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
18enum {
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
29enum {
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
41bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
42void io_req_cqe_overflow(struct io_kiocb *req);
43int io_run_task_work_sig(struct io_ring_ctx *ctx);
44void io_req_defer_failed(struct io_kiocb *req, s32 res);
45void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags);
46bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
47bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags);
48void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
49
50struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
51
52struct file *io_file_get_normal(struct io_kiocb *req, int fd);
53struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
54 unsigned issue_flags);
55
56void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
57bool io_is_uring_fops(struct file *file);
58bool io_alloc_async_data(struct io_kiocb *req);
59void io_req_task_queue(struct io_kiocb *req);
60void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use);
61void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
62void io_req_task_queue_fail(struct io_kiocb *req, int ret);
63void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
64void tctx_task_work(struct callback_head *cb);
65__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
66int io_uring_alloc_task_context(struct task_struct *task,
67 struct io_ring_ctx *ctx);
68
69int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
70 int start, int end);
71
72int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts);
73int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
74int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
75void __io_submit_flush_completions(struct io_ring_ctx *ctx);
76int io_req_prep_async(struct io_kiocb *req);
77
78struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
79void io_wq_submit_work(struct io_wq_work *work);
80
81void io_free_req(struct io_kiocb *req);
82void io_queue_next(struct io_kiocb *req);
83void io_task_refs_refill(struct io_uring_task *tctx);
84bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
85
86bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
87 bool cancel_all);
88
89#if defined(CONFIG_PROVE_LOCKING)
90static 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
112static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
113{
114}
115#endif
116
117static inline void io_req_task_work_add(struct io_kiocb *req)
118{
119 __io_req_task_work_add(req, flags: 0);
120}
121
122#define io_for_each_link(pos, head) \
123 for (pos = (head); pos; pos = pos->link)
124
125static 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
143static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret)
144{
145 return io_get_cqe_overflow(ctx, ret, overflow: false);
146}
147
148static __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(ctx: req->ctx, req, user_data: req->cqe.user_data,
163 res: req->cqe.res, cflags: req->cqe.flags,
164 extra1: req->big_cqe.extra1, extra2: 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
174static 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
183static 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
189static inline bool req_has_async_data(struct io_kiocb *req)
190{
191 return req->flags & REQ_F_ASYNC_DATA;
192}
193
194static 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
200static 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(lock: &ctx->uring_lock);
206}
207
208static 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
222static 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
228static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
229{
230 if (wq_has_sleeper(wq_head: &ctx->poll_wq))
231 __wake_up(wq_head: &ctx->poll_wq, TASK_NORMAL, nr: 0,
232 poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
233}
234
235static 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(wq_head: &ctx->cq_wait))
248 __wake_up(wq_head: &ctx->cq_wait, TASK_NORMAL, nr: 0,
249 poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
250}
251
252static 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
259static 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
269static 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
296static 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
301static 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 */
314static 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(node: &req->comp_list, list: &state->compl_reqs);
322}
323
324static 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
331static 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
340static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
341{
342 return !ctx->submit_state.free_list.next;
343}
344
345extern struct kmem_cache *req_cachep;
346extern struct kmem_cache *io_buf_cachep;
347
348static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
349{
350 struct io_kiocb *req;
351
352 req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
353 wq_stack_extract(stack: &ctx->submit_state.free_list);
354 return req;
355}
356
357static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
358{
359 if (unlikely(io_req_cache_empty(ctx))) {
360 if (!__io_alloc_req_refill(ctx))
361 return false;
362 }
363 *req = io_extract_req(ctx);
364 return true;
365}
366
367static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
368{
369 return likely(ctx->submitter_task == current);
370}
371
372static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
373{
374 return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
375 ctx->submitter_task == current);
376}
377
378static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
379{
380 io_req_set_res(req, res, cflags: 0);
381 req->io_task_work.func = io_req_task_complete;
382 io_req_task_work_add(req);
383}
384
385/*
386 * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
387 * slot.
388 */
389static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
390{
391 if (ctx->flags & IORING_SETUP_SQE128)
392 return 2 * sizeof(struct io_uring_sqe);
393 return sizeof(struct io_uring_sqe);
394}
395#endif
396

source code of linux/io_uring/io_uring.h