UBI: block: fix dereference on uninitialized dev

commit 4df38926f337 ("UBI: block: Avoid disk size integer overflow")
introduced a dereference on dev (which is not initialized at that
point) when printing a warning message.  Re-order disk_capacity check
after the dev is found.

Found by cppcheck:
 [drivers/mtd/ubi/block.c:509]: (error) Uninitialized variable: dev

Artem: tweak the error message a bit

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 33c64955d4d7..518792b7634d 100644
--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -504,11 +504,6 @@ static int ubiblock_resize(struct ubi_volume_info *vi)
         struct ubiblock *dev;
         u64 disk_capacity = ((u64)vi->size * vi->usable_leb_size) >> 9;
 
-        if ((sector_t)disk_capacity != disk_capacity) {
-                ubi_warn("%s: the volume is too big, cannot resize (%d LEBs)",
-                         dev->gd->disk_name, vi->size);
-                return -EFBIG;
-        }
         /*
          * Need to lock the device list until we stop using the device,
          * otherwise the device struct might get released in
@@ -520,6 +515,12 @@ static int ubiblock_resize(struct ubi_volume_info *vi)
                 mutex_unlock(&devices_mutex);
                 return -ENODEV;
         }
+        if ((sector_t)disk_capacity != disk_capacity) {
+                mutex_unlock(&devices_mutex);
+                ubi_warn("%s: the volume is too big (%d LEBs), cannot resize",
+                         dev->gd->disk_name, vi->size);
+                return -EFBIG;
+        }
 
         mutex_lock(&dev->dev_mutex);
         set_capacity(dev->gd, disk_capacity);