xref: /linux/io_uring/io_uring.h (revision 0bef512012b1cd8820f0c9ec80e5f8ceb43fdd59) 
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 	IOU_OK			= 0,
20 	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,
21 
22 	/*
23 	 * Requeue the task_work to restart operations on this request. The
24 	 * actual value isn't important, should just be not an otherwise
25 	 * valid error code, yet less than -MAX_ERRNO and valid internally.
26 	 */
27 	IOU_REQUEUE		= -3072,
28 
29 	/*
30 	 * Intended only when both IO_URING_F_MULTISHOT is passed
31 	 * to indicate to the poll runner that multishot should be
32 	 * removed and the result is set on req->cqe.res.
33 	 */
34 	IOU_STOP_MULTISHOT	= -ECANCELED,
35 };
36 
37 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
38 void io_req_cqe_overflow(struct io_kiocb *req);
39 int io_run_task_work_sig(struct io_ring_ctx *ctx);
40 void io_req_defer_failed(struct io_kiocb *req, s32 res);
41 void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags);
42 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
43 bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags);
44 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
45 
46 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
47 
48 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
49 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
50 			       unsigned issue_flags);
51 
52 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
53 bool io_alloc_async_data(struct io_kiocb *req);
54 void io_req_task_queue(struct io_kiocb *req);
55 void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use);
56 void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
57 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
58 void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
59 void tctx_task_work(struct callback_head *cb);
60 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
61 int io_uring_alloc_task_context(struct task_struct *task,
62 				struct io_ring_ctx *ctx);
63 
64 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
65 				     int start, int end);
66 
67 int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts);
68 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
69 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
70 void __io_submit_flush_completions(struct io_ring_ctx *ctx);
71 int io_req_prep_async(struct io_kiocb *req);
72 
73 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
74 void io_wq_submit_work(struct io_wq_work *work);
75 
76 void io_free_req(struct io_kiocb *req);
77 void io_queue_next(struct io_kiocb *req);
78 void io_task_refs_refill(struct io_uring_task *tctx);
79 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
80 
81 bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
82 			bool cancel_all);
83 
84 void *io_mem_alloc(size_t size);
85 void io_mem_free(void *ptr);
86 
87 enum {
88 	IO_EVENTFD_OP_SIGNAL_BIT,
89 	IO_EVENTFD_OP_FREE_BIT,
90 };
91 
92 void io_eventfd_ops(struct rcu_head *rcu);
93 void io_activate_pollwq(struct io_ring_ctx *ctx);
94 
95 #if defined(CONFIG_PROVE_LOCKING)
96 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
97 {
98 	lockdep_assert(in_task());
99 
100 	if (ctx->flags & IORING_SETUP_IOPOLL) {
101 		lockdep_assert_held(&ctx->uring_lock);
102 	} else if (!ctx->task_complete) {
103 		lockdep_assert_held(&ctx->completion_lock);
104 	} else if (ctx->submitter_task) {
105 		/*
106 		 * ->submitter_task may be NULL and we can still post a CQE,
107 		 * if the ring has been setup with IORING_SETUP_R_DISABLED.
108 		 * Not from an SQE, as those cannot be submitted, but via
109 		 * updating tagged resources.
110 		 */
111 		if (ctx->submitter_task->flags & PF_EXITING)
112 			lockdep_assert(current_work());
113 		else
114 			lockdep_assert(current == ctx->submitter_task);
115 	}
116 }
117 #else
118 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
119 {
120 }
121 #endif
122 
123 static inline void io_req_task_work_add(struct io_kiocb *req)
124 {
125 	__io_req_task_work_add(req, 0);
126 }
127 
128 #define io_for_each_link(pos, head) \
129 	for (pos = (head); pos; pos = pos->link)
130 
131 static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
132 					struct io_uring_cqe **ret,
133 					bool overflow)
134 {
135 	io_lockdep_assert_cq_locked(ctx);
136 
137 	if (unlikely(ctx->cqe_cached >= ctx->cqe_sentinel)) {
138 		if (unlikely(!io_cqe_cache_refill(ctx, overflow)))
139 			return false;
140 	}
141 	*ret = ctx->cqe_cached;
142 	ctx->cached_cq_tail++;
143 	ctx->cqe_cached++;
144 	if (ctx->flags & IORING_SETUP_CQE32)
145 		ctx->cqe_cached++;
146 	return true;
147 }
148 
149 static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret)
150 {
151 	return io_get_cqe_overflow(ctx, ret, false);
152 }
153 
154 static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
155 					    struct io_kiocb *req)
156 {
157 	struct io_uring_cqe *cqe;
158 
159 	/*
160 	 * If we can't get a cq entry, userspace overflowed the
161 	 * submission (by quite a lot). Increment the overflow count in
162 	 * the ring.
163 	 */
164 	if (unlikely(!io_get_cqe(ctx, &cqe)))
165 		return false;
166 
167 	if (trace_io_uring_complete_enabled())
168 		trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
169 					req->cqe.res, req->cqe.flags,
170 					req->big_cqe.extra1, req->big_cqe.extra2);
171 
172 	memcpy(cqe, &req->cqe, sizeof(*cqe));
173 	if (ctx->flags & IORING_SETUP_CQE32) {
174 		memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
175 		memset(&req->big_cqe, 0, sizeof(req->big_cqe));
176 	}
177 	return true;
178 }
179 
180 static inline void req_set_fail(struct io_kiocb *req)
181 {
182 	req->flags |= REQ_F_FAIL;
183 	if (req->flags & REQ_F_CQE_SKIP) {
184 		req->flags &= ~REQ_F_CQE_SKIP;
185 		req->flags |= REQ_F_SKIP_LINK_CQES;
186 	}
187 }
188 
189 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
190 {
191 	req->cqe.res = res;
192 	req->cqe.flags = cflags;
193 }
194 
195 static inline bool req_has_async_data(struct io_kiocb *req)
196 {
197 	return req->flags & REQ_F_ASYNC_DATA;
198 }
199 
200 static inline void io_put_file(struct io_kiocb *req)
201 {
202 	if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
203 		fput(req->file);
204 }
205 
206 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
207 					 unsigned issue_flags)
208 {
209 	lockdep_assert_held(&ctx->uring_lock);
210 	if (issue_flags & IO_URING_F_UNLOCKED)
211 		mutex_unlock(&ctx->uring_lock);
212 }
213 
214 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
215 				       unsigned issue_flags)
216 {
217 	/*
218 	 * "Normal" inline submissions always hold the uring_lock, since we
219 	 * grab it from the system call. Same is true for the SQPOLL offload.
220 	 * The only exception is when we've detached the request and issue it
221 	 * from an async worker thread, grab the lock for that case.
222 	 */
223 	if (issue_flags & IO_URING_F_UNLOCKED)
224 		mutex_lock(&ctx->uring_lock);
225 	lockdep_assert_held(&ctx->uring_lock);
226 }
227 
228 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
229 {
230 	/* order cqe stores with ring update */
231 	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
232 }
233 
234 static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
235 {
236 	if (wq_has_sleeper(&ctx->poll_wq))
237 		__wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
238 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
239 }
240 
241 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
242 {
243 	/*
244 	 * Trigger waitqueue handler on all waiters on our waitqueue. This
245 	 * won't necessarily wake up all the tasks, io_should_wake() will make
246 	 * that decision.
247 	 *
248 	 * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
249 	 * set in the mask so that if we recurse back into our own poll
250 	 * waitqueue handlers, we know we have a dependency between eventfd or
251 	 * epoll and should terminate multishot poll at that point.
252 	 */
253 	if (wq_has_sleeper(&ctx->cq_wait))
254 		__wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
255 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
256 }
257 
258 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
259 {
260 	struct io_rings *r = ctx->rings;
261 
262 	return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
263 }
264 
265 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
266 {
267 	struct io_rings *rings = ctx->rings;
268 	unsigned int entries;
269 
270 	/* make sure SQ entry isn't read before tail */
271 	entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
272 	return min(entries, ctx->sq_entries);
273 }
274 
275 static inline int io_run_task_work(void)
276 {
277 	/*
278 	 * Always check-and-clear the task_work notification signal. With how
279 	 * signaling works for task_work, we can find it set with nothing to
280 	 * run. We need to clear it for that case, like get_signal() does.
281 	 */
282 	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
283 		clear_notify_signal();
284 	/*
285 	 * PF_IO_WORKER never returns to userspace, so check here if we have
286 	 * notify work that needs processing.
287 	 */
288 	if (current->flags & PF_IO_WORKER &&
289 	    test_thread_flag(TIF_NOTIFY_RESUME)) {
290 		__set_current_state(TASK_RUNNING);
291 		resume_user_mode_work(NULL);
292 	}
293 	if (task_work_pending(current)) {
294 		__set_current_state(TASK_RUNNING);
295 		task_work_run();
296 		return 1;
297 	}
298 
299 	return 0;
300 }
301 
302 static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
303 {
304 	return task_work_pending(current) || !wq_list_empty(&ctx->work_llist);
305 }
306 
307 static inline void io_tw_lock(struct io_ring_ctx *ctx, struct io_tw_state *ts)
308 {
309 	if (!ts->locked) {
310 		mutex_lock(&ctx->uring_lock);
311 		ts->locked = true;
312 	}
313 }
314 
315 /*
316  * Don't complete immediately but use deferred completion infrastructure.
317  * Protected by ->uring_lock and can only be used either with
318  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
319  */
320 static inline void io_req_complete_defer(struct io_kiocb *req)
321 	__must_hold(&req->ctx->uring_lock)
322 {
323 	struct io_submit_state *state = &req->ctx->submit_state;
324 
325 	lockdep_assert_held(&req->ctx->uring_lock);
326 
327 	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
328 }
329 
330 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
331 {
332 	if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
333 		     ctx->has_evfd || ctx->poll_activated))
334 		__io_commit_cqring_flush(ctx);
335 }
336 
337 static inline void io_get_task_refs(int nr)
338 {
339 	struct io_uring_task *tctx = current->io_uring;
340 
341 	tctx->cached_refs -= nr;
342 	if (unlikely(tctx->cached_refs < 0))
343 		io_task_refs_refill(tctx);
344 }
345 
346 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
347 {
348 	return !ctx->submit_state.free_list.next;
349 }
350 
351 extern struct kmem_cache *req_cachep;
352 extern struct kmem_cache *io_buf_cachep;
353 
354 static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
355 {
356 	struct io_kiocb *req;
357 
358 	req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
359 	wq_stack_extract(&ctx->submit_state.free_list);
360 	return req;
361 }
362 
363 static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
364 {
365 	if (unlikely(io_req_cache_empty(ctx))) {
366 		if (!__io_alloc_req_refill(ctx))
367 			return false;
368 	}
369 	*req = io_extract_req(ctx);
370 	return true;
371 }
372 
373 static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
374 {
375 	return likely(ctx->submitter_task == current);
376 }
377 
378 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
379 {
380 	return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
381 		      ctx->submitter_task == current);
382 }
383 
384 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
385 {
386 	io_req_set_res(req, res, 0);
387 	req->io_task_work.func = io_req_task_complete;
388 	io_req_task_work_add(req);
389 }
390 
391 /*
392  * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
393  * slot.
394  */
395 static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
396 {
397 	if (ctx->flags & IORING_SETUP_SQE128)
398 		return 2 * sizeof(struct io_uring_sqe);
399 	return sizeof(struct io_uring_sqe);
400 }
401 #endif
402