sock_poll_wait: kill the no longer necessary barrier after poll_wait()

Now that poll_wait() provides a full barrier we can remove smp_mb() from
sock_poll_wait().

Also, the poll_does_not_wait() check before poll_wait() just adds the
unnecessary confusion, kill it. poll_wait() does the same "p && p->_qproc"
check.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250107162736.GA18944@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/include/net/sock.h b/include/net/sock.h
index 7464e9f9f47c503c5a41fd64e9f15c15f3c2c812..305f3ae5edc246069b9f13014e0e6ecdbc9ed269 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2291,7 +2291,7 @@ static inline bool skwq_has_sleeper(struct socket_wq *wq)
 }
 
 /**
- * sock_poll_wait - place memory barrier behind the poll_wait call.
+ * sock_poll_wait - wrapper for the poll_wait call.
  * @filp:           file
  * @sock:           socket to wait on
  * @p:              poll_table
@@ -2301,15 +2301,12 @@ static inline bool skwq_has_sleeper(struct socket_wq *wq)
 static inline void sock_poll_wait(struct file *filp, struct socket *sock,
                                  poll_table *p)
 {
-       if (!poll_does_not_wait(p)) {
-               poll_wait(filp, &sock->wq.wait, p);
-               /* We need to be sure we are in sync with the
-                * socket flags modification.
-                *
-                * This memory barrier is paired in the wq_has_sleeper.
-                */
-               smp_mb();
-       }
+       /* Provides a barrier we need to be sure we are in sync
+        * with the socket flags modification.
+        *
+        * This memory barrier is paired in the wq_has_sleeper.
+        */
+       poll_wait(filp, &sock->wq.wait, p);
 }
 
 static inline void skb_set_hash_from_sk(struct sk_buff *skb, struct sock *sk)