[PATCH] brd: fix uninitialized use of brd->dax_dev

[Gerald Schaefer]

commit 1647b9b9 "brd: add dax_operations support" introduced the allocation
and freeing of a dax_device, but the allocated dax_device is not stored
into the brd_device, so brd_del_one() will eventually operate on an
uninitialized brd->dax_dev.

Fix this by storing the allocated dax_device to brd->dax_dev.

Signed-off-by: Gerald Schaefer <gerald.schae...@de.ibm.com>
---
 drivers/block/brd.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 38f38df..57b574f 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -404,9 +404,7 @@ static struct brd_device *brd_alloc(int i)
 {
        struct brd_device *brd;
        struct gendisk *disk;
-#ifdef CONFIG_BLK_DEV_RAM_DAX
-       struct dax_device *dax_dev;
-#endif
+
        brd = kzalloc(sizeof(*brd), GFP_KERNEL);
        if (!brd)
                goto out;
@@ -443,8 +441,8 @@ static struct brd_device *brd_alloc(int i)
 
 #ifdef CONFIG_BLK_DEV_RAM_DAX
        queue_flag_set_unlocked(QUEUE_FLAG_DAX, brd->brd_queue);
-       dax_dev = alloc_dax(brd, disk->disk_name, &brd_dax_ops);
-       if (!dax_dev)
+       brd->dax_dev = alloc_dax(brd, disk->disk_name, &brd_dax_ops);
+       if (!brd->dax_dev)
                goto out_free_inode;
 #endif
 
@@ -453,8 +451,8 @@ static struct brd_device *brd_alloc(int i)
 
 #ifdef CONFIG_BLK_DEV_RAM_DAX
 out_free_inode:
-       kill_dax(dax_dev);
-       put_dax(dax_dev);
+       kill_dax(brd->dax_dev);
+       put_dax(brd->dax_dev);
 #endif
 out_free_queue:
        blk_cleanup_queue(brd->brd_queue);
-- 
2.10.2