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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-05-26 19:20:18 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-05-27 00:30:53 -0700 |
| commit | 8a74ad60a546b13bd1096b2a61a7a5c6fd9ae17c (patch) | |
| tree | 3110e7e59883597b5d0f617e8507e15b8f965f3f /include/net/sock.h | |
| parent | a56635a56f2afb3d22d9ce07e8f8d69537416b2d (diff) | |
| download | lwn-8a74ad60a546b13bd1096b2a61a7a5c6fd9ae17c.tar.gz lwn-8a74ad60a546b13bd1096b2a61a7a5c6fd9ae17c.zip | |
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 'include/net/sock.h')
| -rw-r--r-- | include/net/sock.h | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index d2a71b04a5ae..ca241ea14875 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, |