netdev - [PATCH 4/6] net: remove busy polling from sock_get_poll

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Date:   Thu, 28 Jun 2018 16:20:57 +0200
From:   Christoph Hellwig <hch@....de>
To:     Alexander Viro <viro@...iv.linux.org.uk>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org, netdev@...r.kernel.org, lkp@...org
Subject: [PATCH 4/6] net: remove busy polling from sock_get_poll_head

Busy polling always comes from a synchronous poll context, so for now we
can assume that it calls ->poll if present.  Move the busy polling in
sock_poll to the common block and remove it from sock_get_poll_head to
prepare for the removal of the get_poll_head method.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 net/socket.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 7cf037d21805..ca300c97b7ba 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -1135,7 +1135,6 @@ static struct wait_queue_head *sock_get_poll_head(struct file *file,
 
 	if (!sock->ops->poll_mask)
 		return NULL;
-	sock_poll_busy_loop(sock, events);
 	return &sock->wq->wait;
 }
 
@@ -1161,8 +1160,9 @@ static __poll_t sock_poll(struct file *file, poll_table *wait)
 	struct socket *sock = file->private_data;
 	__poll_t events = poll_requested_events(wait), mask = 0;
 
+	sock_poll_busy_loop(sock, events);
+
 	if (sock->ops->poll) {
-		sock_poll_busy_loop(sock, events);
 		mask = sock->ops->poll(file, sock, wait);
 	} else if (sock->ops->poll_mask) {
 		sock_poll_wait(file, sock_get_poll_head(file, events), wait);
-- 
2.17.1