From: Daniel Wagner <redacted>

Do not make the cache line dirty when nothing has changed.
sock_update_classid() does exactly the same thing.

Signed-off-by: Daniel Wagner <redacted>
CC: Neil Horman <redacted>
CC: Tejun Heo <redacted>
CC: Li Zefan <redacted>
---
 net/core/sock.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index c7e60ea..75c4b72 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c

@@ -1190,10 +1190,14 @@ EXPORT_SYMBOL(sock_update_classid);
 
 void sock_update_netprioidx(struct sock *sk)
 {
+	u32 prioidx;
+
 	if (in_interrupt())
 		return;
 
-	sk->sk_cgrp_prioidx = task_netprioidx(current);
+	prioidx = task_netprioidx(current);
+	if (prioidx != sk->sk_cgrp_prioidx)
+		sk->sk_cgrp_prioidx = prioidx;
 }
 EXPORT_SYMBOL_GPL(sock_update_netprioidx);
 #endif

-- 
1.7.10.130.g36e6c