue the task_work to restart operations on this request. The
117 	 * actual value isn't important, should just be not an otherwise
118 	 * valid error code, yet less than -MAX_ERRNO and valid internally.
119 	 */
120 	IOU_REQUEUE		= -3072,
121 };
122 
123 struct io_defer_entry {
124 	struct list_head	list;
125 	struct io_kiocb		*req;
126 };
127 
128 struct io_wait_queue {
129 	struct wait_queue_entry wq;
130 	struct io_ring_ctx *ctx;
131 	unsigned cq_tail;
132 	unsigned cq_min_tail;
133 	unsigned nr_timeouts;
134 	int hit_timeout;
135 	ktime_t min_timeout;
136 	ktime_t timeout;
137 	struct hrtimer t;
138 
139 #ifdef CONFIG_NET_RX_BUSY_POLL
140 	ktime_t napi_busy_poll_dt;
141 	bool napi_prefer_busy_poll;
142 #endif
143 };
144 
145 static inline struct io_rings *io_get_rings(struct io_ring_ctx *ctx)
146 {
147 	return rcu_dereference_check(ctx->rings_rcu,
148 			lockdep_is_held(&ctx->uring_lock) ||
149 			lockdep_is_held(&ctx->completion_lock));
150 }
151 
152 static inline bool io_should_wake(struct io_wait_queue *iowq)
153 {
154 	struct io_ring_ctx *ctx = iowq->ctx;
155 	struct io_rings *rings;
156 	int dist;
157 
158 	guard(rcu)();
159 	rings = io_get_rings(ctx);
160 
161 	/*
162 	 * Wake up if we have enough events, or if a timeout occurred since we
163 	 * started waiting. For timeouts, we always want to return to userspace,
164 	 * regardless of event count.
165 	 */
166 	dist = READ_ONCE(rings->cq.tail) - (int) iowq->cq_tail;
167 	return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
168 }
169 
170 #define IORING_MAX_ENTRIES	32768
171 #define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
172 
173 int io_prepare_config(struct io_ctx_config *config);
174 
175 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow, bool cqe32);
176 void io_req_defer_failed(struct io_kiocb *req, s32 res);
177 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
178 void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
179 bool io_req_post_cqe(struct io_kiocb *req, s32 res, u32 cflags);
180 bool io_req_post_cqe32(struct io_kiocb *req, struct io_uring_cqe src_cqe[2]);
181 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
182 
183 unsigned io_linked_nr(struct io_kiocb *req);
184 void io_req_track_inflight(struct io_kiocb *req);
185 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
186 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
187 			       unsigned issue_flags);
188 
189 void io_req_task_queue(struct io_kiocb *req);
190 void io_req_task_complete(struct io_tw_req tw_req, io_tw_token_t tw);
191 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
192 void io_req_task_submit(struct io_tw_req tw_req, io_tw_token_t tw);
193 __cold void io_uring_drop_tctx_refs(struct task_struct *task);
194 
195 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
196 				     int start, int end);
197 void io_req_queue_iowq(struct io_kiocb *req);
198 
199 int io_poll_issue(struct io_kiocb *req, io_tw_token_t tw);
200 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
201 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
202 __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx);
203 void __io_submit_flush_completions(struct io_ring_ctx *ctx);
204 
205 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
206 void io_wq_submit_work(struct io_wq_work *work);
207 
208 void io_free_req(struct io_kiocb *req);
209 void io_queue_next(struct io_kiocb *req);
210 void io_task_refs_refill(struct io_uring_task *tctx);
211 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
212 
213 void io_activate_pollwq(struct io_ring_ctx *ctx);
214 void io_restriction_clone(struct io_restriction *dst, struct io_restriction *src);
215 
216 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
217 {
218 #if defined(CONFIG_PROVE_LOCKING)
219 	lockdep_assert(in_task());
220 
221 	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
222 		lockdep_assert_held(&ctx->uring_lock);
223 
224 	if (ctx->flags & IORING_SETUP_IOPOLL) {
225 		lockdep_assert_held(&ctx->uring_lock);
226 	} else if (!ctx->task_complete) {
227 		lockdep_assert_held(&ctx->completion_lock);
228 	} else if (ctx->submitter_task) {
229 		/*
230 		 * ->submitter_task may be NULL and we can still post a CQE,
231 		 * if the ring has been setup with IORING_SETUP_R_DISABLED.
232 		 * Not from an SQE, as those cannot be submitted, but via
233 		 * updating tagged resources.
234 		 */
235 		if (!percpu_ref_is_dying(&ctx->refs))
236 			lockdep_assert(current == ctx->submitter_task);
237 	}
238 #endif
239 }
240 
241 static inline bool io_is_compat(struct io_ring_ctx *ctx)
242 {
243 	return IS_ENABLED(CONFIG_COMPAT) && unlikely(ctx->compat);
244 }
245 
246 static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
247 {
248 	if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
249 	    ctx->submit_state.cq_flush)
250 		__io_submit_flush_completions(ctx);
251 }
252 
253 #define io_for_each_link(pos, head) \
254 	for (pos = (head); pos; pos = pos->link)
255 
256 static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
257 					struct io_uring_cqe **ret,
258 					bool overflow, bool cqe32)
259 {
260 	io_lockdep_assert_cq_locked(ctx);
261 
262 	if (unlikely(ctx->cqe_sentinel - ctx->cqe_cached < (cqe32 + 1))) {
263 		if (unlikely(!io_cqe_cache_refill(ctx, overflow, cqe32)))
264 			return false;
265 	}
266 	*ret = ctx->cqe_cached;
267 	ctx->cached_cq_tail++;
268 	ctx->cqe_cached++;
269 	if (ctx->flags & IORING_SETUP_CQE32) {
270 		ctx->cqe_cached++;
271 	} else if (cqe32 && ctx->flags & IORING_SETUP_CQE_MIXED) {
272 		ctx->cqe_cached++;
273 		ctx->cached_cq_tail++;
274 	}
275 	WARN_ON_ONCE(ctx->cqe_cached > ctx->cqe_sentinel);
276 	return true;
277 }
278 
279 static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret,
280 				bool cqe32)
281 {
282 	return io_get_cqe_overflow(ctx, ret, false, cqe32);
283 }
284 
285 static inline bool io_defer_get_uncommited_cqe(struct io_ring_ctx *ctx,
286 					       struct io_uring_cqe **cqe_ret)
287 {
288 	io_lockdep_assert_cq_locked(ctx);
289 
290 	ctx->submit_state.cq_flush = true;
291 	return io_get_cqe(ctx, cqe_ret, ctx->flags & IORING_SETUP_CQE_MIXED);
292 }
293 
294 static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
295 					    struct io_kiocb *req)
296 {
297 	bool is_cqe32 = req->cqe.flags & IORING_CQE_F_32;
298 	struct io_uring_cqe *cqe;
299 
300 	/*
301 	 * If we can't get a cq entry, userspace overflowed the submission
302 	 * (by quite a lot).
303 	 */
304 	if (unlikely(!io_get_cqe(ctx, &cqe, is_cqe32)))
305 		return false;
306 
307 	memcpy(cqe, &req->cqe, sizeof(*cqe));
308 	if (ctx->flags & IORING_SETUP_CQE32 || is_cqe32) {
309 		memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
310 		memset(&req->big_cqe, 0, sizeof(req->big_cqe));
311 	}
312 
313 	if (trace_io_uring_complete_enabled())
314 		trace_io_uring_complete(req->ctx, req, cqe);
315 	return true;
316 }
317 
318 static inline void req_set_fail(struct io_kiocb *req)
319 {
320 	req->flags |= REQ_F_FAIL;
321 	if (req->flags & REQ_F_CQE_SKIP) {
322 		req->flags &= ~REQ_F_CQE_SKIP;
323 		req->flags |= REQ_F_SKIP_LINK_CQES;
324 	}
325 }
326 
327 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
328 {
329 	req->cqe.res = res;
330 	req->cqe.flags = cflags;
331 }
332 
333 static inline u32 ctx_cqe32_flags(struct io_ring_ctx *ctx)
334 {
335 	if (ctx->flags & IORING_SETUP_CQE_MIXED)
336 		return IORING_CQE_F_32;
337 	return 0;
338 }
339 
340 static inline void io_req_set_res32(struct io_kiocb *req, s32 res, u32 cflags,
341 				    __u64 extra1, __u64 extra2)
342 {
343 	req->cqe.res = res;
344 	req->cqe.flags = cflags | ctx_cqe32_flags(req->ctx);
345 	req->big_cqe.extra1 = extra1;
346 	req->big_cqe.extra2 = extra2;
347 }
348 
349 static inline void *io_uring_alloc_async_data(struct io_alloc_cache *cache,
350 					      struct io_kiocb *req)
351 {
352 	if (cache) {
353 		req->async_data = io_cache_alloc(cache, GFP_KERNEL);
354 	} else {
355 		const struct io_issue_def *def = &io_issue_defs[req->opcode];
356 
357 		WARN_ON_ONCE(!def->async_size);
358 		req->async_data = kmalloc(def->async_size, GFP_KERNEL);
359 	}
360 	if (req->async_data)
361 		req->flags |= REQ_F_ASYNC_DATA;
362 	return req->async_data;
363 }
364 
365 static inline bool req_has_async_data(struct io_kiocb *req)
366 {
367 	return req->flags & REQ_F_ASYNC_DATA;
368 }
369 
370 static inline void io_req_async_data_clear(struct io_kiocb *req,
371 					   io_req_flags_t extra_flags)
372 {
373 	req->flags &= ~(REQ_F_ASYNC_DATA|extra_flags);
374 	req->async_data = NULL;
375 }
376 
377 static inline void io_req_async_data_free(struct io_kiocb *req)
378 {
379 	kfree(req->async_data);
380 	io_req_async_data_clear(req, 0);
381 }
382 
383 static inline void io_put_file(struct io_kiocb *req)
384 {
385 	if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
386 		fput(req->file);
387 }
388 
389 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
390 					 unsigned issue_flags)
391 {
392 	lockdep_assert_held(&ctx->uring_lock);
393 	if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
394 		mutex_unlock(&ctx->uring_lock);
395 }
396 
397 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
398 				       unsigned issue_flags)
399 {
400 	/*
401 	 * "Normal" inline submissions always hold the uring_lock, since we
402 	 * grab it from the system call. Same is true for the SQPOLL offload.
403 	 * The only exception is when we've detached the request and issue it
404 	 * from an async worker thread, grab the lock for that case.
405 	 */
406 	if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
407 		mutex_lock(&ctx->uring_lock);
408 	lockdep_assert_held(&ctx->uring_lock);
409 }
410 
411 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
412 {
413 	/* order cqe stores with ring update */
414 	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
415 }
416 
417 static inline void __io_wq_wake(struct wait_queue_head *wq)
418 {
419 	/*
420 	 *
421 	 * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
422 	 * set in the mask so that if we recurse back into our own poll
423 	 * waitqueue handlers, we know we have a dependency between eventfd or
424 	 * epoll and should terminate multishot poll at that point.
425 	 */
426 	if (wq_has_sleeper(wq))
427 		__wake_up(wq, TASK_NORMAL, 0, poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
428 }
429 
430 static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
431 {
432 	__io_wq_wake(&ctx->poll_wq);
433 }
434 
435 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
436 {
437 	/*
438 	 * Trigger waitqueue handler on all waiters on our waitqueue. This
439 	 * won't necessarily wake up all the tasks, io_should_wake() will make
440 	 * that decision.
441 	 */
442 
443 	__io_wq_wake(&ctx->cq_wait);
444 }
445 
446 static inline bool __io_sqring_full(struct io_ring_ctx *ctx)
447 {
448 	struct io_rings *r = io_get_rings(ctx);
449 
450 	/*
451 	 * SQPOLL must use the actual sqring head, as using the cached_sq_head
452 	 * is race prone if the SQPOLL thread has grabbed entries but not yet
453 	 * committed them to the ring. For !SQPOLL, this doesn't matter, but
454 	 * since this helper is just used for SQPOLL sqring waits (or POLLOUT),
455 	 * just read the actual sqring head unconditionally.
456 	 */
457 	return READ_ONCE(r->sq.tail) - READ_ONCE(r->sq.head) == ctx->sq_entries;
458 }
459 
460 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
461 {
462 	guard(rcu)();
463 	return __io_sqring_full(ctx);
464 }
465 
466 static inline unsigned int __io_sqring_entries(struct io_ring_ctx *ctx)
467 {
468 	struct io_rings *rings = io_get_rings(ctx);
469 	unsigned int entries;
470 
471 	/* make sure SQ entry isn't read before tail */
472 	entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
473 	return min(entries, ctx->sq_entries);
474 }
475 
476 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
477 {
478 	guard(rcu)();
479 	return __io_sqring_entries(ctx);
480 }
481 
482 /*
483  * Don't complete immediately but use deferred completion infrastructure.
484  * Protected by ->uring_lock and can only be used either with
485  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
486  */
487 static inline void io_req_complete_defer(struct io_kiocb *req)
488 	__must_hold(&req->ctx->uring_lock)
489 {
490 	struct io_submit_state *state = &req->ctx->submit_state;
491 
492 	lockdep_assert_held(&req->ctx->uring_lock);
493 
494 	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
495 }
496 
497 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
498 {
499 	if (unlikely(ctx->off_timeout_used ||
500 		     ctx->has_evfd || ctx->poll_activated))
501 		__io_commit_cqring_flush(ctx);
502 }
503 
504 static inline void io_get_task_refs(int nr)
505 {
506 	struct io_uring_task *tctx = current->io_uring;
507 
508 	tctx->cached_refs -= nr;
509 	if (unlikely(tctx->cached_refs < 0))
510 		io_task_refs_refill(tctx);
511 }
512 
513 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
514 {
515 	return !ctx->submit_state.free_list.next;
516 }
517 
518 extern struct kmem_cache *req_cachep;
519 
520 static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
521 {
522 	struct io_kiocb *req;
523 
524 	req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
525 	wq_stack_extract(&ctx->submit_state.free_list);
526 	return req;
527 }
528 
529 static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
530 {
531 	if (unlikely(io_req_cache_empty(ctx))) {
532 		if (!__io_alloc_req_refill(ctx))
533 			return false;
534 	}
535 	*req = io_extract_req(ctx);
536 	return true;
537 }
538 
539 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
540 {
541 	io_req_set_res(req, res, 0);
542 	req->io_task_work.func = io_req_task_complete;
543 	io_req_task_work_add(req);
544 }
545 
546 static inline bool io_file_can_poll(struct io_kiocb *req)
547 {
548 	if (req->flags & REQ_F_CAN_POLL)
549 		return true;
550 	if (req->file && file_can_poll(req->file)) {
551 		req->flags |= REQ_F_CAN_POLL;
552 		return true;
553 	}
554 	return false;
555 }
556 
557 static inline bool io_is_uring_cmd(const struct io_kiocb *req)
558 {
559 	return req->opcode == IORING_OP_URING_CMD ||
560 	       req->opcode == IORING_OP_URING_CMD128;
561 }
562 
563 static inline ktime_t io_get_time(struct io_ring_ctx *ctx)
564 {
565 	if (ctx->clockid == CLOCK_MONOTONIC)
566 		return ktime_get();
567 
568 	return ktime_get_with_offset(ctx->clock_offset);
569 }
570 
571 enum {
572 	IO_CHECK_CQ_OVERFLOW_BIT,
573 	IO_CHECK_CQ_DROPPED_BIT,
574 };
575 
576 static inline bool io_has_work(struct io_ring_ctx *ctx)
577 {
578 	return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
579 	       io_local_work_pending(ctx);
580 }
581 #endif
582