Re: [PATCH] net: fix lock_sock_bh/unlock_sock_bh

David Miller
2010-05-27T05:23:22Z

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 27 May 2010 07:20:18 +0200

> [PATCH v2] 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>

Looks good, I'll wait for positive testing from Anton before applying
this.