From: Eric Dumazet <edumazet@google.com>
Date: Sun, 21 Oct 2012 20:06:56 +0000 (+0000)
Subject: tcp: speedup SIOCINQ ioctl
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~17633^2~603
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=0e71c55c9e3eb32de08e17152ec739582afc9400;p=mirror_ubuntu-focal-kernel.git

tcp: speedup SIOCINQ ioctl

SIOCINQ can use the lock_sock_fast() version to avoid double acquisition
of socket lock.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b7c2f439b54f..eace049da052 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -536,13 +536,14 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	int answ;
+	bool slow;
 
 	switch (cmd) {
 	case SIOCINQ:
 		if (sk->sk_state == TCP_LISTEN)
 			return -EINVAL;
 
-		lock_sock(sk);
+		slow = lock_sock_fast(sk);
 		if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))
 			answ = 0;
 		else if (sock_flag(sk, SOCK_URGINLINE) ||
@@ -557,7 +558,7 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg)
 				answ--;
 		} else
 			answ = tp->urg_seq - tp->copied_seq;
-		release_sock(sk);
+		unlock_sock_fast(sk, slow);
 		break;
 	case SIOCATMARK:
 		answ = tp->urg_data && tp->urg_seq == tp->copied_seq;