mtd: block2mtd: check device size

fixme applied : check device size is a multiple of erasesize.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/devices/block2mtd.c

@@ -209,7 +209,6 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
 }
 
 
-/* FIXME: ensure that mtd->size % erase_size == 0 */
 static struct block2mtd_dev *add_device(char *devname, int erase_size)
 {
 	const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
@@ -249,6 +248,11 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
 		goto err_free_block2mtd;
 	}
 
+	if ((long)dev->blkdev->bd_inode->i_size % erase_size) {
+		pr_err("erasesize must be a divisor of device size\n");
+		goto err_free_block2mtd;
+	}
+
 	mutex_init(&dev->write_mutex);
 
 	/* Setup the MTD structure */