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

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=e1d0fe3cddf2306e3ac32569aa152f1909c9b46e
Commit:     e1d0fe3cddf2306e3ac32569aa152f1909c9b46e
Parent:     24cc7b8a2a48a5707637e918a51ea547efe24892
Author:     Martin Krause <Martin.Krause at tqs.de>
AuthorDate: Tue Jun 22 15:00:19 2010 +0200
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Mon Aug 2 09:04:20 2010 +0100

    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 at tqs.de>
    Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/mtdconcat.c |   20 ++++++++++++--------
 1 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index 7e07562..4567bc3 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)