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authorEric Dumazet <eric.dumazet@gmail.com>2010-05-26 19:20:18 +0000
committerDavid S. Miller <davem@davemloft.net>2010-05-27 00:30:53 -0700
commit8a74ad60a546b13bd1096b2a61a7a5c6fd9ae17c (patch)
tree3110e7e59883597b5d0f617e8507e15b8f965f3f /net/ipv6
parenta56635a56f2afb3d22d9ce07e8f8d69537416b2d (diff)
downloadlinux-2.6.34-ux500-8a74ad60a546b13bd1096b2a61a7a5c6fd9ae17c.tar.gz
net: fix lock_sock_bh/unlock_sock_bh
This new sock lock primitive was introduced to speedup some user context socket manipulation. But it is unsafe to protect two threads, one using regular lock_sock/release_sock, one using lock_sock_bh/unlock_sock_bh This patch changes lock_sock_bh to be careful against 'owned' state. If owned is found to be set, we must take the slow path. lock_sock_bh() now returns a boolean to say if the slow path was taken, and this boolean is used at unlock_sock_bh time to call the appropriate unlock function. After this change, BH are either disabled or enabled during the lock_sock_bh/unlock_sock_bh protected section. This might be misleading, so we rename these functions to lock_sock_fast()/unlock_sock_fast(). Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/udp.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 3d7a2c0b836..87be58673b5 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -328,6 +328,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
int err;
int is_udplite = IS_UDPLITE(sk);
int is_udp4;
+ bool slow;
if (addr_len)
*addr_len=sizeof(struct sockaddr_in6);
@@ -424,7 +425,7 @@ out:
return err;
csum_copy_err:
- lock_sock_bh(sk);
+ slow = lock_sock_fast(sk);
if (!skb_kill_datagram(sk, skb, flags)) {
if (is_udp4)
UDP_INC_STATS_USER(sock_net(sk),
@@ -433,7 +434,7 @@ csum_copy_err:
UDP6_INC_STATS_USER(sock_net(sk),
UDP_MIB_INERRORS, is_udplite);
}
- unlock_sock_bh(sk);
+ unlock_sock_fast(sk, slow);
if (flags & MSG_DONTWAIT)
return -EAGAIN;