From: Jakub Sitnicki <jakub@cloudflare.com>
Date: Mon, 17 Feb 2020 12:15:29 +0000
Subject: bpf, sk_msg: Don't clear saved sock proto on restore
Patch-mainline: v5.7-rc1
Git-commit: a178b4585865a4c756c41bc5376f63416b7d9271
References: bsc#1177028

There is no need to clear psock->sk_proto when restoring socket protocol
callbacks in sk->sk_prot. The psock is about to get detached from the sock
and eventually destroyed. At worst we will restore the protocol callbacks
and the write callback twice.

This makes reasoning about psock state easier. Once psock is initialized,
we can count on psock->sk_proto always being set.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200217121530.754315-3-jakub@cloudflare.com
Acked-by: Gary Lin <glin@suse.com>
---
 include/linux/skmsg.h |    8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -359,13 +359,7 @@ static inline void sk_psock_restore_prot
 					  struct sk_psock *psock)
 {
 	sk->sk_prot->unhash = psock->saved_unhash;
-
-	if (psock->sk_proto) {
-		tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
-		psock->sk_proto = NULL;
-	} else {
-		sk->sk_write_space = psock->saved_write_space;
-	}
+	tcp_update_ulp(sk, psock->sk_proto, psock->saved_write_space);
 }
 
 static inline void sk_psock_set_state(struct sk_psock *psock,