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>

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index c3f62654b6df4bee93cc69a86ca839031186f910..7baba40c1ed225f38921e2143514822080bc67ae 100644 (file)
--- 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);
        }