io_uring/eventfd: move trigger check into a helper

It's a bit hard to read what guards the triggering, move it into a
helper and add a comment explaining it too. This additionally moves
the ev_fd == NULL check in there as well.

Link: https://lore.kernel.org/r/20240921080307.185186-5-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/eventfd.c b/io_uring/eventfd.c
index 58e76f4d1e0055cbd368e561890a11987f926ab2..0946d3da88d36ef8d78bc629fb4cdd2786b9ed4e 100644 (file)
--- a/io_uring/eventfd.c
+++ b/io_uring/eventfd.c
@@ -63,6 +63,17 @@ static bool __io_eventfd_signal(struct io_ev_fd *ev_fd)
        return true;
 }
 
+/*
+ * 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.
+ */
+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;
+}
+
 void io_eventfd_signal(struct io_ring_ctx *ctx)
 {
        struct io_ev_fd *ev_fd = NULL;
@@ -83,9 +94,7 @@ void io_eventfd_signal(struct io_ring_ctx *ctx)
         * completed between the NULL check of ctx->io_ev_fd at the start of
         * the function and rcu_read_lock.
         */
-       if (unlikely(!ev_fd))
-               return;
-       if (ev_fd->eventfd_async && !io_wq_current_is_worker())
+       if (!io_eventfd_trigger(ev_fd))
                return;
        if (!refcount_inc_not_zero(&ev_fd->refs))
                return;