From f6da4fee69860d4a02d14b016021ffb516a25f38 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 24 Apr 2025 12:31:18 +0100 Subject: [PATCH] io_uring/eventfd: open code io_eventfd_grab() io_eventfd_grab() doesn't help wit understanding the path, it'll be simpler to keep the helper open coded. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/5cb53ce3876c2819db9e8055cf41dca4398521db.1745493845.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/eventfd.c | 40 ++++++++++------------------------------ 1 file changed, 10 insertions(+), 30 deletions(-) diff --git a/io_uring/eventfd.c b/io_uring/eventfd.c index 8c2835ac17a0..78f8ab7db104 100644 --- a/io_uring/eventfd.c +++ b/io_uring/eventfd.c @@ -65,38 +65,11 @@ static bool __io_eventfd_signal(struct io_ev_fd *ev_fd) /* * Trigger if eventfd_async isn't set, or if it's set and the caller is - * an async worker. If ev_fd isn't valid, obviously return false. + * an async worker. */ static bool io_eventfd_trigger(struct io_ev_fd *ev_fd) { - if (ev_fd) - return !ev_fd->eventfd_async || io_wq_current_is_worker(); - return false; -} - -/* - * On success, returns with an ev_fd reference grabbed and the RCU read - * lock held. - */ -static struct io_ev_fd *io_eventfd_grab(struct io_ring_ctx *ctx) -{ - struct io_ev_fd *ev_fd; - - /* - * rcu_dereference ctx->io_ev_fd once and use it for both for checking - * and eventfd_signal - */ - ev_fd = rcu_dereference(ctx->io_ev_fd); - - /* - * Check again if ev_fd exists in case an io_eventfd_unregister call - * completed between the NULL check of ctx->io_ev_fd at the start of - * the function and rcu_read_lock. - */ - if (io_eventfd_trigger(ev_fd) && refcount_inc_not_zero(&ev_fd->refs)) - return ev_fd; - - return NULL; + return !ev_fd->eventfd_async || io_wq_current_is_worker(); } void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event) @@ -108,9 +81,16 @@ void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event) return; guard(rcu)(); - ev_fd = io_eventfd_grab(ctx); + ev_fd = rcu_dereference(ctx->io_ev_fd); + /* + * Check again if ev_fd exists in case an io_eventfd_unregister call + * completed between the NULL check of ctx->io_ev_fd at the start of + * the function and rcu_read_lock. + */ if (!ev_fd) return; + if (!io_eventfd_trigger(ev_fd) || !refcount_inc_not_zero(&ev_fd->refs)) + return; if (cqe_event) { /* -- 2.25.1