[PATCH v3 2/3] SUNRPC: optimize net_ns dereferencing in rpcbind creation calls

[Stanislav Kinsbursky <skinsbursky@parallels.com>]

Static rpcbind creation functions can be parametrized by network namespace
pointer, calculated only once, instead of using init_net pointer (or taking it
from current when virtualization will be comleted) in many places.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>

---
 net/sunrpc/rpcb_clnt.c |   35 +++++++++++++++++++----------------
 1 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c
index 59bd1fb..8c873a8 100644
--- a/net/sunrpc/rpcb_clnt.c
+++ b/net/sunrpc/rpcb_clnt.c
@@ -161,10 +161,10 @@ static void rpcb_map_release(void *data)
 	kfree(map);
 }
 
-static int rpcb_get_local(void)
+static int rpcb_get_local(struct net *net)
 {
 	int cnt;
-	struct sunrpc_net *sn = net_generic(&init_net, sunrpc_net_id);
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 
 	spin_lock(&sn->rpcb_clnt_lock);
 	if (sn->rpcb_users)
@@ -201,9 +201,10 @@ void rpcb_put_local(void)
 	}
 }
 
-static void rpcb_set_local(struct rpc_clnt *clnt, struct rpc_clnt *clnt4)
+static void rpcb_set_local(struct net *net, struct rpc_clnt *clnt,
+			struct rpc_clnt *clnt4)
 {
-	struct sunrpc_net *sn = net_generic(&init_net, sunrpc_net_id);
+	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 
 	/* Protected by rpcb_create_local_mutex */
 	sn->rpcb_local_clnt = clnt;
@@ -211,22 +212,23 @@ static void rpcb_set_local(struct rpc_clnt *clnt, struct rpc_clnt *clnt4)
 	smp_wmb(); 
 	sn->rpcb_users = 1;
 	dprintk("RPC:       created new rpcb local clients (rpcb_local_clnt: "
-			"%p, rpcb_local_clnt4: %p)\n", sn->rpcb_local_clnt,
-			sn->rpcb_local_clnt4);
+			"%p, rpcb_local_clnt4: %p) for net %p%s\n",
+			sn->rpcb_local_clnt, sn->rpcb_local_clnt4,
+			net, (net == &init_net) ? " (init_net)" : "");
 }
 
 /*
  * Returns zero on success, otherwise a negative errno value
  * is returned.
  */
-static int rpcb_create_local_unix(void)
+static int rpcb_create_local_unix(struct net *net)
 {
 	static const struct sockaddr_un rpcb_localaddr_rpcbind = {
 		.sun_family		= AF_LOCAL,
 		.sun_path		= RPCBIND_SOCK_PATHNAME,
 	};
 	struct rpc_create_args args = {
-		.net		= &init_net,
+		.net		= net,
 		.protocol	= XPRT_TRANSPORT_LOCAL,
 		.address	= (struct sockaddr *)&rpcb_localaddr_rpcbind,
 		.addrsize	= sizeof(rpcb_localaddr_rpcbind),
@@ -259,7 +261,7 @@ static int rpcb_create_local_unix(void)
 		clnt4 = NULL;
 	}
 
-	rpcb_set_local(clnt, clnt4);
+	rpcb_set_local(net, clnt, clnt4);
 
 out:
 	return result;
@@ -269,7 +271,7 @@ out:
  * Returns zero on success, otherwise a negative errno value
  * is returned.
  */
-static int rpcb_create_local_net(void)
+static int rpcb_create_local_net(struct net *net)
 {
 	static const struct sockaddr_in rpcb_inaddr_loopback = {
 		.sin_family		= AF_INET,
@@ -277,7 +279,7 @@ static int rpcb_create_local_net(void)
 		.sin_port		= htons(RPCBIND_PORT),
 	};
 	struct rpc_create_args args = {
-		.net		= &init_net,
+		.net		= net,
 		.protocol	= XPRT_TRANSPORT_TCP,
 		.address	= (struct sockaddr *)&rpcb_inaddr_loopback,
 		.addrsize	= sizeof(rpcb_inaddr_loopback),
@@ -311,7 +313,7 @@ static int rpcb_create_local_net(void)
 		clnt4 = NULL;
 	}
 
-	rpcb_set_local(clnt, clnt4);
+	rpcb_set_local(net, clnt, clnt4);
 
 out:
 	return result;
@@ -325,16 +327,17 @@ int rpcb_create_local(void)
 {
 	static DEFINE_MUTEX(rpcb_create_local_mutex);
 	int result = 0;
+	struct net *net = &init_net;
 
-	if (rpcb_get_local())
+	if (rpcb_get_local(net))
 		return result;
 
 	mutex_lock(&rpcb_create_local_mutex);
-	if (rpcb_get_local())
+	if (rpcb_get_local(net))
 		goto out;
 
-	if (rpcb_create_local_unix() != 0)
-		result = rpcb_create_local_net();
+	if (rpcb_create_local_unix(net) != 0)
+		result = rpcb_create_local_net(net);
 
 out:
 	mutex_unlock(&rpcb_create_local_mutex);