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 "alloc_cache.h"
  12 #include "io-wq.h"
  13 #include "slist.h"
  14 #include "filetable.h"
  15 #include "opdef.h"
  16
  17 #ifndef CREATE_TRACE_POINTS
  18 #include <trace/events/io_uring.h>
  19 #endif
  20
  21 enum {
  22         IOU_COMPLETE            = 0,
  23
  24         IOU_ISSUE_SKIP_COMPLETE = -EIOCBQUEUED,
  25
  26         /*
  27          * The request has more work to do and should be retried. io_uring will
  28          * attempt to wait on the file for eligible opcodes, but otherwise
  29          * it'll be handed to iowq for blocking execution. It works for normal
  30          * requests as well as for the multi shot mode.
  31          */
  32         IOU_RETRY               = -EAGAIN,
  33
  34         /*
  35          * Requeue the task_work to restart operations on this request. The
  36          * actual value isn't important, should just be not an otherwise
  37          * valid error code, yet less than -MAX_ERRNO and valid internally.
  38          */
  39         IOU_REQUEUE             = -3072,
  40 };
  41
  42 struct io_wait_queue {
  43         struct wait_queue_entry wq;
  44         struct io_ring_ctx *ctx;
  45         unsigned cq_tail;
  46         unsigned cq_min_tail;
  47         unsigned nr_timeouts;
  48         int hit_timeout;
  49         ktime_t min_timeout;
  50         ktime_t timeout;
  51         struct hrtimer t;
  52
  53 #ifdef CONFIG_NET_RX_BUSY_POLL
  54         ktime_t napi_busy_poll_dt;
  55         bool napi_prefer_busy_poll;
  56 #endif
  57 };
  58
  59 static inline bool io_should_wake(struct io_wait_queue *iowq)
  60 {
  61         struct io_ring_ctx *ctx = iowq->ctx;
  62         int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail;
  63
  64         /*
  65          * Wake up if we have enough events, or if a timeout occurred since we
  66          * started waiting. For timeouts, we always want to return to userspace,
  67          * regardless of event count.
  68          */
  69         return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
  70 }
  71
  72 #define IORING_MAX_ENTRIES      32768
  73 #define IORING_MAX_CQ_ENTRIES   (2 * IORING_MAX_ENTRIES)
  74
  75 unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
  76                          unsigned int cq_entries, size_t *sq_offset);
  77 int io_uring_fill_params(unsigned entries, struct io_uring_params *p);
  78 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
  79 int io_run_task_work_sig(struct io_ring_ctx *ctx);
  80 void io_req_defer_failed(struct io_kiocb *req, s32 res);
  81 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
  82 void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
  83 bool io_req_post_cqe(struct io_kiocb *req, s32 res, u32 cflags);
  84 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
  85
  86 void io_req_track_inflight(struct io_kiocb *req);
  87 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
  88 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
  89                                unsigned issue_flags);
  90
  91 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
  92 void io_req_task_work_add_remote(struct io_kiocb *req, unsigned flags);
  93 void io_req_task_queue(struct io_kiocb *req);
  94 void io_req_task_complete(struct io_kiocb *req, io_tw_token_t tw);
  95 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
  96 void io_req_task_submit(struct io_kiocb *req, io_tw_token_t tw);
  97 struct llist_node *io_handle_tw_list(struct llist_node *node, unsigned int *count, unsigned int max_entries);
  98 struct llist_node *tctx_task_work_run(struct io_uring_task *tctx, unsigned int max_entries, unsigned int *count);
  99 void tctx_task_work(struct callback_head *cb);
 100 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
 101
 102 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
 103                                      int start, int end);
 104 void io_req_queue_iowq(struct io_kiocb *req);
 105
 106 int io_poll_issue(struct io_kiocb *req, io_tw_token_t tw);
 107 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
 108 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
 109 void __io_submit_flush_completions(struct io_ring_ctx *ctx);
 110
 111 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
 112 void io_wq_submit_work(struct io_wq_work *work);
 113
 114 void io_free_req(struct io_kiocb *req);
 115 void io_queue_next(struct io_kiocb *req);
 116 void io_task_refs_refill(struct io_uring_task *tctx);
 117 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
 118
 119 bool io_match_task_safe(struct io_kiocb *head, struct io_uring_task *tctx,
 120                         bool cancel_all);
 121
 122 void io_activate_pollwq(struct io_ring_ctx *ctx);
 123
 124 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
 125 {
 126 #if defined(CONFIG_PROVE_LOCKING)
 127         lockdep_assert(in_task());
 128
 129         if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
 130                 lockdep_assert_held(&ctx->uring_lock);
 131
 132         if (ctx->flags & IORING_SETUP_IOPOLL) {
 133                 lockdep_assert_held(&ctx->uring_lock);
 134         } else if (!ctx->task_complete) {
 135                 lockdep_assert_held(&ctx->completion_lock);
 136         } else if (ctx->submitter_task) {
 137                 /*
 138                  * ->submitter_task may be NULL and we can still post a CQE,
 139                  * if the ring has been setup with IORING_SETUP_R_DISABLED.
 140                  * Not from an SQE, as those cannot be submitted, but via
 141                  * updating tagged resources.
 142                  */
 143                 if (!percpu_ref_is_dying(&ctx->refs))
 144                         lockdep_assert(current == ctx->submitter_task);
 145         }
 146 #endif
 147 }
 148
 149 static inline bool io_is_compat(struct io_ring_ctx *ctx)
 150 {
 151         return IS_ENABLED(CONFIG_COMPAT) && unlikely(ctx->compat);
 152 }
 153
 154 static inline void io_req_task_work_add(struct io_kiocb *req)
 155 {
 156         __io_req_task_work_add(req, 0);
 157 }
 158
 159 static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
 160 {
 161         if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
 162             ctx->submit_state.cq_flush)
 163                 __io_submit_flush_completions(ctx);
 164 }
 165
 166 #define io_for_each_link(pos, head) \
 167         for (pos = (head); pos; pos = pos->link)
 168
 169 static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
 170                                         struct io_uring_cqe **ret,
 171                                         bool overflow)
 172 {
 173         io_lockdep_assert_cq_locked(ctx);
 174
 175         if (unlikely(ctx->cqe_cached >= ctx->cqe_sentinel)) {
 176                 if (unlikely(!io_cqe_cache_refill(ctx, overflow)))
 177                         return false;
 178         }
 179         *ret = ctx->cqe_cached;
 180         ctx->cached_cq_tail++;
 181         ctx->cqe_cached++;
 182         if (ctx->flags & IORING_SETUP_CQE32)
 183                 ctx->cqe_cached++;
 184         return true;
 185 }
 186
 187 static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret)
 188 {
 189         return io_get_cqe_overflow(ctx, ret, false);
 190 }
 191
 192 static inline bool io_defer_get_uncommited_cqe(struct io_ring_ctx *ctx,
 193                                                struct io_uring_cqe **cqe_ret)
 194 {
 195         io_lockdep_assert_cq_locked(ctx);
 196
 197         ctx->submit_state.cq_flush = true;
 198         return io_get_cqe(ctx, cqe_ret);
 199 }
 200
 201 static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
 202                                             struct io_kiocb *req)
 203 {
 204         struct io_uring_cqe *cqe;
 205
 206         /*
 207          * If we can't get a cq entry, userspace overflowed the
 208          * submission (by quite a lot). Increment the overflow count in
 209          * the ring.
 210          */
 211         if (unlikely(!io_get_cqe(ctx, &cqe)))
 212                 return false;
 213
 214
 215         memcpy(cqe, &req->cqe, sizeof(*cqe));
 216         if (ctx->flags & IORING_SETUP_CQE32) {
 217                 memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
 218                 memset(&req->big_cqe, 0, sizeof(req->big_cqe));
 219         }
 220
 221         if (trace_io_uring_complete_enabled())
 222                 trace_io_uring_complete(req->ctx, req, cqe);
 223         return true;
 224 }
 225
 226 static inline void req_set_fail(struct io_kiocb *req)
 227 {
 228         req->flags |= REQ_F_FAIL;
 229         if (req->flags & REQ_F_CQE_SKIP) {
 230                 req->flags &= ~REQ_F_CQE_SKIP;
 231                 req->flags |= REQ_F_SKIP_LINK_CQES;
 232         }
 233 }
 234
 235 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
 236 {
 237         req->cqe.res = res;
 238         req->cqe.flags = cflags;
 239 }
 240
 241 static inline void *io_uring_alloc_async_data(struct io_alloc_cache *cache,
 242                                               struct io_kiocb *req)
 243 {
 244         if (cache) {
 245                 req->async_data = io_cache_alloc(cache, GFP_KERNEL);
 246         } else {
 247                 const struct io_issue_def *def = &io_issue_defs[req->opcode];
 248
 249                 WARN_ON_ONCE(!def->async_size);
 250                 req->async_data = kmalloc(def->async_size, GFP_KERNEL);
 251         }
 252         if (req->async_data)
 253                 req->flags |= REQ_F_ASYNC_DATA;
 254         return req->async_data;
 255 }
 256
 257 static inline bool req_has_async_data(struct io_kiocb *req)
 258 {
 259         return req->flags & REQ_F_ASYNC_DATA;
 260 }
 261
 262 static inline void io_put_file(struct io_kiocb *req)
 263 {
 264         if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
 265                 fput(req->file);
 266 }
 267
 268 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
 269                                          unsigned issue_flags)
 270 {
 271         lockdep_assert_held(&ctx->uring_lock);
 272         if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
 273                 mutex_unlock(&ctx->uring_lock);
 274 }
 275
 276 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
 277                                        unsigned issue_flags)
 278 {
 279         /*
 280          * "Normal" inline submissions always hold the uring_lock, since we
 281          * grab it from the system call. Same is true for the SQPOLL offload.
 282          * The only exception is when we've detached the request and issue it
 283          * from an async worker thread, grab the lock for that case.
 284          */
 285         if (unlikely(issue_flags & IO_URING_F_UNLOCKED))
 286                 mutex_lock(&ctx->uring_lock);
 287         lockdep_assert_held(&ctx->uring_lock);
 288 }
 289
 290 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
 291 {
 292         /* order cqe stores with ring update */
 293         smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
 294 }
 295
 296 static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
 297 {
 298         if (wq_has_sleeper(&ctx->poll_wq))
 299                 __wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
 300                                 poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 301 }
 302
 303 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
 304 {
 305         /*
 306          * Trigger waitqueue handler on all waiters on our waitqueue. This
 307          * won't necessarily wake up all the tasks, io_should_wake() will make
 308          * that decision.
 309          *
 310          * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
 311          * set in the mask so that if we recurse back into our own poll
 312          * waitqueue handlers, we know we have a dependency between eventfd or
 313          * epoll and should terminate multishot poll at that point.
 314          */
 315         if (wq_has_sleeper(&ctx->cq_wait))
 316                 __wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
 317                                 poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 318 }
 319
 320 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
 321 {
 322         struct io_rings *r = ctx->rings;
 323
 324         /*
 325          * SQPOLL must use the actual sqring head, as using the cached_sq_head
 326          * is race prone if the SQPOLL thread has grabbed entries but not yet
 327          * committed them to the ring. For !SQPOLL, this doesn't matter, but
 328          * since this helper is just used for SQPOLL sqring waits (or POLLOUT),
 329          * just read the actual sqring head unconditionally.
 330          */
 331         return READ_ONCE(r->sq.tail) - READ_ONCE(r->sq.head) == ctx->sq_entries;
 332 }
 333
 334 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
 335 {
 336         struct io_rings *rings = ctx->rings;
 337         unsigned int entries;
 338
 339         /* make sure SQ entry isn't read before tail */
 340         entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
 341         return min(entries, ctx->sq_entries);
 342 }
 343
 344 static inline int io_run_task_work(void)
 345 {
 346         bool ret = false;
 347
 348         /*
 349          * Always check-and-clear the task_work notification signal. With how
 350          * signaling works for task_work, we can find it set with nothing to
 351          * run. We need to clear it for that case, like get_signal() does.
 352          */
 353         if (test_thread_flag(TIF_NOTIFY_SIGNAL))
 354                 clear_notify_signal();
 355         /*
 356          * PF_IO_WORKER never returns to userspace, so check here if we have
 357          * notify work that needs processing.
 358          */
 359         if (current->flags & PF_IO_WORKER) {
 360                 if (test_thread_flag(TIF_NOTIFY_RESUME)) {
 361                         __set_current_state(TASK_RUNNING);
 362                         resume_user_mode_work(NULL);
 363                 }
 364                 if (current->io_uring) {
 365                         unsigned int count = 0;
 366
 367                         __set_current_state(TASK_RUNNING);
 368                         tctx_task_work_run(current->io_uring, UINT_MAX, &count);
 369                         if (count)
 370                                 ret = true;
 371                 }
 372         }
 373         if (task_work_pending(current)) {
 374                 __set_current_state(TASK_RUNNING);
 375                 task_work_run();
 376                 ret = true;
 377         }
 378
 379         return ret;
 380 }
 381
 382 static inline bool io_local_work_pending(struct io_ring_ctx *ctx)
 383 {
 384         return !llist_empty(&ctx->work_llist) || !llist_empty(&ctx->retry_llist);
 385 }
 386
 387 static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
 388 {
 389         return task_work_pending(current) || io_local_work_pending(ctx);
 390 }
 391
 392 static inline void io_tw_lock(struct io_ring_ctx *ctx, io_tw_token_t tw)
 393 {
 394         lockdep_assert_held(&ctx->uring_lock);
 395 }
 396
 397 /*
 398  * Don't complete immediately but use deferred completion infrastructure.
 399  * Protected by ->uring_lock and can only be used either with
 400  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
 401  */
 402 static inline void io_req_complete_defer(struct io_kiocb *req)
 403         __must_hold(&req->ctx->uring_lock)
 404 {
 405         struct io_submit_state *state = &req->ctx->submit_state;
 406
 407         lockdep_assert_held(&req->ctx->uring_lock);
 408
 409         wq_list_add_tail(&req->comp_list, &state->compl_reqs);
 410 }
 411
 412 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
 413 {
 414         if (unlikely(ctx->off_timeout_used ||
 415                      ctx->has_evfd || ctx->poll_activated))
 416                 __io_commit_cqring_flush(ctx);
 417 }
 418
 419 static inline void io_get_task_refs(int nr)
 420 {
 421         struct io_uring_task *tctx = current->io_uring;
 422
 423         tctx->cached_refs -= nr;
 424         if (unlikely(tctx->cached_refs < 0))
 425                 io_task_refs_refill(tctx);
 426 }
 427
 428 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
 429 {
 430         return !ctx->submit_state.free_list.next;
 431 }
 432
 433 extern struct kmem_cache *req_cachep;
 434
 435 static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
 436 {
 437         struct io_kiocb *req;
 438
 439         req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
 440         wq_stack_extract(&ctx->submit_state.free_list);
 441         return req;
 442 }
 443
 444 static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
 445 {
 446         if (unlikely(io_req_cache_empty(ctx))) {
 447                 if (!__io_alloc_req_refill(ctx))
 448                         return false;
 449         }
 450         *req = io_extract_req(ctx);
 451         return true;
 452 }
 453
 454 static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
 455 {
 456         return likely(ctx->submitter_task == current);
 457 }
 458
 459 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
 460 {
 461         return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
 462                       ctx->submitter_task == current);
 463 }
 464
 465 /*
 466  * Terminate the request if either of these conditions are true:
 467  *
 468  * 1) It's being executed by the original task, but that task is marked
 469  *    with PF_EXITING as it's exiting.
 470  * 2) PF_KTHREAD is set, in which case the invoker of the task_work is
 471  *    our fallback task_work.
 472  */
 473 static inline bool io_should_terminate_tw(void)
 474 {
 475         return current->flags & (PF_KTHREAD | PF_EXITING);
 476 }
 477
 478 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
 479 {
 480         io_req_set_res(req, res, 0);
 481         req->io_task_work.func = io_req_task_complete;
 482         io_req_task_work_add(req);
 483 }
 484
 485 /*
 486  * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
 487  * slot.
 488  */
 489 static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
 490 {
 491         if (ctx->flags & IORING_SETUP_SQE128)
 492                 return 2 * sizeof(struct io_uring_sqe);
 493         return sizeof(struct io_uring_sqe);
 494 }
 495
 496 static inline bool io_file_can_poll(struct io_kiocb *req)
 497 {
 498         if (req->flags & REQ_F_CAN_POLL)
 499                 return true;
 500         if (req->file && file_can_poll(req->file)) {
 501                 req->flags |= REQ_F_CAN_POLL;
 502                 return true;
 503         }
 504         return false;
 505 }
 506
 507 static inline ktime_t io_get_time(struct io_ring_ctx *ctx)
 508 {
 509         if (ctx->clockid == CLOCK_MONOTONIC)
 510                 return ktime_get();
 511
 512         return ktime_get_with_offset(ctx->clock_offset);
 513 }
 514
 515 enum {
 516         IO_CHECK_CQ_OVERFLOW_BIT,
 517         IO_CHECK_CQ_DROPPED_BIT,
 518 };
 519
 520 static inline bool io_has_work(struct io_ring_ctx *ctx)
 521 {
 522         return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) ||
 523                io_local_work_pending(ctx);
 524 }
 525 #endif