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 <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>

diff --git a/io_uring/eventfd.c b/io_uring/eventfd.c
index 8c2835ac17a0b4f2b438285c290688dbe24b41a7..78f8ab7db104f018a3442db35d64dcb6cdfde3ef 100644 (file)
--- 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) {
                /*