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io_uring/eventfd: open code io_eventfd_grab()

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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 <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5cb53ce3876c2819db9e8055cf41dca4398521db.1745493845.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2025-04-24 12:31:18 +01:00 • committed by Jens Axboe
parent da01f60f8a
commit f6da4fee69
1 changed files with 10 additions and 30 deletions
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40
io_uring/eventfd.c
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@ -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 * 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) 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 !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;
} }
void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event) 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; return;
guard(rcu)(); 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) if (!ev_fd)
return; return;
if (!io_eventfd_trigger(ev_fd) || !refcount_inc_not_zero(&ev_fd->refs))
return;
if (cqe_event) { if (cqe_event) {
/* /*