diff options
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/io_uring.c | 62 | ||||
| -rw-r--r-- | io_uring/io_uring.h | 34 |
2 files changed, 69 insertions, 27 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index ac1a5cf10287..84fb1f7b0d81 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -189,12 +189,15 @@ static void io_poison_req(struct io_kiocb *req) static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx) { - return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head); + struct io_rings *rings = io_get_rings(ctx); + return ctx->cached_cq_tail - READ_ONCE(rings->cq.head); } static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx) { - return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head); + struct io_rings *rings = io_get_rings(ctx); + + return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head); } static inline void req_fail_link_node(struct io_kiocb *req, int res) @@ -2536,12 +2539,15 @@ static enum hrtimer_restart io_cqring_min_timer_wakeup(struct hrtimer *timer) if (io_has_work(ctx)) goto out_wake; /* got events since we started waiting, min timeout is done */ - if (iowq->cq_min_tail != READ_ONCE(ctx->rings->cq.tail)) - goto out_wake; - /* if we have any events and min timeout expired, we're done */ - if (io_cqring_events(ctx)) - goto out_wake; + scoped_guard(rcu) { + struct io_rings *rings = io_get_rings(ctx); + if (iowq->cq_min_tail != READ_ONCE(rings->cq.tail)) + goto out_wake; + /* if we have any events and min timeout expired, we're done */ + if (io_cqring_events(ctx)) + goto out_wake; + } /* * If using deferred task_work running and application is waiting on * more than one request, ensure we reset it now where we are switching @@ -2652,9 +2658,9 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags, struct ext_arg *ext_arg) { struct io_wait_queue iowq; - struct io_rings *rings = ctx->rings; + struct io_rings *rings; ktime_t start_time; - int ret; + int ret, nr_wait; min_events = min_t(int, min_events, ctx->cq_entries); @@ -2667,15 +2673,23 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags, if (unlikely(test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))) io_cqring_do_overflow_flush(ctx); - if (__io_cqring_events_user(ctx) >= min_events) + + rcu_read_lock(); + rings = io_get_rings(ctx); + if (__io_cqring_events_user(ctx) >= min_events) { + rcu_read_unlock(); return 0; + } init_waitqueue_func_entry(&iowq.wq, io_wake_function); iowq.wq.private = current; INIT_LIST_HEAD(&iowq.wq.entry); iowq.ctx = ctx; - iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events; - iowq.cq_min_tail = READ_ONCE(ctx->rings->cq.tail); + iowq.cq_tail = READ_ONCE(rings->cq.head) + min_events; + iowq.cq_min_tail = READ_ONCE(rings->cq.tail); + nr_wait = (int) iowq.cq_tail - READ_ONCE(rings->cq.tail); + rcu_read_unlock(); + rings = NULL; iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); iowq.hit_timeout = 0; iowq.min_timeout = ext_arg->min_time; @@ -2706,14 +2720,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags, trace_io_uring_cqring_wait(ctx, min_events); do { unsigned long check_cq; - int nr_wait; - - /* if min timeout has been hit, don't reset wait count */ - if (!iowq.hit_timeout) - nr_wait = (int) iowq.cq_tail - - READ_ONCE(ctx->rings->cq.tail); - else - nr_wait = 1; if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { atomic_set(&ctx->cq_wait_nr, nr_wait); @@ -2764,13 +2770,22 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags, break; } cond_resched(); + + /* if min timeout has been hit, don't reset wait count */ + if (!iowq.hit_timeout) + scoped_guard(rcu) + nr_wait = (int) iowq.cq_tail - + READ_ONCE(io_get_rings(ctx)->cq.tail); + else + nr_wait = 1; } while (1); if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) finish_wait(&ctx->cq_wait, &iowq.wq); restore_saved_sigmask_unless(ret == -EINTR); - return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0; + guard(rcu)(); + return READ_ONCE(io_get_rings(ctx)->cq.head) == READ_ONCE(io_get_rings(ctx)->cq.tail) ? ret : 0; } static void io_rings_free(struct io_ring_ctx *ctx) @@ -2954,7 +2969,9 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait) */ poll_wait(file, &ctx->poll_wq, wait); - if (!io_sqring_full(ctx)) + rcu_read_lock(); + + if (!__io_sqring_full(ctx)) mask |= EPOLLOUT | EPOLLWRNORM; /* @@ -2974,6 +2991,7 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait) if (__io_cqring_events_user(ctx) || io_has_work(ctx)) mask |= EPOLLIN | EPOLLRDNORM; + rcu_read_unlock(); return mask; } diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index 0f096f44d34b..6ee49991cec8 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -132,16 +132,28 @@ struct io_wait_queue { #endif }; +static inline struct io_rings *io_get_rings(struct io_ring_ctx *ctx) +{ + return rcu_dereference_check(ctx->rings_rcu, + lockdep_is_held(&ctx->uring_lock) || + lockdep_is_held(&ctx->completion_lock)); +} + static inline bool io_should_wake(struct io_wait_queue *iowq) { struct io_ring_ctx *ctx = iowq->ctx; - int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail; + struct io_rings *rings; + int dist; + + guard(rcu)(); + rings = io_get_rings(ctx); /* * Wake up if we have enough events, or if a timeout occurred since we * started waiting. For timeouts, we always want to return to userspace, * regardless of event count. */ + dist = READ_ONCE(rings->cq.tail) - (int) iowq->cq_tail; return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; } @@ -432,9 +444,9 @@ static inline void io_cqring_wake(struct io_ring_ctx *ctx) __io_wq_wake(&ctx->cq_wait); } -static inline bool io_sqring_full(struct io_ring_ctx *ctx) +static inline bool __io_sqring_full(struct io_ring_ctx *ctx) { - struct io_rings *r = ctx->rings; + struct io_rings *r = io_get_rings(ctx); /* * SQPOLL must use the actual sqring head, as using the cached_sq_head @@ -446,9 +458,15 @@ static inline bool io_sqring_full(struct io_ring_ctx *ctx) return READ_ONCE(r->sq.tail) - READ_ONCE(r->sq.head) == ctx->sq_entries; } -static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) +static inline bool io_sqring_full(struct io_ring_ctx *ctx) { - struct io_rings *rings = ctx->rings; + guard(rcu)(); + return __io_sqring_full(ctx); +} + +static inline unsigned int __io_sqring_entries(struct io_ring_ctx *ctx) +{ + struct io_rings *rings = io_get_rings(ctx); unsigned int entries; /* make sure SQ entry isn't read before tail */ @@ -509,6 +527,12 @@ static inline void io_tw_lock(struct io_ring_ctx *ctx, io_tw_token_t tw) lockdep_assert_held(&ctx->uring_lock); } +static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) +{ + guard(rcu)(); + return __io_sqring_entries(ctx); +} + /* * Don't complete immediately but use deferred completion infrastructure. * Protected by ->uring_lock and can only be used either with |