LockD: manage garbage collection timeout per networks namespace

This patch moves next_gc to per-net data.

Note: passed network can be NULL (when Lockd kthread is exiting of Lockd
module is removing).

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/lockd/netns.h b/fs/lockd/netns.h
index ce227e0..97c6c77 100644
--- a/fs/lockd/netns.h
+++ b/fs/lockd/netns.h
@@ -5,6 +5,7 @@
 
 struct lockd_net {
 	unsigned int nlmsvc_users;
+	unsigned long next_gc;
 };
 
 extern int lockd_net_id;