[PATCH RFC 02/11] l2tp: let procfs own the seq_file of /proc/net/pppol2tp

[Christian Brauner]

Declare the seq_operations and the size of the iterator state and let
procfs open and free the seq_file. ->proc_open() only takes the
reference to the network namespace now and ->proc_release() drops that
and the references the iterator holds. Reading the file then no longer
holds up its removal.

Signed-off-by: Christian Brauner (Amutable) <brauner at kernel.org>
---
 net/l2tp/l2tp_ppp.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 4f311d473a64..499e37eb788a 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -1596,21 +1596,17 @@ static const struct seq_operations pppol2tp_seq_ops = {
 	.show		= pppol2tp_seq_show,
 };
 
+/* procfs opened the seq_file and allocated @pd */
 static int pppol2tp_proc_open(struct inode *inode, struct file *file)
 {
-	struct net *net = pde_data(inode);
-	struct pppol2tp_seq_data *pd;
+	struct seq_file *seq = file->private_data;
+	struct pppol2tp_seq_data *pd __maybe_unused = seq->private;
+	struct net *net;
 
-	net = maybe_get_net(net);
+	net = maybe_get_net(pde_data(inode));
 	if (!net)
 		return -ENXIO;
 
-	pd = __seq_open_private(file, &pppol2tp_seq_ops, sizeof(*pd));
-	if (!pd) {
-		put_net(net);
-		return -ENOMEM;
-	}
-
 #ifdef CONFIG_NET_NS
 	pd->p.net = net;
 	netns_tracker_alloc(net, &pd->p.ns_tracker, GFP_KERNEL);
@@ -1633,13 +1629,13 @@ static int pppol2tp_proc_release(struct inode *inode, struct file *file)
 #else
 	put_net(&init_net);
 #endif
-	return seq_release_private(inode, file);
+	return 0;
 }
 
 static const struct proc_ops pppol2tp_proc_ops = {
+	.proc_seq_ops	= &pppol2tp_seq_ops,
+	.proc_state_size = sizeof(struct pppol2tp_seq_data),
 	.proc_open	= pppol2tp_proc_open,
-	.proc_read	= seq_read,
-	.proc_lseek	= seq_lseek,
 	.proc_release	= pppol2tp_proc_release,
 };
 

-- 
2.53.0