mtd: blkdevs: do not forget to get MTD devices

Nowadays MTD devices have to be "get" before they can be
used. This has to be done with 'get_mtd_device()'. The
'blktrans_open()' function did not do this and instead
used 'try_module_get()'. Fix this.

Since 'get_mtd_device()' already gets the module, extra
'try_module_get()' is not needed.

This fixes oops when one tries to use mtdblock on top of
gluebi.

Reported-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index c3f62654b6df..7baba40c1ed2 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -144,7 +144,7 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
         struct mtd_blktrans_ops *tr = dev->tr;
         int ret = -ENODEV;
 
-        if (!try_module_get(dev->mtd->owner))
+        if (!get_mtd_device(NULL, dev->mtd->index))
                 goto out;
 
         if (!try_module_get(tr->owner))
@@ -158,7 +158,7 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
         ret = 0;
         if (tr->open && (ret = tr->open(dev))) {
                 dev->mtd->usecount--;
-                module_put(dev->mtd->owner);
+                put_mtd_device(dev->mtd);
         out_tr:
                 module_put(tr->owner);
         }
@@ -177,7 +177,7 @@ static int blktrans_release(struct gendisk *disk, fmode_t mode)
 
         if (!ret) {
                 dev->mtd->usecount--;
-                module_put(dev->mtd->owner);
+                put_mtd_device(dev->mtd);
                 module_put(tr->owner);
         }