[PATCH 5.10 666/717] mtd: core: Fix refcounting for unpartitioned MTDs

[Greg Kroah-Hartman]

From: Richard Weinberger <richard@xxxxxx>

commit 1ca71415f075353974524e96ed175306d8a937a8 upstream.

Apply changes to usecount also to the master partition.
Otherwise we have no refcounting at all if an MTD has no partitions.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 46b5889cc2c5 ("mtd: implement proper partition handling")
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Link: https://lore.kernel.org/linux-mtd/20201206202220.27290-1-richard@xxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mtd/mtdcore.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -993,6 +993,8 @@ int __get_mtd_device(struct mtd_info *mt
 		}
 	}
 
+	master->usecount++;
+
 	while (mtd->parent) {
 		mtd->usecount++;
 		mtd = mtd->parent;
@@ -1059,6 +1061,8 @@ void __put_mtd_device(struct mtd_info *m
 		mtd = mtd->parent;
 	}
 
+	master->usecount--;
+
 	if (master->_put_device)
 		master->_put_device(master);