[PATCH 2/4] net: don not detour through struct sock to find the poll waitqueue

From: Christoph Hellwig
Date: Mon Jul 30 2018 - 03:42:30 EST


For any open socket file descriptor sock->sk->sk_wq->wait will always
point to sock->wq->wait. That means we can do the shorter dereference
and removal a NULL check and don't have to not worry about any RCU
protection.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
include/net/sock.h | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 762069bb0d8c..7927541101a8 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2001,10 +2001,9 @@ static inline bool skwq_has_sleeper(struct socket_wq *wq)
static inline void sock_poll_wait(struct file *filp, poll_table *p)
{
struct socket *sock = filp->private_data;
- wait_queue_head_t *wq = sk_sleep(sock->sk);

- if (!poll_does_not_wait(p) && wq) {
- poll_wait(filp, wq, 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.
*
--
2.18.0