From: Boris Brezillon <boris.brezillon@free-electrons.com>
Date: Fri, 15 Dec 2017 12:39:51 +0000 (+0100)
Subject: mtd: Do not allow MTD devices with inconsistent erase properties
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=33f45c44d68b3593826524ba6d02bd9cce9e101e;p=openwrt%2Fstaging%2Fblogic.git

mtd: Do not allow MTD devices with inconsistent erase properties

When mtd->erasesize is 0 or mtd->_erase is NULL, that means the device
does not support the erase operation, which in turn means it should
have the MTD_NO_ERASE flag set.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Miquel Raynal <miquel.raynal@free-electrons.com>
---

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index f80e911b8843..642c35dde686 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -503,6 +503,11 @@ int add_mtd_device(struct mtd_info *mtd)
 		return -EEXIST;
 
 	BUG_ON(mtd->writesize == 0);
+
+	if (WARN_ON((!mtd->erasesize || !mtd->_erase) &&
+		    !(mtd->flags & MTD_NO_ERASE)))
+		return -EINVAL;
+
 	mutex_lock(&mtd_table_mutex);
 
 	i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);