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/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 "io-wq.h"
  12 #include "slist.h"
  13 #include "filetable.h"
  14
  15 #ifndef CREATE_TRACE_POINTS
  16 #include <trace/events/io_uring.h>
  17 #endif
  18
  19 enum {
  20         IOU_OK                  = 0,
  21         IOU_ISSUE_SKIP_COMPLETE = -EIOCBQUEUED,
  22
  23         /*
  24          * Requeue the task_work to restart operations on this request. The
  25          * actual value isn't important, should just be not an otherwise
  26          * valid error code, yet less than -MAX_ERRNO and valid internally.
  27          */
  28         IOU_REQUEUE             = -3072,
  29
  30         /*
  31          * Intended only when both IO_URING_F_MULTISHOT is passed
  32          * to indicate to the poll runner that multishot should be
  33          * removed and the result is set on req->cqe.res.
  34          */
  35         IOU_STOP_MULTISHOT      = -ECANCELED,
  36 };
  37
  38 struct io_wait_queue {
  39         struct wait_queue_entry wq;
  40         struct io_ring_ctx *ctx;
  41         unsigned cq_tail;
  42         unsigned cq_min_tail;
  43         unsigned nr_timeouts;
  44         int hit_timeout;
  45         ktime_t min_timeout;
  46         ktime_t timeout;
  47         struct hrtimer t;
  48
  49 #ifdef CONFIG_NET_RX_BUSY_POLL
  50         ktime_t napi_busy_poll_dt;
  51         bool napi_prefer_busy_poll;
  52 #endif
  53 };
  54
  55 static inline bool io_should_wake(struct io_wait_queue *iowq)
  56 {
  57         struct io_ring_ctx *ctx = iowq->ctx;
  58         int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
  59
  60         /*
  61          * Wake up if we have enough events, or if a timeout occurred since we
  62          * started waiting. For timeouts, we always want to return to userspace,
  63          * regardless of event count.
  64          */
  65         return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
  66 }
  67
  68 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
  69 int io_run_task_work_sig(struct io_ring_ctx *ctx);
  70 void io_req_defer_failed(struct io_kiocb *req, s32 res);
  71 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
  72 void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
  73 bool io_req_post_cqe(struct io_kiocb *req, s32 res, u32 cflags);
  74 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
  75
  76 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
  77 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
  78                                unsigned issue_flags);
  79
  80 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
  81 void io_req_task_work_add_remote(struct io_kiocb *req, struct io_ring_ctx *ctx,
  82                                  unsigned flags);
  83 bool io_alloc_async_data(struct io_kiocb *req);
  84 void io_req_task_queue(struct io_kiocb *req);
  85 void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
  86 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
  87 void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
  88 struct llist_node *io_handle_tw_list(struct llist_node *node, unsigned int *count, unsigned int max_entries);
  89 struct llist_node *tctx_task_work_run(struct io_uring_task *tctx, unsigned int max_entries, unsigned int *count);
  90 void tctx_task_work(struct callback_head *cb);
  91 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
  92 int io_uring_alloc_task_context(struct task_struct *task,
  93                                 struct io_ring_ctx *ctx);
  94
  95 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
  96                                      int start, int end);
  97 void io_req_queue_iowq(struct io_kiocb *req);
  98
  99 int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts);
 100 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
 101 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
 102 void __io_submit_flush_completions(struct io_ring_ctx *ctx);
 103
 104 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
 105 void io_wq_submit_work(struct io_wq_work *work);
 106
 107 void io_free_req(struct io_kiocb *req);
 108 void io_queue_next(struct io_kiocb *req);
 109 void io_task_refs_refill(struct io_uring_task *tctx);
 110 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
 111
 112 bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
 113                         bool cancel_all);
 114
 115 void io_activate_pollwq(struct io_ring_ctx *ctx);
 116
 117 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
 118 {
 119 #if defined(CONFIG_PROVE_LOCKING)
 120         lockdep_assert(in_task());
 121
 122         if (ctx->flags & IORING_SETUP_IOPOLL) {
 123                 lockdep_assert_held(&ctx->uring_lock);
 124         } else if (!ctx->task_complete) {
 125                 lockdep_assert_held(&ctx->completion_lock);
 126         } else if (ctx->submitter_task) {
 127                 /*
 128                  * ->submitter_task may be NULL and we can still post a CQE,
 129                  * if the ring has been setup with IORING_SETUP_R_DISABLED.
 130                  * Not from an SQE, as those cannot be submitted, but via
 131                  * updating tagged resources.
 132                  */
 133                 if (ctx->submitter_task->flags & PF_EXITING)
 134                         lockdep_assert(current_work());
 135                 else
 136                         lockdep_assert(current == ctx->submitter_task);
 137         }
 138 #endif
 139 }
 140
 141 static inline void io_req_task_work_add(struct io_kiocb *req)
 142 {
 143         __io_req_task_work_add(req, 0);
 144 }
 145
 146 static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
 147 {
 148         if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
 149             ctx->submit_state.cq_flush)
 150                 __io_submit_flush_completions(ctx);
 151 }
 152
 153 #define io_for_each_link(pos, head) \
 154         for (pos = (head); pos; pos = pos->link)
 155
 156 static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
 157                                         struct io_uring_cqe **ret,
 158                                         bool overflow)
 159 {
 160         io_lockdep_assert_cq_locked(ctx);
 161
 162         if (unlikely(ctx->cqe_cached >= ctx->cqe_sentinel)) {
 163                 if (unlikely(!io_cqe_cache_refill(ctx, overflow)))
 164                         return false;
 165         }
 166         *ret = ctx->cqe_cached;
 167         ctx->cached_cq_tail++;
 168         ctx->cqe_cached++;
 169         if (ctx->flags & IORING_SETUP_CQE32)
 170                 ctx->cqe_cached++;
 171         return true;
 172 }
 173
 174 static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret)
 175 {
 176         return io_get_cqe_overflow(ctx, ret, false);
 177 }
 178
 179 static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
 180                                             struct io_kiocb *req)
 181 {
 182         struct io_uring_cqe *cqe;
 183
 184         /*
 185          * If we can't get a cq entry, userspace overflowed the
 186          * submission (by quite a lot). Increment the overflow count in
 187          * the ring.
 188          */
 189         if (unlikely(!io_get_cqe(ctx, &cqe)))
 190                 return false;
 191
 192         if (trace_io_uring_complete_enabled())
 193                 trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
 194                                         req->cqe.res, req->cqe.flags,
 195                                         req->big_cqe.extra1, req->big_cqe.extra2);
 196
 197         memcpy(cqe, &req->cqe, sizeof(*cqe));
 198         if (ctx->flags & IORING_SETUP_CQE32) {
 199                 memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
 200                 memset(&req->big_cqe, 0, sizeof(req->big_cqe));
 201         }
 202         return true;
 203 }
 204
 205 static inline void req_set_fail(struct io_kiocb *req)
 206 {
 207         req->flags |= REQ_F_FAIL;
 208         if (req->flags & REQ_F_CQE_SKIP) {
 209                 req->flags &= ~REQ_F_CQE_SKIP;
 210                 req->flags |= REQ_F_SKIP_LINK_CQES;
 211         }
 212 }
 213
 214 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
 215 {
 216         req->cqe.res = res;
 217         req->cqe.flags = cflags;
 218 }
 219
 220 static inline bool req_has_async_data(struct io_kiocb *req)
 221 {
 222         return req->flags & REQ_F_ASYNC_DATA;
 223 }
 224
 225 static inline void io_put_file(struct io_kiocb *req)
 226 {
 227         if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
 228                 fput(req->file);
 229 }
 230
 231 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
 232                                          unsigned issue_flags)
 233 {
 234         lockdep_assert_held(&ctx->uring_lock);
 235         if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
 236                 mutex_unlock(&ctx->uring_lock);
 237 }
 238
 239 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
 240                                        unsigned issue_flags)
 241 {
 242         /*
 243          * "Normal" inline submissions always hold the uring_lock, since we
 244          * grab it from the system call. Same is true for the SQPOLL offload.
 245          * The only exception is when we've detached the request and issue it
 246          * from an async worker thread, grab the lock for that case.
 247          */
 248         if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
 249                 mutex_lock(&ctx->uring_lock);
 250         lockdep_assert_held(&ctx->uring_lock);
 251 }
 252
 253 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
 254 {
 255         /* order cqe stores with ring update */
 256         smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
 257 }
 258
 259 static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
 260 {
 261         if (wq_has_sleeper(&ctx->poll_wq))
 262                 __wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
 263                                 poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 264 }
 265
 266 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
 267 {
 268         /*
 269          * Trigger waitqueue handler on all waiters on our waitqueue. This
 270          * won't necessarily wake up all the tasks, io_should_wake() will make
 271          * that decision.
 272          *
 273          * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
 274          * set in the mask so that if we recurse back into our own poll
 275          * waitqueue handlers, we know we have a dependency between eventfd or
 276          * epoll and should terminate multishot poll at that point.
 277          */
 278         if (wq_has_sleeper(&ctx->cq_wait))
 279                 __wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
 280                                 poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 281 }
 282
 283 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
 284 {
 285         struct io_rings *r = ctx->rings;
 286
 287         return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
 288 }
 289
 290 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
 291 {
 292         struct io_rings *rings = ctx->rings;
 293         unsigned int entries;
 294
 295         /* make sure SQ entry isn't read before tail */
 296         entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
 297         return min(entries, ctx->sq_entries);
 298 }
 299
 300 static inline int io_run_task_work(void)
 301 {
 302         bool ret = false;
 303
 304         /*
 305          * Always check-and-clear the task_work notification signal. With how
 306          * signaling works for task_work, we can find it set with nothing to
 307          * run. We need to clear it for that case, like get_signal() does.
 308          */
 309         if (test_thread_flag(TIF_NOTIFY_SIGNAL))
 310                 clear_notify_signal();
 311         /*
 312          * PF_IO_WORKER never returns to userspace, so check here if we have
 313          * notify work that needs processing.
 314          */
 315         if (current->flags & PF_IO_WORKER) {
 316                 if (test_thread_flag(TIF_NOTIFY_RESUME)) {
 317                         __set_current_state(TASK_RUNNING);
 318                         resume_user_mode_work(NULL);
 319                 }
 320                 if (current->io_uring) {
 321                         unsigned int count = 0;
 322
 323                         tctx_task_work_run(current->io_uring, UINT_MAX, &count);
 324                         if (count)
 325                                 ret = true;
 326                 }
 327         }
 328         if (task_work_pending(current)) {
 329                 __set_current_state(TASK_RUNNING);
 330                 task_work_run();
 331                 ret = true;
 332         }
 333
 334         return ret;
 335 }
 336
 337 static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
 338 {
 339         return task_work_pending(current) || !llist_empty(&ctx->work_llist);
 340 }
 341
 342 static inline void io_tw_lock(struct io_ring_ctx *ctx, struct io_tw_state *ts)
 343 {
 344         lockdep_assert_held(&ctx->uring_lock);
 345 }
 346
 347 /*
 348  * Don't complete immediately but use deferred completion infrastructure.
 349  * Protected by ->uring_lock and can only be used either with
 350  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
 351  */
 352 static inline void io_req_complete_defer(struct io_kiocb *req)
 353         __must_hold(&req->ctx->uring_lock)
 354 {
 355         struct io_submit_state *state = &req->ctx->submit_state;
 356
 357         lockdep_assert_held(&req->ctx->uring_lock);
 358
 359         wq_list_add_tail(&req->comp_list, &state->compl_reqs);
 360 }
 361
 362 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
 363 {
 364         if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
 365                      ctx->has_evfd || ctx->poll_activated))
 366                 __io_commit_cqring_flush(ctx);
 367 }
 368
 369 static inline void io_get_task_refs(int nr)
 370 {
 371         struct io_uring_task *tctx = current->io_uring;
 372
 373         tctx->cached_refs -= nr;
 374         if (unlikely(tctx->cached_refs < 0))
 375                 io_task_refs_refill(tctx);
 376 }
 377
 378 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
 379 {
 380         return !ctx->submit_state.free_list.next;
 381 }
 382
 383 extern struct kmem_cache *req_cachep;
 384 extern struct kmem_cache *io_buf_cachep;
 385
 386 static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
 387 {
 388         struct io_kiocb *req;
 389
 390         req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
 391         wq_stack_extract(&ctx->submit_state.free_list);
 392         return req;
 393 }
 394
 395 static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
 396 {
 397         if (unlikely(io_req_cache_empty(ctx))) {
 398                 if (!__io_alloc_req_refill(ctx))
 399                         return false;
 400         }
 401         *req = io_extract_req(ctx);
 402         return true;
 403 }
 404
 405 static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
 406 {
 407         return likely(ctx->submitter_task == current);
 408 }
 409
 410 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
 411 {
 412         return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
 413                       ctx->submitter_task == current);
 414 }
 415
 416 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
 417 {
 418         io_req_set_res(req, res, 0);
 419         req->io_task_work.func = io_req_task_complete;
 420         io_req_task_work_add(req);
 421 }
 422
 423 /*
 424  * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
 425  * slot.
 426  */
 427 static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
 428 {
 429         if (ctx->flags & IORING_SETUP_SQE128)
 430                 return 2 * sizeof(struct io_uring_sqe);
 431         return sizeof(struct io_uring_sqe);
 432 }
 433
 434 static inline bool io_file_can_poll(struct io_kiocb *req)
 435 {
 436         if (req->flags & REQ_F_CAN_POLL)
 437                 return true;
 438         if (req->file && file_can_poll(req->file)) {
 439                 req->flags |= REQ_F_CAN_POLL;
 440                 return true;
 441         }
 442         return false;
 443 }
 444
 445 static inline ktime_t io_get_time(struct io_ring_ctx *ctx)
 446 {
 447         if (ctx->clockid == CLOCK_MONOTONIC)
 448                 return ktime_get();
 449
 450         return ktime_get_with_offset(ctx->clock_offset);
 451 }
 452
 453 enum {
 454         IO_CHECK_CQ_OVERFLOW_BIT,
 455         IO_CHECK_CQ_DROPPED_BIT,
 456 };
 457
 458 static inline bool io_has_work(struct io_ring_ctx *ctx)
 459 {
 460         return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
 461                !llist_empty(&ctx->work_llist);
 462 }
 463 #endif