[PATCH 1/2] net: handle NULL ->poll gracefully

The big aio poll revert broke various network protocols that don't
implement ->poll as a patch in the aio poll serie removed sock_no_poll
and made the common code handle this case.

Fixes: a11e1d43 ("Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 net/socket.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/socket.c b/net/socket.c
index a564c6ed19d5..85633622c94d 100644
--- a/net/socket.c
+++ b/net/socket.c

@@ -1133,6 +1133,8 @@ static __poll_t sock_poll(struct file *file, poll_table *wait)
 	__poll_t events = poll_requested_events(wait);
 
 	sock_poll_busy_loop(sock, events);
+	if (!sock->ops->poll)
+		return 0;
 	return sock->ops->poll(file, sock, wait) | sock_poll_busy_flag(sock);
 }
 

-- 
2.18.0