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