netdev - [PATCH bpf-next v5 01/12] bpf, sk_msg: Don't clear saved sock proto on restore

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Message-Id: <20200127125534.137492-2-jakub@cloudflare.com>
Date:   Mon, 27 Jan 2020 13:55:23 +0100
From:   Jakub Sitnicki <jakub@...udflare.com>
To:     bpf@...r.kernel.org
Cc:     netdev@...r.kernel.org, kernel-team@...udflare.com,
        John Fastabend <john.fastabend@...il.com>
Subject: [PATCH bpf-next v5 01/12] bpf, sk_msg: Don't clear saved sock proto on restore

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.

Also, we don't need a fallback for when socket is not using ULP.
tcp_update_ulp already does this for us.

Acked-by: John Fastabend <john.fastabend@...il.com>
Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
---
 include/linux/skmsg.h | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14d61bba0b79..d90ef61712a1 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -359,22 +359,7 @@ static inline void sk_psock_restore_proto(struct sock *sk,
 					  struct sk_psock *psock)
 {
 	sk->sk_prot->unhash = psock->saved_unhash;
-
-	if (psock->sk_proto) {
-		struct inet_connection_sock *icsk = inet_csk(sk);
-		bool has_ulp = !!icsk->icsk_ulp_data;
-
-		if (has_ulp) {
-			tcp_update_ulp(sk, psock->sk_proto,
-				       psock->saved_write_space);
-		} else {
-			sk->sk_prot = psock->sk_proto;
-			sk->sk_write_space = 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,
-- 
2.24.1