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 <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

include/linux/sunrpc/sched.h

···
 void		rpciod_down(void);
 int		__rpc_wait_for_completion_task(struct rpc_task *task, int (*)(void *));
 #ifdef RPC_DEBUG
-void		rpc_show_tasks(void);
+struct net;
+void		rpc_show_tasks(struct net *);
 #endif
 int		rpc_init_mempool(void);
 void		rpc_destroy_mempool(void);

net/sunrpc/clnt.c

···
 #include <linux/sunrpc/bc_xprt.h>
 
 #include "sunrpc.h"
+#include "netns.h"
 
 #ifdef RPC_DEBUG
 # define RPCDBG_FACILITY	RPCDBG_CALL
···
 /*
  * All RPC clients are linked into this list
  */
-static LIST_HEAD(all_clients);
-static DEFINE_SPINLOCK(rpc_client_lock);
 
 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
 
···
 
 static void rpc_register_client(struct rpc_clnt *clnt)
 {
-	spin_lock(&rpc_client_lock);
-	list_add(&clnt->cl_clients, &all_clients);
-	spin_unlock(&rpc_client_lock);
+	struct sunrpc_net *sn = net_generic(clnt->cl_xprt->xprt_net, sunrpc_net_id);
+
+	spin_lock(&sn->rpc_client_lock);
+	list_add(&clnt->cl_clients, &sn->all_clients);
+	spin_unlock(&sn->rpc_client_lock);
 }
 
 static void rpc_unregister_client(struct rpc_clnt *clnt)
 {
-	spin_lock(&rpc_client_lock);
+	struct sunrpc_net *sn = net_generic(clnt->cl_xprt->xprt_net, sunrpc_net_id);
+
+	spin_lock(&sn->rpc_client_lock);
 	list_del(&clnt->cl_clients);
-	spin_unlock(&rpc_client_lock);
+	spin_unlock(&sn->rpc_client_lock);
 }
 
 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
···
 		task->tk_action, rpc_waitq);
 }
 
-void rpc_show_tasks(void)
+void rpc_show_tasks(struct net *net)
 {
 	struct rpc_clnt *clnt;
 	struct rpc_task *task;
 	int header = 0;
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 
-	spin_lock(&rpc_client_lock);
-	list_for_each_entry(clnt, &all_clients, cl_clients) {
+	spin_lock(&sn->rpc_client_lock);
+	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
 		spin_lock(&clnt->cl_lock);
 		list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
 			if (!header) {
···
 		}
 		spin_unlock(&clnt->cl_lock);
 	}
-	spin_unlock(&rpc_client_lock);
+	spin_unlock(&sn->rpc_client_lock);
 }
 #endif

net/sunrpc/netns.h

···
 
 	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;

net/sunrpc/sunrpc_syms.c

···
 static __net_init int sunrpc_init_net(struct net *net)
 {
 	int err;
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 
 	err = rpc_proc_init(net);
 	if (err)
···
 		goto err_ipmap;
 
 	rpc_pipefs_init_net(net);
+	INIT_LIST_HEAD(&sn->all_clients);
+	spin_lock_init(&sn->rpc_client_lock);
 	return 0;
 
 err_ipmap:

net/sunrpc/sysctl.c

···
 #include <linux/sunrpc/stats.h>
 #include <linux/sunrpc/svc_xprt.h>
 
+#include "netns.h"
+
 /*
  * Declare the debug flags here
  */
···
 		*(unsigned int *) table->data = value;
 		/* Display the RPC tasks on writing to rpc_debug */
 		if (strcmp(table->procname, "rpc_debug") == 0)
-			rpc_show_tasks();
+			rpc_show_tasks(&init_net);
 	} else {
 		if (!access_ok(VERIFY_WRITE, buffer, left))
 			return -EFAULT;