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| author | Pavel Begunkov <asml.silence@gmail.com> | 2025-04-24 14:31:17 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-04-24 17:33:54 +0300 |
| commit | da01f60f8ad144a8a0844833a8d0f0005b0a7c51 (patch) | |
| tree | 8385a809cbbb528c3d9b906fac4dc5816fbc78b5 | |
| parent | 62f666df765ecaf9cc1892ca056d5c071a335d85 (diff) | |
| download | linux-da01f60f8ad144a8a0844833a8d0f0005b0a7c51.tar.xz | |
io_uring/eventfd: clean up rcu locking
Conditional locking is never welcome if there are better options. Move
rcu locking into io_eventfd_signal(), make it unconditional and use
guards. It also helps with sparse warnings.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/91a925e708ca8a5aa7fee61f96d29b24ea9adeaf.1745493845.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | io_uring/eventfd.c | 24 |
1 files changed, 7 insertions, 17 deletions
diff --git a/io_uring/eventfd.c b/io_uring/eventfd.c index a9da2d0d7510..8c2835ac17a0 100644 --- a/io_uring/eventfd.c +++ b/io_uring/eventfd.c @@ -47,13 +47,6 @@ static void io_eventfd_do_signal(struct rcu_head *rcu) io_eventfd_put(ev_fd); } -static void io_eventfd_release(struct io_ev_fd *ev_fd, bool put_ref) -{ - if (put_ref) - io_eventfd_put(ev_fd); - rcu_read_unlock(); -} - /* * Returns true if the caller should put the ev_fd reference, false if not. */ @@ -89,11 +82,6 @@ static struct io_ev_fd *io_eventfd_grab(struct io_ring_ctx *ctx) { struct io_ev_fd *ev_fd; - if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) - return NULL; - - rcu_read_lock(); - /* * rcu_dereference ctx->io_ev_fd once and use it for both for checking * and eventfd_signal @@ -108,15 +96,18 @@ static struct io_ev_fd *io_eventfd_grab(struct io_ring_ctx *ctx) if (io_eventfd_trigger(ev_fd) && refcount_inc_not_zero(&ev_fd->refs)) return ev_fd; - rcu_read_unlock(); return NULL; } void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event) { - bool skip = false, put_ref = true; + bool skip = false; struct io_ev_fd *ev_fd; + if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) + return; + + guard(rcu)(); ev_fd = io_eventfd_grab(ctx); if (!ev_fd) return; @@ -137,9 +128,8 @@ void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event) spin_unlock(&ctx->completion_lock); } - if (!skip) - put_ref = __io_eventfd_signal(ev_fd); - io_eventfd_release(ev_fd, put_ref); + if (skip || __io_eventfd_signal(ev_fd)) + io_eventfd_put(ev_fd); } int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg, |