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

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Message-Id: <20201228125052.887156137@linuxfoundation.org>
Date:   Mon, 28 Dec 2020 13:51:04 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Richard Weinberger <richard@....at>,
        Miquel Raynal <miquel.raynal@...tlin.com>
Subject: [PATCH 5.10 666/717] mtd: core: Fix refcounting for unpartitioned MTDs

From: Richard Weinberger <richard@....at>

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@...r.kernel.org
Fixes: 46b5889cc2c5 ("mtd: implement proper partition handling")
Signed-off-by: Richard Weinberger <richard@....at>
Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
Link: https://lore.kernel.org/linux-mtd/20201206202220.27290-1-richard@nod.at
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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);