From d751939235b9b7bc4af15f90a3e99288a8b844a7 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 29 Nov 2021 11:21:35 +0100
Subject: [PATCH] dm: fix alloc_dax error handling in alloc_dev
Git-commit: d751939235b9b7bc4af15f90a3e99288a8b844a7
Patch-mainline: v5.17-rc1
References: git-fixes

Make sure ->dax_dev is NULL on error so that the cleanup path doesn't
trip over an ERR_PTR.

(Coly Li: rebased for Linux v5.14 based SUSE kernel)

Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211129102203.2243509-2-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Coly Li <colyli@suse.de>

---
 drivers/md/dm.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1791,8 +1791,10 @@ static struct mapped_device *alloc_dev(i
 	if (IS_ENABLED(CONFIG_DAX_DRIVER)) {
 		md->dax_dev = alloc_dax(md, md->disk->disk_name,
 					&dm_dax_ops, 0);
-		if (IS_ERR(md->dax_dev))
+		if (IS_ERR(md->dax_dev)) {
+			md->dax_dev = NULL;
 			goto bad;
+		}
 	}
 
 	add_disk_no_queue_reg(md->disk);