[PATCH -next v2] bcache: Convert to DEFINE_SHOW_ATTRIBUTE

[Qinglang Miao <miaoqinglang@huawei.com>]

Use DEFINE_SHOW_ATTRIBUTE macro to simplify the code.

As inode->iprivate equals to third parameter of
debugfs_create_file() which is NULL. So it's equivalent
to original code logic.

Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
---
v2: based on linux-next(20200917), and can be applied to
    mainline cleanly now.

 drivers/md/bcache/closure.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/md/bcache/closure.c b/drivers/md/bcache/closure.c
index 0164a1fe9..d8d9394a6 100644
--- a/drivers/md/bcache/closure.c
+++ b/drivers/md/bcache/closure.c
@@ -159,7 +159,7 @@ void closure_debug_destroy(struct closure *cl)
 
 static struct dentry *closure_debug;
 
-static int debug_seq_show(struct seq_file *f, void *data)
+static int debug_show(struct seq_file *f, void *data)
 {
 	struct closure *cl;
 
@@ -188,17 +188,7 @@ static int debug_seq_show(struct seq_file *f, void *data)
 	return 0;
 }
 
-static int debug_seq_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, debug_seq_show, NULL);
-}
-
-static const struct file_operations debug_ops = {
-	.owner		= THIS_MODULE,
-	.open		= debug_seq_open,
-	.read		= seq_read,
-	.release	= single_release
-};
+DEFINE_SHOW_ATTRIBUTE(debug);
 
 void  __init closure_debug_init(void)
 {
@@ -209,7 +199,7 @@ void  __init closure_debug_init(void)
 		 * about this.
 		 */
 		closure_debug = debugfs_create_file(
-			"closures", 0400, bcache_debug, NULL, &debug_ops);
+			"closures", 0400, bcache_debug, NULL, &debug_fops);
 }
 #endif
 
-- 
2.23.0