linux-kernel - [PATCH] mtd: core: Fix refcounting for unpartitioned MTDs

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Date:   Sun,  6 Dec 2020 21:22:20 +0100
From:   Richard Weinberger <richard@....at>
To:     miquel.raynal@...tlin.com
Cc:     vigneshr@...com, linux-mtd@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Richard Weinberger <richard@....at>,
        stable@...r.kernel.org
Subject: [PATCH] mtd: core: Fix refcounting for unpartitioned MTDs

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

Cc: stable@...r.kernel.org
Fixes: 46b5889cc2c5 ("mtd: implement proper partition handling")
Signed-off-by: Richard Weinberger <richard@....at>
---
 drivers/mtd/mtdcore.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index e9e163ae9d86..b07cbb0661fb 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -993,6 +993,8 @@ int __get_mtd_device(struct mtd_info *mtd)
 		}
 	}
 
+	master->usecount++;
+
 	while (mtd->parent) {
 		mtd->usecount++;
 		mtd = mtd->parent;
@@ -1059,6 +1061,8 @@ void __put_mtd_device(struct mtd_info *mtd)
 		mtd = mtd->parent;
 	}
 
+	master->usecount--;
+
 	if (master->_put_device)
 		master->_put_device(master);
 
-- 
2.26.2