From: Martin Krause <Martin.Krause@tqs.de>
Date: Tue, 22 Jun 2010 13:00:19 +0000 (+0200)
Subject: mtd: mtdconcat: fix bug with uninitialized lock and unlock functions
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e1d0fe3cddf2306e3ac32569aa152f1909c9b46e;p=linux-beck.git

mtd: mtdconcat: fix bug with uninitialized lock and unlock functions

Test if a lock or unlock function is present (pointer not NULL) before
calling it, to prevent a kernel dump.

Artem: removed extra blank lines

Signed-off-by: Martin Krause <martin.krause@tqs.de>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---

diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index 7e075621bbf4..4567bc373780 100644
--- a/drivers/mtd/mtdconcat.c
+++ b/drivers/mtd/mtdconcat.c
@@ -540,10 +540,12 @@ static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 		else
 			size = len;
 
-		err = subdev->lock(subdev, ofs, size);
-
-		if (err)
-			break;
+		if (subdev->lock) {
+			err = subdev->lock(subdev, ofs, size);
+			if (err)
+				break;
+		} else
+			err = -EOPNOTSUPP;
 
 		len -= size;
 		if (len == 0)
@@ -578,10 +580,12 @@ static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 		else
 			size = len;
 
-		err = subdev->unlock(subdev, ofs, size);
-
-		if (err)
-			break;
+		if (subdev->unlock) {
+			err = subdev->unlock(subdev, ofs, size);
+			if (err)
+				break;
+		} else
+			err = -EOPNOTSUPP;
 
 		len -= size;
 		if (len == 0)