xref: /linux/io_uring/io_uring.h (revision 2c1ed907520c50326b8f604907a8478b27881a2e)
1 #ifndef IOU_CORE_H
2 #define IOU_CORE_H
3 
4 #include <linux/errno.h>
5 #include <linux/lockdep.h>
6 #include <linux/resume_user_mode.h>
7 #include <linux/kasan.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 "filetable.h"
15 #include "opdef.h"
16 
17 #ifndef CREATE_TRACE_POINTS
18 #include <trace/events/io_uring.h>
19 #endif
20 
21 enum {
22 	IOU_OK			= 0,
23 	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,
24 
25 	/*
26 	 * Requeue the task_work to restart operations on this request. The
27 	 * actual value isn't important, should just be not an otherwise
28 	 * valid error code, yet less than -MAX_ERRNO and valid internally.
29 	 */
30 	IOU_REQUEUE		= -3072,
31 
32 	/*
33 	 * Intended only when both IO_URING_F_MULTISHOT is passed
34 	 * to indicate to the poll runner that multishot should be
35 	 * removed and the result is set on req->cqe.res.
36 	 */
37 	IOU_STOP_MULTISHOT	= -ECANCELED,
38 };
39 
40 struct io_wait_queue {
41 	struct wait_queue_entry wq;
42 	struct io_ring_ctx *ctx;
43 	unsigned cq_tail;
44 	unsigned cq_min_tail;
45 	unsigned nr_timeouts;
46 	int hit_timeout;
47 	ktime_t min_timeout;
48 	ktime_t timeout;
49 	struct hrtimer t;
50 
51 #ifdef CONFIG_NET_RX_BUSY_POLL
52 	ktime_t napi_busy_poll_dt;
53 	bool napi_prefer_busy_poll;
54 #endif
55 };
56 
io_should_wake(struct io_wait_queue * iowq)57 static inline bool io_should_wake(struct io_wait_queue *iowq)
58 {
59 	struct io_ring_ctx *ctx = iowq->ctx;
60 	int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
61 
62 	/*
63 	 * Wake up if we have enough events, or if a timeout occurred since we
64 	 * started waiting. For timeouts, we always want to return to userspace,
65 	 * regardless of event count.
66 	 */
67 	return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
68 }
69 
70 #define IORING_MAX_ENTRIES	32768
71 #define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)
72 
73 unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
74 			 unsigned int cq_entries, size_t *sq_offset);
75 int io_uring_fill_params(unsigned entries, struct io_uring_params *p);
76 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
77 int io_run_task_work_sig(struct io_ring_ctx *ctx);
78 void io_req_defer_failed(struct io_kiocb *req, s32 res);
79 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
80 void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
81 bool io_req_post_cqe(struct io_kiocb *req, s32 res, u32 cflags);
82 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
83 
84 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
85 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
86 			       unsigned issue_flags);
87 
88 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
89 void io_req_task_work_add_remote(struct io_kiocb *req, struct io_ring_ctx *ctx,
90 				 unsigned flags);
91 bool io_alloc_async_data(struct io_kiocb *req);
92 void io_req_task_queue(struct io_kiocb *req);
93 void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
94 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
95 void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
96 struct llist_node *io_handle_tw_list(struct llist_node *node, unsigned int *count, unsigned int max_entries);
97 struct llist_node *tctx_task_work_run(struct io_uring_task *tctx, unsigned int max_entries, unsigned int *count);
98 void tctx_task_work(struct callback_head *cb);
99 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
100 int io_uring_alloc_task_context(struct task_struct *task,
101 				struct io_ring_ctx *ctx);
102 
103 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
104 				     int start, int end);
105 void io_req_queue_iowq(struct io_kiocb *req);
106 
107 int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts);
108 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
109 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
110 void __io_submit_flush_completions(struct io_ring_ctx *ctx);
111 
112 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
113 void io_wq_submit_work(struct io_wq_work *work);
114 
115 void io_free_req(struct io_kiocb *req);
116 void io_queue_next(struct io_kiocb *req);
117 void io_task_refs_refill(struct io_uring_task *tctx);
118 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
119 
120 bool io_match_task_safe(struct io_kiocb *head, struct io_uring_task *tctx,
121 			bool cancel_all);
122 
123 void io_activate_pollwq(struct io_ring_ctx *ctx);
124 
io_lockdep_assert_cq_locked(struct io_ring_ctx * ctx)125 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
126 {
127 #if defined(CONFIG_PROVE_LOCKING)
128 	lockdep_assert(in_task());
129 
130 	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
131 		lockdep_assert_held(&ctx->uring_lock);
132 
133 	if (ctx->flags & IORING_SETUP_IOPOLL) {
134 		lockdep_assert_held(&ctx->uring_lock);
135 	} else if (!ctx->task_complete) {
136 		lockdep_assert_held(&ctx->completion_lock);
137 	} else if (ctx->submitter_task) {
138 		/*
139 		 * ->submitter_task may be NULL and we can still post a CQE,
140 		 * if the ring has been setup with IORING_SETUP_R_DISABLED.
141 		 * Not from an SQE, as those cannot be submitted, but via
142 		 * updating tagged resources.
143 		 */
144 		if (!percpu_ref_is_dying(&ctx->refs))
145 			lockdep_assert(current == ctx->submitter_task);
146 	}
147 #endif
148 }
149 
io_req_task_work_add(struct io_kiocb * req)150 static inline void io_req_task_work_add(struct io_kiocb *req)
151 {
152 	__io_req_task_work_add(req, 0);
153 }
154 
io_submit_flush_completions(struct io_ring_ctx * ctx)155 static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
156 {
157 	if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
158 	    ctx->submit_state.cq_flush)
159 		__io_submit_flush_completions(ctx);
160 }
161 
162 #define io_for_each_link(pos, head) \
163 	for (pos = (head); pos; pos = pos->link)
164 
io_get_cqe_overflow(struct io_ring_ctx * ctx,struct io_uring_cqe ** ret,bool overflow)165 static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
166 					struct io_uring_cqe **ret,
167 					bool overflow)
168 {
169 	io_lockdep_assert_cq_locked(ctx);
170 
171 	if (unlikely(ctx->cqe_cached >= ctx->cqe_sentinel)) {
172 		if (unlikely(!io_cqe_cache_refill(ctx, overflow)))
173 			return false;
174 	}
175 	*ret = ctx->cqe_cached;
176 	ctx->cached_cq_tail++;
177 	ctx->cqe_cached++;
178 	if (ctx->flags & IORING_SETUP_CQE32)
179 		ctx->cqe_cached++;
180 	return true;
181 }
182 
io_get_cqe(struct io_ring_ctx * ctx,struct io_uring_cqe ** ret)183 static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret)
184 {
185 	return io_get_cqe_overflow(ctx, ret, false);
186 }
187 
io_fill_cqe_req(struct io_ring_ctx * ctx,struct io_kiocb * req)188 static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
189 					    struct io_kiocb *req)
190 {
191 	struct io_uring_cqe *cqe;
192 
193 	/*
194 	 * If we can't get a cq entry, userspace overflowed the
195 	 * submission (by quite a lot). Increment the overflow count in
196 	 * the ring.
197 	 */
198 	if (unlikely(!io_get_cqe(ctx, &cqe)))
199 		return false;
200 
201 
202 	memcpy(cqe, &req->cqe, sizeof(*cqe));
203 	if (ctx->flags & IORING_SETUP_CQE32) {
204 		memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
205 		memset(&req->big_cqe, 0, sizeof(req->big_cqe));
206 	}
207 
208 	if (trace_io_uring_complete_enabled())
209 		trace_io_uring_complete(req->ctx, req, cqe);
210 	return true;
211 }
212 
req_set_fail(struct io_kiocb * req)213 static inline void req_set_fail(struct io_kiocb *req)
214 {
215 	req->flags |= REQ_F_FAIL;
216 	if (req->flags & REQ_F_CQE_SKIP) {
217 		req->flags &= ~REQ_F_CQE_SKIP;
218 		req->flags |= REQ_F_SKIP_LINK_CQES;
219 	}
220 }
221 
io_req_set_res(struct io_kiocb * req,s32 res,u32 cflags)222 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
223 {
224 	req->cqe.res = res;
225 	req->cqe.flags = cflags;
226 }
227 
io_uring_alloc_async_data(struct io_alloc_cache * cache,struct io_kiocb * req)228 static inline void *io_uring_alloc_async_data(struct io_alloc_cache *cache,
229 					      struct io_kiocb *req)
230 {
231 	if (cache) {
232 		req->async_data = io_cache_alloc(cache, GFP_KERNEL);
233 	} else {
234 		const struct io_issue_def *def = &io_issue_defs[req->opcode];
235 
236 		WARN_ON_ONCE(!def->async_size);
237 		req->async_data = kmalloc(def->async_size, GFP_KERNEL);
238 	}
239 	if (req->async_data)
240 		req->flags |= REQ_F_ASYNC_DATA;
241 	return req->async_data;
242 }
243 
req_has_async_data(struct io_kiocb * req)244 static inline bool req_has_async_data(struct io_kiocb *req)
245 {
246 	return req->flags & REQ_F_ASYNC_DATA;
247 }
248 
io_put_file(struct io_kiocb * req)249 static inline void io_put_file(struct io_kiocb *req)
250 {
251 	if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
252 		fput(req->file);
253 }
254 
io_ring_submit_unlock(struct io_ring_ctx * ctx,unsigned issue_flags)255 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
256 					 unsigned issue_flags)
257 {
258 	lockdep_assert_held(&ctx->uring_lock);
259 	if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
260 		mutex_unlock(&ctx->uring_lock);
261 }
262 
io_ring_submit_lock(struct io_ring_ctx * ctx,unsigned issue_flags)263 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
264 				       unsigned issue_flags)
265 {
266 	/*
267 	 * "Normal" inline submissions always hold the uring_lock, since we
268 	 * grab it from the system call. Same is true for the SQPOLL offload.
269 	 * The only exception is when we've detached the request and issue it
270 	 * from an async worker thread, grab the lock for that case.
271 	 */
272 	if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
273 		mutex_lock(&ctx->uring_lock);
274 	lockdep_assert_held(&ctx->uring_lock);
275 }
276 
io_commit_cqring(struct io_ring_ctx * ctx)277 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
278 {
279 	/* order cqe stores with ring update */
280 	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
281 }
282 
io_poll_wq_wake(struct io_ring_ctx * ctx)283 static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
284 {
285 	if (wq_has_sleeper(&ctx->poll_wq))
286 		__wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
287 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
288 }
289 
io_cqring_wake(struct io_ring_ctx * ctx)290 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
291 {
292 	/*
293 	 * Trigger waitqueue handler on all waiters on our waitqueue. This
294 	 * won't necessarily wake up all the tasks, io_should_wake() will make
295 	 * that decision.
296 	 *
297 	 * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
298 	 * set in the mask so that if we recurse back into our own poll
299 	 * waitqueue handlers, we know we have a dependency between eventfd or
300 	 * epoll and should terminate multishot poll at that point.
301 	 */
302 	if (wq_has_sleeper(&ctx->cq_wait))
303 		__wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
304 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
305 }
306 
io_sqring_full(struct io_ring_ctx * ctx)307 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
308 {
309 	struct io_rings *r = ctx->rings;
310 
311 	/*
312 	 * SQPOLL must use the actual sqring head, as using the cached_sq_head
313 	 * is race prone if the SQPOLL thread has grabbed entries but not yet
314 	 * committed them to the ring. For !SQPOLL, this doesn't matter, but
315 	 * since this helper is just used for SQPOLL sqring waits (or POLLOUT),
316 	 * just read the actual sqring head unconditionally.
317 	 */
318 	return READ_ONCE(r->sq.tail) - READ_ONCE(r->sq.head) == ctx->sq_entries;
319 }
320 
io_sqring_entries(struct io_ring_ctx * ctx)321 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
322 {
323 	struct io_rings *rings = ctx->rings;
324 	unsigned int entries;
325 
326 	/* make sure SQ entry isn't read before tail */
327 	entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
328 	return min(entries, ctx->sq_entries);
329 }
330 
io_run_task_work(void)331 static inline int io_run_task_work(void)
332 {
333 	bool ret = false;
334 
335 	/*
336 	 * Always check-and-clear the task_work notification signal. With how
337 	 * signaling works for task_work, we can find it set with nothing to
338 	 * run. We need to clear it for that case, like get_signal() does.
339 	 */
340 	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
341 		clear_notify_signal();
342 	/*
343 	 * PF_IO_WORKER never returns to userspace, so check here if we have
344 	 * notify work that needs processing.
345 	 */
346 	if (current->flags & PF_IO_WORKER) {
347 		if (test_thread_flag(TIF_NOTIFY_RESUME)) {
348 			__set_current_state(TASK_RUNNING);
349 			resume_user_mode_work(NULL);
350 		}
351 		if (current->io_uring) {
352 			unsigned int count = 0;
353 
354 			__set_current_state(TASK_RUNNING);
355 			tctx_task_work_run(current->io_uring, UINT_MAX, &count);
356 			if (count)
357 				ret = true;
358 		}
359 	}
360 	if (task_work_pending(current)) {
361 		__set_current_state(TASK_RUNNING);
362 		task_work_run();
363 		ret = true;
364 	}
365 
366 	return ret;
367 }
368 
io_local_work_pending(struct io_ring_ctx * ctx)369 static inline bool io_local_work_pending(struct io_ring_ctx *ctx)
370 {
371 	return !llist_empty(&ctx->work_llist) || !llist_empty(&ctx->retry_llist);
372 }
373 
io_task_work_pending(struct io_ring_ctx * ctx)374 static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
375 {
376 	return task_work_pending(current) || io_local_work_pending(ctx);
377 }
378 
io_tw_lock(struct io_ring_ctx * ctx,struct io_tw_state * ts)379 static inline void io_tw_lock(struct io_ring_ctx *ctx, struct io_tw_state *ts)
380 {
381 	lockdep_assert_held(&ctx->uring_lock);
382 }
383 
384 /*
385  * Don't complete immediately but use deferred completion infrastructure.
386  * Protected by ->uring_lock and can only be used either with
387  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
388  */
io_req_complete_defer(struct io_kiocb * req)389 static inline void io_req_complete_defer(struct io_kiocb *req)
390 	__must_hold(&req->ctx->uring_lock)
391 {
392 	struct io_submit_state *state = &req->ctx->submit_state;
393 
394 	lockdep_assert_held(&req->ctx->uring_lock);
395 
396 	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
397 }
398 
io_commit_cqring_flush(struct io_ring_ctx * ctx)399 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
400 {
401 	if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
402 		     ctx->has_evfd || ctx->poll_activated))
403 		__io_commit_cqring_flush(ctx);
404 }
405 
io_get_task_refs(int nr)406 static inline void io_get_task_refs(int nr)
407 {
408 	struct io_uring_task *tctx = current->io_uring;
409 
410 	tctx->cached_refs -= nr;
411 	if (unlikely(tctx->cached_refs < 0))
412 		io_task_refs_refill(tctx);
413 }
414 
io_req_cache_empty(struct io_ring_ctx * ctx)415 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
416 {
417 	return !ctx->submit_state.free_list.next;
418 }
419 
420 extern struct kmem_cache *req_cachep;
421 extern struct kmem_cache *io_buf_cachep;
422 
io_extract_req(struct io_ring_ctx * ctx)423 static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
424 {
425 	struct io_kiocb *req;
426 
427 	req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
428 	wq_stack_extract(&ctx->submit_state.free_list);
429 	return req;
430 }
431 
io_alloc_req(struct io_ring_ctx * ctx,struct io_kiocb ** req)432 static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
433 {
434 	if (unlikely(io_req_cache_empty(ctx))) {
435 		if (!__io_alloc_req_refill(ctx))
436 			return false;
437 	}
438 	*req = io_extract_req(ctx);
439 	return true;
440 }
441 
io_allowed_defer_tw_run(struct io_ring_ctx * ctx)442 static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
443 {
444 	return likely(ctx->submitter_task == current);
445 }
446 
io_allowed_run_tw(struct io_ring_ctx * ctx)447 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
448 {
449 	return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
450 		      ctx->submitter_task == current);
451 }
452 
453 /*
454  * Terminate the request if either of these conditions are true:
455  *
456  * 1) It's being executed by the original task, but that task is marked
457  *    with PF_EXITING as it's exiting.
458  * 2) PF_KTHREAD is set, in which case the invoker of the task_work is
459  *    our fallback task_work.
460  */
io_should_terminate_tw(void)461 static inline bool io_should_terminate_tw(void)
462 {
463 	return current->flags & (PF_KTHREAD | PF_EXITING);
464 }
465 
io_req_queue_tw_complete(struct io_kiocb * req,s32 res)466 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
467 {
468 	io_req_set_res(req, res, 0);
469 	req->io_task_work.func = io_req_task_complete;
470 	io_req_task_work_add(req);
471 }
472 
473 /*
474  * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
475  * slot.
476  */
uring_sqe_size(struct io_ring_ctx * ctx)477 static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
478 {
479 	if (ctx->flags & IORING_SETUP_SQE128)
480 		return 2 * sizeof(struct io_uring_sqe);
481 	return sizeof(struct io_uring_sqe);
482 }
483 
io_file_can_poll(struct io_kiocb * req)484 static inline bool io_file_can_poll(struct io_kiocb *req)
485 {
486 	if (req->flags & REQ_F_CAN_POLL)
487 		return true;
488 	if (req->file && file_can_poll(req->file)) {
489 		req->flags |= REQ_F_CAN_POLL;
490 		return true;
491 	}
492 	return false;
493 }
494 
io_get_time(struct io_ring_ctx * ctx)495 static inline ktime_t io_get_time(struct io_ring_ctx *ctx)
496 {
497 	if (ctx->clockid == CLOCK_MONOTONIC)
498 		return ktime_get();
499 
500 	return ktime_get_with_offset(ctx->clock_offset);
501 }
502 
503 enum {
504 	IO_CHECK_CQ_OVERFLOW_BIT,
505 	IO_CHECK_CQ_DROPPED_BIT,
506 };
507 
io_has_work(struct io_ring_ctx * ctx)508 static inline bool io_has_work(struct io_ring_ctx *ctx)
509 {
510 	return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
511 	       io_local_work_pending(ctx);
512 }
513 #endif
514