From 8a74ad60a546b13bd1096b2a61a7a5c6fd9ae17c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 26 May 2010 19:20:18 +0000 Subject: 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 Signed-off-by: Eric Dumazet Tested-by: Anton Blanchard Signed-off-by: David S. Miller --- include/net/sock.h | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'include/net/sock.h') diff --git a/include/net/sock.h b/include/net/sock.h index d2a71b0..ca241ea 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1026,15 +1026,23 @@ extern void release_sock(struct sock *sk); SINGLE_DEPTH_NESTING) #define bh_unlock_sock(__sk) spin_unlock(&((__sk)->sk_lock.slock)) -static inline void lock_sock_bh(struct sock *sk) +extern bool lock_sock_fast(struct sock *sk); +/** + * unlock_sock_fast - complement of lock_sock_fast + * @sk: socket + * @slow: slow mode + * + * fast unlock socket for user context. + * If slow mode is on, we call regular release_sock() + */ +static inline void unlock_sock_fast(struct sock *sk, bool slow) { - spin_lock_bh(&sk->sk_lock.slock); + if (slow) + release_sock(sk); + else + spin_unlock_bh(&sk->sk_lock.slock); } -static inline void unlock_sock_bh(struct sock *sk) -{ - spin_unlock_bh(&sk->sk_lock.slock); -} extern struct sock *sk_alloc(struct net *net, int family, gfp_t priority, -- cgit v1.1