xref: /linux/io_uring/io_uring.h (revision fd7d598270724cc787982ea48bbe17ad383a8b7f) 
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/io_uring_types.h>
9 #include <uapi/linux/eventpoll.h>
10 #include "io-wq.h"
11 #include "slist.h"
12 #include "filetable.h"
13 
14 #ifndef CREATE_TRACE_POINTS
15 #include <trace/events/io_uring.h>
16 #endif
17 
18 enum {
19 	/*
20 	 * A hint to not wake right away but delay until there are enough of
21 	 * tw's queued to match the number of CQEs the task is waiting for.
22 	 *
23 	 * Must not be used wirh requests generating more than one CQE.
24 	 * It's also ignored unless IORING_SETUP_DEFER_TASKRUN is set.
25 	 */
26 	IOU_F_TWQ_LAZY_WAKE			= 1,
27 };
28 
29 enum {
30 	IOU_OK			= 0,
31 	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,
32 
33 	/*
34 	 * Intended only when both IO_URING_F_MULTISHOT is passed
35 	 * to indicate to the poll runner that multishot should be
36 	 * removed and the result is set on req->cqe.res.
37 	 */
38 	IOU_STOP_MULTISHOT	= -ECANCELED,
39 };
40 
41 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
42 void io_req_cqe_overflow(struct io_kiocb *req);
43 int io_run_task_work_sig(struct io_ring_ctx *ctx);
44 void io_req_defer_failed(struct io_kiocb *req, s32 res);
45 void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags);
46 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
47 bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags);
48 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
49 
50 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
51 
52 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
53 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
54 			       unsigned issue_flags);
55 
56 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
57 bool io_is_uring_fops(struct file *file);
58 bool io_alloc_async_data(struct io_kiocb *req);
59 void io_req_task_queue(struct io_kiocb *req);
60 void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use);
61 void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
62 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
63 void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
64 void tctx_task_work(struct callback_head *cb);
65 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
66 int io_uring_alloc_task_context(struct task_struct *task,
67 				struct io_ring_ctx *ctx);
68 
69 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
70 				     int start, int end);
71 
72 int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts);
73 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
74 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
75 void __io_submit_flush_completions(struct io_ring_ctx *ctx);
76 int io_req_prep_async(struct io_kiocb *req);
77 
78 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
79 void io_wq_submit_work(struct io_wq_work *work);
80 
81 void io_free_req(struct io_kiocb *req);
82 void io_queue_next(struct io_kiocb *req);
83 void io_task_refs_refill(struct io_uring_task *tctx);
84 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
85 
86 bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
87 			bool cancel_all);
88 
89 #if defined(CONFIG_PROVE_LOCKING)
90 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
91 {
92 	lockdep_assert(in_task());
93 
94 	if (ctx->flags & IORING_SETUP_IOPOLL) {
95 		lockdep_assert_held(&ctx->uring_lock);
96 	} else if (!ctx->task_complete) {
97 		lockdep_assert_held(&ctx->completion_lock);
98 	} else if (ctx->submitter_task) {
99 		/*
100 		 * ->submitter_task may be NULL and we can still post a CQE,
101 		 * if the ring has been setup with IORING_SETUP_R_DISABLED.
102 		 * Not from an SQE, as those cannot be submitted, but via
103 		 * updating tagged resources.
104 		 */
105 		if (ctx->submitter_task->flags & PF_EXITING)
106 			lockdep_assert(current_work());
107 		else
108 			lockdep_assert(current == ctx->submitter_task);
109 	}
110 }
111 #else
112 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
113 {
114 }
115 #endif
116 
117 static inline void io_req_task_work_add(struct io_kiocb *req)
118 {
119 	__io_req_task_work_add(req, 0);
120 }
121 
122 #define io_for_each_link(pos, head) \
123 	for (pos = (head); pos; pos = pos->link)
124 
125 static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
126 					struct io_uring_cqe **ret,
127 					bool overflow)
128 {
129 	io_lockdep_assert_cq_locked(ctx);
130 
131 	if (unlikely(ctx->cqe_cached >= ctx->cqe_sentinel)) {
132 		if (unlikely(!io_cqe_cache_refill(ctx, overflow)))
133 			return false;
134 	}
135 	*ret = ctx->cqe_cached;
136 	ctx->cached_cq_tail++;
137 	ctx->cqe_cached++;
138 	if (ctx->flags & IORING_SETUP_CQE32)
139 		ctx->cqe_cached++;
140 	return true;
141 }
142 
143 static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret)
144 {
145 	return io_get_cqe_overflow(ctx, ret, false);
146 }
147 
148 static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
149 					    struct io_kiocb *req)
150 {
151 	struct io_uring_cqe *cqe;
152 
153 	/*
154 	 * If we can't get a cq entry, userspace overflowed the
155 	 * submission (by quite a lot). Increment the overflow count in
156 	 * the ring.
157 	 */
158 	if (unlikely(!io_get_cqe(ctx, &cqe)))
159 		return false;
160 
161 	if (trace_io_uring_complete_enabled())
162 		trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
163 					req->cqe.res, req->cqe.flags,
164 					req->big_cqe.extra1, req->big_cqe.extra2);
165 
166 	memcpy(cqe, &req->cqe, sizeof(*cqe));
167 	if (ctx->flags & IORING_SETUP_CQE32) {
168 		memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
169 		memset(&req->big_cqe, 0, sizeof(req->big_cqe));
170 	}
171 	return true;
172 }
173 
174 static inline void req_set_fail(struct io_kiocb *req)
175 {
176 	req->flags |= REQ_F_FAIL;
177 	if (req->flags & REQ_F_CQE_SKIP) {
178 		req->flags &= ~REQ_F_CQE_SKIP;
179 		req->flags |= REQ_F_SKIP_LINK_CQES;
180 	}
181 }
182 
183 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
184 {
185 	req->cqe.res = res;
186 	req->cqe.flags = cflags;
187 }
188 
189 static inline bool req_has_async_data(struct io_kiocb *req)
190 {
191 	return req->flags & REQ_F_ASYNC_DATA;
192 }
193 
194 static inline void io_put_file(struct io_kiocb *req)
195 {
196 	if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
197 		fput(req->file);
198 }
199 
200 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
201 					 unsigned issue_flags)
202 {
203 	lockdep_assert_held(&ctx->uring_lock);
204 	if (issue_flags & IO_URING_F_UNLOCKED)
205 		mutex_unlock(&ctx->uring_lock);
206 }
207 
208 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
209 				       unsigned issue_flags)
210 {
211 	/*
212 	 * "Normal" inline submissions always hold the uring_lock, since we
213 	 * grab it from the system call. Same is true for the SQPOLL offload.
214 	 * The only exception is when we've detached the request and issue it
215 	 * from an async worker thread, grab the lock for that case.
216 	 */
217 	if (issue_flags & IO_URING_F_UNLOCKED)
218 		mutex_lock(&ctx->uring_lock);
219 	lockdep_assert_held(&ctx->uring_lock);
220 }
221 
222 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
223 {
224 	/* order cqe stores with ring update */
225 	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
226 }
227 
228 static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
229 {
230 	if (wq_has_sleeper(&ctx->poll_wq))
231 		__wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
232 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
233 }
234 
235 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
236 {
237 	/*
238 	 * Trigger waitqueue handler on all waiters on our waitqueue. This
239 	 * won't necessarily wake up all the tasks, io_should_wake() will make
240 	 * that decision.
241 	 *
242 	 * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
243 	 * set in the mask so that if we recurse back into our own poll
244 	 * waitqueue handlers, we know we have a dependency between eventfd or
245 	 * epoll and should terminate multishot poll at that point.
246 	 */
247 	if (wq_has_sleeper(&ctx->cq_wait))
248 		__wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
249 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
250 }
251 
252 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
253 {
254 	struct io_rings *r = ctx->rings;
255 
256 	return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
257 }
258 
259 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
260 {
261 	struct io_rings *rings = ctx->rings;
262 	unsigned int entries;
263 
264 	/* make sure SQ entry isn't read before tail */
265 	entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
266 	return min(entries, ctx->sq_entries);
267 }
268 
269 static inline int io_run_task_work(void)
270 {
271 	/*
272 	 * Always check-and-clear the task_work notification signal. With how
273 	 * signaling works for task_work, we can find it set with nothing to
274 	 * run. We need to clear it for that case, like get_signal() does.
275 	 */
276 	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
277 		clear_notify_signal();
278 	/*
279 	 * PF_IO_WORKER never returns to userspace, so check here if we have
280 	 * notify work that needs processing.
281 	 */
282 	if (current->flags & PF_IO_WORKER &&
283 	    test_thread_flag(TIF_NOTIFY_RESUME)) {
284 		__set_current_state(TASK_RUNNING);
285 		resume_user_mode_work(NULL);
286 	}
287 	if (task_work_pending(current)) {
288 		__set_current_state(TASK_RUNNING);
289 		task_work_run();
290 		return 1;
291 	}
292 
293 	return 0;
294 }
295 
296 static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
297 {
298 	return task_work_pending(current) || !wq_list_empty(&ctx->work_llist);
299 }
300 
301 static inline void io_tw_lock(struct io_ring_ctx *ctx, struct io_tw_state *ts)
302 {
303 	if (!ts->locked) {
304 		mutex_lock(&ctx->uring_lock);
305 		ts->locked = true;
306 	}
307 }
308 
309 /*
310  * Don't complete immediately but use deferred completion infrastructure.
311  * Protected by ->uring_lock and can only be used either with
312  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
313  */
314 static inline void io_req_complete_defer(struct io_kiocb *req)
315 	__must_hold(&req->ctx->uring_lock)
316 {
317 	struct io_submit_state *state = &req->ctx->submit_state;
318 
319 	lockdep_assert_held(&req->ctx->uring_lock);
320 
321 	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
322 }
323 
324 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
325 {
326 	if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
327 		     ctx->has_evfd || ctx->poll_activated))
328 		__io_commit_cqring_flush(ctx);
329 }
330 
331 static inline void io_get_task_refs(int nr)
332 {
333 	struct io_uring_task *tctx = current->io_uring;
334 
335 	tctx->cached_refs -= nr;
336 	if (unlikely(tctx->cached_refs < 0))
337 		io_task_refs_refill(tctx);
338 }
339 
340 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
341 {
342 	return !ctx->submit_state.free_list.next;
343 }
344 
345 extern struct kmem_cache *req_cachep;
346 
347 static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
348 {
349 	struct io_kiocb *req;
350 
351 	req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
352 	wq_stack_extract(&ctx->submit_state.free_list);
353 	return req;
354 }
355 
356 static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
357 {
358 	if (unlikely(io_req_cache_empty(ctx))) {
359 		if (!__io_alloc_req_refill(ctx))
360 			return false;
361 	}
362 	*req = io_extract_req(ctx);
363 	return true;
364 }
365 
366 static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
367 {
368 	return likely(ctx->submitter_task == current);
369 }
370 
371 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
372 {
373 	return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
374 		      ctx->submitter_task == current);
375 }
376 
377 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
378 {
379 	io_req_set_res(req, res, 0);
380 	req->io_task_work.func = io_req_task_complete;
381 	io_req_task_work_add(req);
382 }
383 
384 /*
385  * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
386  * slot.
387  */
388 static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
389 {
390 	if (ctx->flags & IORING_SETUP_SQE128)
391 		return 2 * sizeof(struct io_uring_sqe);
392 	return sizeof(struct io_uring_sqe);
393 }
394 #endif
395