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authorEric Dumazet <edumazet@google.com>2013-05-20 06:52:26 +0000
committerDavid S. Miller <davem@davemloft.net>2013-05-20 14:00:42 -0700
commit71cea17ed39fdf1c0634f530ddc6a2c2fc601c2b (patch)
treeec6ec3929a41948fb7fef76cceaebf2f1681f1d8 /net/ipv4/tcp_minisocks.c
parent168fc21a971e4bc821a7838ccc39b7bdaf316c11 (diff)
downloadlinux-71cea17ed39fdf1c0634f530ddc6a2c2fc601c2b.tar.gz
tcp: md5: remove spinlock usage in fast path
TCP md5 code uses per cpu variables but protects access to them with
a shared spinlock, which is a contention point.

[ tcp_md5sig_pool_lock is locked twice per incoming packet ]

Makes things much simpler, by allocating crypto structures once, first
time a socket needs md5 keys, and not deallocating them as they are
really small.

Next step would be to allow crypto allocations being done in a NUMA
aware way.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_minisocks.c')
-rw-r--r--net/ipv4/tcp_minisocks.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 0f0178827259..ab1c08658528 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -317,7 +317,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo)
 			key = tp->af_specific->md5_lookup(sk, sk);
 			if (key != NULL) {
 				tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC);
-				if (tcptw->tw_md5_key && tcp_alloc_md5sig_pool(sk) == NULL)
+				if (tcptw->tw_md5_key && !tcp_alloc_md5sig_pool())
 					BUG();
 			}
 		} while (0);
@@ -358,10 +358,8 @@ void tcp_twsk_destructor(struct sock *sk)
 #ifdef CONFIG_TCP_MD5SIG
 	struct tcp_timewait_sock *twsk = tcp_twsk(sk);
 
-	if (twsk->tw_md5_key) {
-		tcp_free_md5sig_pool();
+	if (twsk->tw_md5_key)
 		kfree_rcu(twsk->tw_md5_key, rcu);
-	}
 #endif
 }
 EXPORT_SYMBOL_GPL(tcp_twsk_destructor);