mtd: mtdswap: remove debugfs stats file on teardown

[ Upstream commit 66fb313 ]

mtdswap_add_debugfs() creates an mtdswap_stats debugfs file under the
per-MTD debugfs directory, but mtdswap_remove_dev() never removes it
before freeing the mtdswap_dev.

Store the returned dentry and remove it during device teardown before the
driver-private state is freed.

Fixes: a321590 ("mtd: Add mtdswap block driver")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: neosys007

drivers/mtd/mtdswap.c

@@ -125,6 +125,7 @@ struct mtdswap_dev {
 
 	char *page_buf;
 	char *oob_buf;
+	struct dentry *debugfs_stats;
 };
 
 struct mtdswap_oobdata {
@@ -1262,7 +1263,8 @@ static int mtdswap_add_debugfs(struct mtdswap_dev *d)
 	if (IS_ERR_OR_NULL(root))
 		return -1;
 
-	debugfs_create_file("mtdswap_stats", S_IRUSR, root, d, &mtdswap_fops);
+	d->debugfs_stats = debugfs_create_file("mtdswap_stats", 0400, root,
+					       d, &mtdswap_fops);
 
 	return 0;
 }
@@ -1463,6 +1465,7 @@ static void mtdswap_remove_dev(struct mtd_blktrans_dev *dev)
 {
 	struct mtdswap_dev *d = MTDSWAP_MBD_TO_MTDSWAP(dev);
 
+	debugfs_remove(d->debugfs_stats);
 	del_mtd_blktrans_dev(dev);
 	mtdswap_cleanup(d);
 	kfree(d);