SUNRPC: make SUNPRC clients list per network namespace context

This patch moves static SUNRPC clients list and it's lock to sunrpc_net
structure.
Currently this list is used only for debug purposes. But later it will be used
also for selecting clients by networks namespace on PipeFS mount/umount events.
Per-network namespace lists will make this faster and simplier.

Note: client list is taken from "init_net" network namespace context in
rpc_show_tasks(). This will be changed some day later with making SUNRPC
sysctl's per network namespace context.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/netns.h b/net/sunrpc/netns.h
index 11d2f48..0f3af34 100644
--- a/net/sunrpc/netns.h
+++ b/net/sunrpc/netns.h
@@ -12,6 +12,9 @@
 
 	struct super_block *pipefs_sb;
 	struct mutex pipefs_sb_lock;
+
+	struct list_head all_clients;
+	spinlock_t rpc_client_lock;
 };
 
 extern int sunrpc_net_id;