io_uring/io_uring.h

   1 #ifndef IOU_CORE_H
   2 #define IOU_CORE_H
   3
   4 #include <linux/errno.h>
   5 #include <linux/lockdep.h>
   6 #include <linux/io_uring_types.h>
   7 #include <uapi/linux/eventpoll.h>
   8 #include "io-wq.h"
   9 #include "slist.h"
  10 #include "filetable.h"
  11
  12 #ifndef CREATE_TRACE_POINTS
  13 #include <trace/events/io_uring.h>
  14 #endif
  15
  16 enum {
  17         IOU_OK                  = 0,
  18         IOU_ISSUE_SKIP_COMPLETE = -EIOCBQUEUED,
  19
  20         /*
  21          * Intended only when both IO_URING_F_MULTISHOT is passed
  22          * to indicate to the poll runner that multishot should be
  23          * removed and the result is set on req->cqe.res.
  24          */
  25         IOU_STOP_MULTISHOT      = -ECANCELED,
  26 };
  27
  28 struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow);
  29 bool io_req_cqe_overflow(struct io_kiocb *req);
  30 int io_run_task_work_sig(struct io_ring_ctx *ctx);
  31 int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked);
  32 int io_run_local_work(struct io_ring_ctx *ctx);
  33 void io_req_defer_failed(struct io_kiocb *req, s32 res);
  34 void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags);
  35 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
  36 bool io_aux_cqe(struct io_ring_ctx *ctx, bool defer, u64 user_data, s32 res, u32 cflags,
  37                 bool allow_overflow);
  38 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
  39
  40 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
  41
  42 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
  43 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
  44                                unsigned issue_flags);
  45
  46 static inline bool io_req_ffs_set(struct io_kiocb *req)
  47 {
  48         return req->flags & REQ_F_FIXED_FILE;
  49 }
  50
  51 void __io_req_task_work_add(struct io_kiocb *req, bool allow_local);
  52 bool io_is_uring_fops(struct file *file);
  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, bool *dont_use);
  56 void io_req_task_complete(struct io_kiocb *req, bool *locked);
  57 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
  58 void io_req_task_submit(struct io_kiocb *req, bool *locked);
  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_poll_issue(struct io_kiocb *req, bool *locked);
  65 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
  66 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
  67 void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node);
  68 int io_req_prep_async(struct io_kiocb *req);
  69
  70 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
  71 void io_wq_submit_work(struct io_wq_work *work);
  72
  73 void io_free_req(struct io_kiocb *req);
  74 void io_queue_next(struct io_kiocb *req);
  75 void __io_put_task(struct task_struct *task, int nr);
  76 void io_task_refs_refill(struct io_uring_task *tctx);
  77 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
  78
  79 bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
  80                         bool cancel_all);
  81
  82 #define io_lockdep_assert_cq_locked(ctx)                                \
  83         do {                                                            \
  84                 if (ctx->flags & IORING_SETUP_IOPOLL) {                 \
  85                         lockdep_assert_held(&ctx->uring_lock);          \
  86                 } else if (!ctx->task_complete) {                       \
  87                         lockdep_assert_held(&ctx->completion_lock);     \
  88                 } else if (ctx->submitter_task->flags & PF_EXITING) {   \
  89                         lockdep_assert(current_work());                 \
  90                 } else {                                                \
  91                         lockdep_assert(current == ctx->submitter_task); \
  92                 }                                                       \
  93         } while (0)
  94
  95 static inline void io_req_task_work_add(struct io_kiocb *req)
  96 {
  97         __io_req_task_work_add(req, true);
  98 }
  99
 100 #define io_for_each_link(pos, head) \
 101         for (pos = (head); pos; pos = pos->link)
 102
 103 void io_cq_unlock_post(struct io_ring_ctx *ctx);
 104
 105 static inline struct io_uring_cqe *io_get_cqe_overflow(struct io_ring_ctx *ctx,
 106                                                        bool overflow)
 107 {
 108         io_lockdep_assert_cq_locked(ctx);
 109
 110         if (likely(ctx->cqe_cached < ctx->cqe_sentinel)) {
 111                 struct io_uring_cqe *cqe = ctx->cqe_cached;
 112
 113                 ctx->cached_cq_tail++;
 114                 ctx->cqe_cached++;
 115                 if (ctx->flags & IORING_SETUP_CQE32)
 116                         ctx->cqe_cached++;
 117                 return cqe;
 118         }
 119
 120         return __io_get_cqe(ctx, overflow);
 121 }
 122
 123 static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx)
 124 {
 125         return io_get_cqe_overflow(ctx, false);
 126 }
 127
 128 static inline bool __io_fill_cqe_req(struct io_ring_ctx *ctx,
 129                                      struct io_kiocb *req)
 130 {
 131         struct io_uring_cqe *cqe;
 132
 133         /*
 134          * If we can't get a cq entry, userspace overflowed the
 135          * submission (by quite a lot). Increment the overflow count in
 136          * the ring.
 137          */
 138         cqe = io_get_cqe(ctx);
 139         if (unlikely(!cqe))
 140                 return false;
 141
 142         trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
 143                                 req->cqe.res, req->cqe.flags,
 144                                 (req->flags & REQ_F_CQE32_INIT) ? req->extra1 : 0,
 145                                 (req->flags & REQ_F_CQE32_INIT) ? req->extra2 : 0);
 146
 147         memcpy(cqe, &req->cqe, sizeof(*cqe));
 148
 149         if (ctx->flags & IORING_SETUP_CQE32) {
 150                 u64 extra1 = 0, extra2 = 0;
 151
 152                 if (req->flags & REQ_F_CQE32_INIT) {
 153                         extra1 = req->extra1;
 154                         extra2 = req->extra2;
 155                 }
 156
 157                 WRITE_ONCE(cqe->big_cqe[0], extra1);
 158                 WRITE_ONCE(cqe->big_cqe[1], extra2);
 159         }
 160         return true;
 161 }
 162
 163 static inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
 164                                    struct io_kiocb *req)
 165 {
 166         if (likely(__io_fill_cqe_req(ctx, req)))
 167                 return true;
 168         return io_req_cqe_overflow(req);
 169 }
 170
 171 static inline void req_set_fail(struct io_kiocb *req)
 172 {
 173         req->flags |= REQ_F_FAIL;
 174         if (req->flags & REQ_F_CQE_SKIP) {
 175                 req->flags &= ~REQ_F_CQE_SKIP;
 176                 req->flags |= REQ_F_SKIP_LINK_CQES;
 177         }
 178 }
 179
 180 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
 181 {
 182         req->cqe.res = res;
 183         req->cqe.flags = cflags;
 184 }
 185
 186 static inline bool req_has_async_data(struct io_kiocb *req)
 187 {
 188         return req->flags & REQ_F_ASYNC_DATA;
 189 }
 190
 191 static inline void io_put_file(struct file *file)
 192 {
 193         if (file)
 194                 fput(file);
 195 }
 196
 197 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
 198                                          unsigned issue_flags)
 199 {
 200         lockdep_assert_held(&ctx->uring_lock);
 201         if (issue_flags & IO_URING_F_UNLOCKED)
 202                 mutex_unlock(&ctx->uring_lock);
 203 }
 204
 205 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
 206                                        unsigned issue_flags)
 207 {
 208         /*
 209          * "Normal" inline submissions always hold the uring_lock, since we
 210          * grab it from the system call. Same is true for the SQPOLL offload.
 211          * The only exception is when we've detached the request and issue it
 212          * from an async worker thread, grab the lock for that case.
 213          */
 214         if (issue_flags & IO_URING_F_UNLOCKED)
 215                 mutex_lock(&ctx->uring_lock);
 216         lockdep_assert_held(&ctx->uring_lock);
 217 }
 218
 219 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
 220 {
 221         /* order cqe stores with ring update */
 222         smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
 223 }
 224
 225 /* requires smb_mb() prior, see wq_has_sleeper() */
 226 static inline void __io_cqring_wake(struct io_ring_ctx *ctx)
 227 {
 228         /*
 229          * Trigger waitqueue handler on all waiters on our waitqueue. This
 230          * won't necessarily wake up all the tasks, io_should_wake() will make
 231          * that decision.
 232          *
 233          * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
 234          * set in the mask so that if we recurse back into our own poll
 235          * waitqueue handlers, we know we have a dependency between eventfd or
 236          * epoll and should terminate multishot poll at that point.
 237          */
 238         if (waitqueue_active(&ctx->cq_wait))
 239                 __wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
 240                                 poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 241 }
 242
 243 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
 244 {
 245         smp_mb();
 246         __io_cqring_wake(ctx);
 247 }
 248
 249 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
 250 {
 251         struct io_rings *r = ctx->rings;
 252
 253         return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
 254 }
 255
 256 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
 257 {
 258         struct io_rings *rings = ctx->rings;
 259
 260         /* make sure SQ entry isn't read before tail */
 261         return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
 262 }
 263
 264 static inline int io_run_task_work(void)
 265 {
 266         /*
 267          * Always check-and-clear the task_work notification signal. With how
 268          * signaling works for task_work, we can find it set with nothing to
 269          * run. We need to clear it for that case, like get_signal() does.
 270          */
 271         if (test_thread_flag(TIF_NOTIFY_SIGNAL))
 272                 clear_notify_signal();
 273         if (task_work_pending(current)) {
 274                 __set_current_state(TASK_RUNNING);
 275                 task_work_run();
 276                 return 1;
 277         }
 278
 279         return 0;
 280 }
 281
 282 static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
 283 {
 284         return task_work_pending(current) || !wq_list_empty(&ctx->work_llist);
 285 }
 286
 287 static inline int io_run_task_work_ctx(struct io_ring_ctx *ctx)
 288 {
 289         int ret = 0;
 290         int ret2;
 291
 292         if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
 293                 ret = io_run_local_work(ctx);
 294
 295         /* want to run this after in case more is added */
 296         ret2 = io_run_task_work();
 297
 298         /* Try propagate error in favour of if tasks were run,
 299          * but still make sure to run them if requested
 300          */
 301         if (ret >= 0)
 302                 ret += ret2;
 303
 304         return ret;
 305 }
 306
 307 static inline int io_run_local_work_locked(struct io_ring_ctx *ctx)
 308 {
 309         bool locked;
 310         int ret;
 311
 312         if (llist_empty(&ctx->work_llist))
 313                 return 0;
 314
 315         locked = true;
 316         ret = __io_run_local_work(ctx, &locked);
 317         /* shouldn't happen! */
 318         if (WARN_ON_ONCE(!locked))
 319                 mutex_lock(&ctx->uring_lock);
 320         return ret;
 321 }
 322
 323 static inline void io_tw_lock(struct io_ring_ctx *ctx, bool *locked)
 324 {
 325         if (!*locked) {
 326                 mutex_lock(&ctx->uring_lock);
 327                 *locked = true;
 328         }
 329 }
 330
 331 /*
 332  * Don't complete immediately but use deferred completion infrastructure.
 333  * Protected by ->uring_lock and can only be used either with
 334  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
 335  */
 336 static inline void io_req_complete_defer(struct io_kiocb *req)
 337         __must_hold(&req->ctx->uring_lock)
 338 {
 339         struct io_submit_state *state = &req->ctx->submit_state;
 340
 341         lockdep_assert_held(&req->ctx->uring_lock);
 342
 343         wq_list_add_tail(&req->comp_list, &state->compl_reqs);
 344 }
 345
 346 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
 347 {
 348         if (unlikely(ctx->off_timeout_used || ctx->drain_active || ctx->has_evfd))
 349                 __io_commit_cqring_flush(ctx);
 350 }
 351
 352 /* must to be called somewhat shortly after putting a request */
 353 static inline void io_put_task(struct task_struct *task, int nr)
 354 {
 355         if (likely(task == current))
 356                 task->io_uring->cached_refs += nr;
 357         else
 358                 __io_put_task(task, nr);
 359 }
 360
 361 static inline void io_get_task_refs(int nr)
 362 {
 363         struct io_uring_task *tctx = current->io_uring;
 364
 365         tctx->cached_refs -= nr;
 366         if (unlikely(tctx->cached_refs < 0))
 367                 io_task_refs_refill(tctx);
 368 }
 369
 370 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
 371 {
 372         return !ctx->submit_state.free_list.next;
 373 }
 374
 375 static inline bool io_alloc_req_refill(struct io_ring_ctx *ctx)
 376 {
 377         if (unlikely(io_req_cache_empty(ctx)))
 378                 return __io_alloc_req_refill(ctx);
 379         return true;
 380 }
 381
 382 static inline struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
 383 {
 384         struct io_wq_work_node *node;
 385
 386         node = wq_stack_extract(&ctx->submit_state.free_list);
 387         return container_of(node, struct io_kiocb, comp_list);
 388 }
 389
 390 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
 391 {
 392         return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
 393                       ctx->submitter_task == current);
 394 }
 395
 396 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
 397 {
 398         io_req_set_res(req, res, 0);
 399         req->io_task_work.func = io_req_task_complete;
 400         io_req_task_work_add(req);
 401 }
 402
 403 #endif