[PATCH RFC 06/11] SUNRPC: let procfs own the seq_file of the cache content file

[Christian Brauner]

Declare the seq_operations and let procfs open and free the seq_file of
/proc/net/rpc/<cache>/content. ->proc_open() and ->proc_release() only
take and drop the module reference and set up ->private now. The
rpc_pipefs file is unchanged. Reading the procfs file then no longer
holds up its removal when the network namespace goes away.

Signed-off-by: Christian Brauner (Amutable) <brauner at kernel.org>
---
 net/sunrpc/cache.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 1ceaea7e01b9..007521e8a57f 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1606,24 +1606,28 @@ static const struct proc_ops cache_channel_proc_ops = {
 	.proc_release	= cache_release_procfs,
 };
 
+/* procfs opens the seq_file */
 static int content_open_procfs(struct inode *inode, struct file *filp)
 {
 	struct cache_detail *cd = pde_data(inode);
 
-	return content_open(inode, filp, cd);
+	if (!cd || !try_module_get(cd->owner))
+		return -EACCES;
+	((struct seq_file *)filp->private_data)->private = cd;
+	return 0;
 }
 
 static int content_release_procfs(struct inode *inode, struct file *filp)
 {
 	struct cache_detail *cd = pde_data(inode);
 
-	return content_release(inode, filp, cd);
+	module_put(cd->owner);
+	return 0;
 }
 
 static const struct proc_ops content_proc_ops = {
+	.proc_seq_ops	= &cache_content_op,
 	.proc_open	= content_open_procfs,
-	.proc_read	= seq_read,
-	.proc_lseek	= seq_lseek,
 	.proc_release	= content_release_procfs,
 };
 

-- 
2.53.0