Commit 3afa6d00 authored Aug 20, 2012 by Neil Horman Committed by David S. Miller Aug 24, 2012

cls_cgroup: Allow classifier cgroups to have their classid reset to 0

The network classifier cgroup initalizes each cgroups instance classid value to
0. However, the sock_update_classid function only updates classid's in sockets
if the tasks cgroup classid is not zero, and if it differs from the current
classid. The later check is to prevent cache line dirtying, but the former is
detrimental, as it prevents resetting a classid for a cgroup to 0. While this
is not a common action, it has administrative usefulness (if the admin wants to
disable classification of a certain group temporarily for instance).

Easy fix, just remove the zero check. Tested successfully by myself

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent e6e94e39

net/core/sock.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1230,7 +1230,7 @@ void sock_update_classid(struct sock *sk)
	rcu_read_lock(); /* doing current task, which cannot vanish. */		rcu_read_lock(); /* doing current task, which cannot vanish. */
	classid = task_cls_classid(current);		classid = task_cls_classid(current);
	rcu_read_unlock();		rcu_read_unlock();
	if (classid && classid != sk->sk_classid)		if (classid != sk->sk_classid)
	sk->sk_classid = classid;		sk->sk_classid = classid;
	}		}
	EXPORT_SYMBOL(sock_update_classid);		EXPORT_SYMBOL(sock_update_classid);

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