Merge branch 'sunrpc-netns-refcnt-tracking'

Eric Dumazet says:

====================
SUNRPC: add some netns refcount trackers

Effort started in linux-5.17

Our goal is to replace get_net()/put_net() pairs with
get_net_track()/put_net_track() to get instant notifications
of imbalance bugs in the future.

Patches were split from a bigger series sent one month ago.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/sunrpc/svc_xprt.h

@@ -88,6 +88,7 @@ struct svc_xprt {
 	struct list_head	xpt_users;	/* callbacks on free */
 
 	struct net		*xpt_net;
+	netns_tracker		ns_tracker;
 	const struct cred	*xpt_cred;
 	struct rpc_xprt		*xpt_bc_xprt;	/* NFSv4.1 backchannel */
 	struct rpc_xprt_switch	*xpt_bc_xps;	/* NFSv4.1 backchannel */

include/linux/sunrpc/xprt.h

@@ -284,6 +284,7 @@ struct rpc_xprt {
 	} stat;
 
 	struct net		*xprt_net;
+	netns_tracker		ns_tracker;
 	const char		*servername;
 	const char		*address_strings[RPC_DISPLAY_MAX];
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)

net/sunrpc/auth_gss/auth_gss.c

@@ -72,7 +72,8 @@ struct gss_auth {
 	struct gss_api_mech *mech;
 	enum rpc_gss_svc service;
 	struct rpc_clnt *client;
-	struct net *net;
+	struct net	*net;
+	netns_tracker	ns_tracker;
 	/*
 	 * There are two upcall pipes; dentry[1], named "gssd", is used
 	 * for the new text-based upcall; dentry[0] is named after the
@@ -1013,7 +1014,8 @@ gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 			goto err_free;
 	}
 	gss_auth->client = clnt;
-	gss_auth->net = get_net(rpc_net_ns(clnt));
+	gss_auth->net = get_net_track(rpc_net_ns(clnt), &gss_auth->ns_tracker,
+				      GFP_KERNEL);
 	err = -EINVAL;
 	gss_auth->mech = gss_mech_get_by_pseudoflavor(flavor);
 	if (!gss_auth->mech)
@@ -1068,7 +1070,7 @@ gss_create_new(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 err_put_mech:
 	gss_mech_put(gss_auth->mech);
 err_put_net:
-	put_net(gss_auth->net);
+	put_net_track(gss_auth->net, &gss_auth->ns_tracker);
 err_free:
 	kfree(gss_auth->target_name);
 	kfree(gss_auth);
@@ -1084,7 +1086,7 @@ gss_free(struct gss_auth *gss_auth)
 	gss_pipe_free(gss_auth->gss_pipe[0]);
 	gss_pipe_free(gss_auth->gss_pipe[1]);
 	gss_mech_put(gss_auth->mech);
-	put_net(gss_auth->net);
+	put_net_track(gss_auth->net, &gss_auth->ns_tracker);
 	kfree(gss_auth->target_name);
 
 	kfree(gss_auth);

net/sunrpc/svc_xprt.c

@@ -162,7 +162,7 @@ static void svc_xprt_free(struct kref *kref)
 	if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
 		svcauth_unix_info_release(xprt);
 	put_cred(xprt->xpt_cred);
-	put_net(xprt->xpt_net);
+	put_net_track(xprt->xpt_net, &xprt->ns_tracker);
 	/* See comment on corresponding get in xs_setup_bc_tcp(): */
 	if (xprt->xpt_bc_xprt)
 		xprt_put(xprt->xpt_bc_xprt);
@@ -198,7 +198,7 @@ void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
 	mutex_init(&xprt->xpt_mutex);
 	spin_lock_init(&xprt->xpt_lock);
 	set_bit(XPT_BUSY, &xprt->xpt_flags);
-	xprt->xpt_net = get_net(net);
+	xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC);
 	strcpy(xprt->xpt_remotebuf, "uninitialized");
 }
 EXPORT_SYMBOL_GPL(svc_xprt_init);

net/sunrpc/xprt.c

@@ -1835,7 +1835,7 @@ EXPORT_SYMBOL_GPL(xprt_alloc);
 
 void xprt_free(struct rpc_xprt *xprt)
 {
-	put_net(xprt->xprt_net);
+	put_net_track(xprt->xprt_net, &xprt->ns_tracker);
 	xprt_free_all_slots(xprt);
 	xprt_free_id(xprt);
 	rpc_sysfs_xprt_destroy(xprt);
@@ -2027,7 +2027,7 @@ static void xprt_init(struct rpc_xprt *xprt, struct net *net)
 
 	xprt_init_xid(xprt);
 
-	xprt->xprt_net = get_net(net);
+	xprt->xprt_net = get_net_track(net, &xprt->ns_tracker, GFP_KERNEL);
 }
 
 /**