mtd: fix 'part' field data corruption in mtd_info

[ Upstream commit 37c5f9e80e015d0df17d0c377c18523002986851 ]

Commit 46b5889cc2c5 ("mtd: implement proper partition handling")
started using "mtd_get_master_ofs()" in mtd callbacks to determine
memory offsets by means of 'part' field from mtd_info, what previously
was smashed accessing 'master' field in the mtd_set_dev_defaults() method.
That provides wrong offset what causes hardware access errors.

Just make 'part', 'master' as separate fields, rather than using
union type to avoid 'part' data corruption when mtd_set_dev_defaults()
is called.

Fixes: 46b5889cc2c5 ("mtd: implement proper partition handling")
Signed-off-by: Oleksandr Ocheretnyi <oocheret@cisco.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220417184649.449289-1-oocheret@cisco.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 88227044fc86c997f0a36be061546a23ed2ee9cb..8a2c60235ebb857d416dd79b19fb78565a0e58c8 100644 (file)
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -394,10 +394,8 @@ struct mtd_info {
        /* List of partitions attached to this MTD device */
        struct list_head partitions;
 
-       union {
-               struct mtd_part part;
-               struct mtd_master master;
-       };
+       struct mtd_part part;
+       struct mtd_master master;
 };
 
 static inline struct mtd_info *mtd_get_master(struct mtd_info *mtd)