mtd: spi-nor: fix memory leak when using debugfs_lookup()

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To solve this, remove the
lookup and create the directory on the first device found, and then
remove it when the module is unloaded.

Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>
Cc: linux-mtd@lists.infradead.org
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20230208160230.2179905-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/mtd/spi-nor/debugfs.c b/drivers/mtd/spi-nor/debugfs.c
index 845b78c7ecc7..fc7ad203df12 100644
--- a/drivers/mtd/spi-nor/debugfs.c
+++ b/drivers/mtd/spi-nor/debugfs.c
@@ -226,13 +226,13 @@ static void spi_nor_debugfs_unregister(void *data)
 	nor->debugfs_root = NULL;
 }
 
+static struct dentry *rootdir;
+
 void spi_nor_debugfs_register(struct spi_nor *nor)
 {
-	struct dentry *rootdir, *d;
+	struct dentry *d;
 	int ret;
 
-	/* Create rootdir once. Will never be deleted again. */
-	rootdir = debugfs_lookup(SPI_NOR_DEBUGFS_ROOT, NULL);
 	if (!rootdir)
 		rootdir = debugfs_create_dir(SPI_NOR_DEBUGFS_ROOT, NULL);
 
@@ -247,3 +247,8 @@ void spi_nor_debugfs_register(struct spi_nor *nor)
 	debugfs_create_file("capabilities", 0444, d, nor,
 			    &spi_nor_capabilities_fops);
 }
+
+void spi_nor_debugfs_shutdown(void)
+{
+	debugfs_remove(rootdir);
+}