[PATCH v4] SUNRPC: move per-net operations from svc_destroy()

[Stanislav Kinsbursky]

v4:
1) Added per-net data shutdown by the last kernel thread in nfsd().

v2:
1) Increase per-net usage counted in lockd_up_net(), because of note 2.

The idea is to separate service destruction and per-net operations, because
these are two different things and it's mix looks ugly.

Notes:
1) For NFS server this patch looks ugly (sorry for that). But these place will be
rewritten soon during NFSd containerization.
2) LockD per-net counter increase int lockd_up() was moved prior to
make_socks() to make lockd_down_net() call safe in case of error.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@xxxxxxxxxxxxx>
---
 fs/lockd/svc.c    |   27 +++++++++++++++------------
 fs/nfs/callback.c |    3 +++
 fs/nfsd/nfsctl.c  |   12 +++++++++---
 fs/nfsd/nfssvc.c  |   14 ++++++++++++++
 net/sunrpc/svc.c  |    4 ----
 5 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index b7e92ed..3250f28 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -257,7 +257,7 @@ static int lockd_up_net(struct net *net)
 	struct svc_serv *serv = nlmsvc_rqst->rq_server;
 	int error;
 
-	if (ln->nlmsvc_users)
+	if (ln->nlmsvc_users++)
 		return 0;
 
 	error = svc_rpcb_setup(serv, net);
@@ -272,6 +272,7 @@ static int lockd_up_net(struct net *net)
 err_socks:
 	svc_rpcb_cleanup(serv, net);
 err_rpcb:
+	ln->nlmsvc_users--;
 	return error;
 }
 
@@ -299,6 +300,7 @@ int lockd_up(struct net *net)
 {
 	struct svc_serv *serv;
 	int		error = 0;
+	struct lockd_net *ln = net_generic(net, lockd_net_id);
 
 	mutex_lock(&nlmsvc_mutex);
 	/*
@@ -330,9 +332,11 @@ int lockd_up(struct net *net)
 		goto destroy_and_out;
 	}
 
+	ln->nlmsvc_users++;
+
 	error = make_socks(serv, net);
 	if (error < 0)
-		goto destroy_and_out;
+		goto err_start;
 
 	/*
 	 * Create the kernel thread and wait for it to start.
@@ -344,7 +348,7 @@ int lockd_up(struct net *net)
 		printk(KERN_WARNING
 			"lockd_up: svc_rqst allocation failed, error=%d\n",
 			error);
-		goto destroy_and_out;
+		goto err_start;
 	}
 
 	svc_sock_update_bufs(serv);
@@ -358,7 +362,7 @@ int lockd_up(struct net *net)
 		nlmsvc_rqst = NULL;
 		printk(KERN_WARNING
 			"lockd_up: kthread_run failed, error=%d\n", error);
-		goto destroy_and_out;
+		goto err_start;
 	}
 
 	/*
@@ -368,14 +372,14 @@ int lockd_up(struct net *net)
 destroy_and_out:
 	svc_destroy(serv);
 out:
-	if (!error) {
-		struct lockd_net *ln = net_generic(net, lockd_net_id);
-
-		ln->nlmsvc_users++;
+	if (!error)
 		nlmsvc_users++;
-	}
 	mutex_unlock(&nlmsvc_mutex);
 	return error;
+
+err_start:
+	lockd_down_net(net);
+	goto destroy_and_out;
 }
 EXPORT_SYMBOL_GPL(lockd_up);
 
@@ -386,11 +390,10 @@ void
 lockd_down(struct net *net)
 {
 	mutex_lock(&nlmsvc_mutex);
+	lockd_down_net(net);
 	if (nlmsvc_users) {
-		if (--nlmsvc_users) {
-			lockd_down_net(net);
+		if (--nlmsvc_users)
 			goto out;
-		}
 	} else {
 		printk(KERN_ERR "lockd_down: no users! task=%p\n",
 			nlmsvc_task);
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 26b38fb..cff3940 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -314,6 +314,8 @@ out_err:
 	dprintk("NFS: Couldn't create callback socket or server thread; "
 		"err = %d\n", ret);
 	cb_info->users--;
+	if (serv)
+		svc_shutdown_net(serv, net);
 	goto out;
 }
 
@@ -328,6 +330,7 @@ void nfs_callback_down(int minorversion)
 	cb_info->users--;
 	if (cb_info->users == 0 && cb_info->task != NULL) {
 		kthread_stop(cb_info->task);
+		svc_shutdown_net(cb_info->serv, current->nsproxy->net_ns);
 		svc_exit_thread(cb_info->rqst);
 		cb_info->serv = NULL;
 		cb_info->rqst = NULL;
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 7269988..c55298e 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -661,6 +661,7 @@ static ssize_t __write_ports_addfd(char *buf)
 {
 	char *mesg = buf;
 	int fd, err;
+	struct net *net = &init_net;
 
 	err = get_int(&mesg, &fd);
 	if (err != 0 || fd < 0)
@@ -672,6 +673,8 @@ static ssize_t __write_ports_addfd(char *buf)
 
 	err = svc_addsock(nfsd_serv, fd, buf, SIMPLE_TRANSACTION_LIMIT);
 	if (err < 0) {
+		if (nfsd_serv->sv_nrthreads == 1)
+			svc_shutdown_net(nfsd_serv, net);
 		svc_destroy(nfsd_serv);
 		return err;
 	}
@@ -709,6 +712,7 @@ static ssize_t __write_ports_addxprt(char *buf)
 	char transport[16];
 	struct svc_xprt *xprt;
 	int port, err;
+	struct net *net = &init_net;
 
 	if (sscanf(buf, "%15s %4u", transport, &port) != 2)
 		return -EINVAL;
@@ -720,12 +724,12 @@ static ssize_t __write_ports_addxprt(char *buf)
 	if (err != 0)
 		return err;
 
-	err = svc_create_xprt(nfsd_serv, transport, &init_net,
+	err = svc_create_xprt(nfsd_serv, transport, net,
 				PF_INET, port, SVC_SOCK_ANONYMOUS);
 	if (err < 0)
 		goto out_err;
 
-	err = svc_create_xprt(nfsd_serv, transport, &init_net,
+	err = svc_create_xprt(nfsd_serv, transport, net,
 				PF_INET6, port, SVC_SOCK_ANONYMOUS);
 	if (err < 0 && err != -EAFNOSUPPORT)
 		goto out_close;
@@ -734,12 +738,14 @@ static ssize_t __write_ports_addxprt(char *buf)
 	nfsd_serv->sv_nrthreads--;
 	return 0;
 out_close:
-	xprt = svc_find_xprt(nfsd_serv, transport, &init_net, PF_INET, port);
+	xprt = svc_find_xprt(nfsd_serv, transport, net, PF_INET, port);
 	if (xprt != NULL) {
 		svc_close_xprt(xprt);
 		svc_xprt_put(xprt);
 	}
 out_err:
+	if (nfsd_serv->sv_nrthreads == 1)
+		svc_shutdown_net(nfsd_serv, net);
 	svc_destroy(nfsd_serv);
 	return err;
 }
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 0762f3c..ee709fc 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -382,6 +382,7 @@ int nfsd_set_nrthreads(int n, int *nthreads)
 	int i = 0;
 	int tot = 0;
 	int err = 0;
+	struct net *net = &init_net;
 
 	WARN_ON(!mutex_is_locked(&nfsd_mutex));
 
@@ -426,6 +427,9 @@ int nfsd_set_nrthreads(int n, int *nthreads)
 		if (err)
 			break;
 	}
+
+	if (nfsd_serv->sv_nrthreads == 1)
+		svc_shutdown_net(nfsd_serv, net);
 	svc_destroy(nfsd_serv);
 
 	return err;
@@ -441,6 +445,7 @@ nfsd_svc(unsigned short port, int nrservs)
 {
 	int	error;
 	bool	nfsd_up_before;
+	struct net *net = &init_net;
 
 	mutex_lock(&nfsd_mutex);
 	dprintk("nfsd: creating service\n");
@@ -473,6 +478,8 @@ out_shutdown:
 	if (error < 0 && !nfsd_up_before)
 		nfsd_shutdown();
 out_destroy:
+	if (nfsd_serv->sv_nrthreads == 1)
+		svc_shutdown_net(nfsd_serv, net);
 	svc_destroy(nfsd_serv);		/* Release server */
 out:
 	mutex_unlock(&nfsd_mutex);
@@ -556,6 +563,9 @@ nfsd(void *vrqstp)
 	nfsdstats.th_cnt --;
 
 out:
+	if (rqstp->rq_server->sv_nrthreads == 1)
+		svc_shutdown_net(rqstp->rq_server, &init_net);
+
 	/* Release the thread */
 	svc_exit_thread(rqstp);
 
@@ -668,8 +678,12 @@ int nfsd_pool_stats_open(struct inode *inode, struct file *file)
 int nfsd_pool_stats_release(struct inode *inode, struct file *file)
 {
 	int ret = seq_release(inode, file);
+	struct net *net = &init_net;
+
 	mutex_lock(&nfsd_mutex);
 	/* this function really, really should have been called svc_put() */
+	if (nfsd_serv->sv_nrthreads == 1)
+		svc_shutdown_net(nfsd_serv, net);
 	svc_destroy(nfsd_serv);
 	mutex_unlock(&nfsd_mutex);
 	return ret;
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index e6d542c..b7210f5 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -537,8 +537,6 @@ EXPORT_SYMBOL_GPL(svc_shutdown_net);
 void
 svc_destroy(struct svc_serv *serv)
 {
-	struct net *net = current->nsproxy->net_ns;
-
 	dprintk("svc: svc_destroy(%s, %d)\n",
 				serv->sv_program->pg_name,
 				serv->sv_nrthreads);
@@ -553,8 +551,6 @@ svc_destroy(struct svc_serv *serv)
 
 	del_timer_sync(&serv->sv_temptimer);
 
-	svc_shutdown_net(serv, net);
-
 	/*
 	 * The last user is gone and thus all sockets have to be destroyed to
 	 * the point. Check this.

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