From: Huaisheng Ye <yehs1@lenovo.com>
Date: Mon, 30 Jul 2018 15:15:46 +0800
Subject: dax/super: Do not request a pointer kaddr when not required
Git-commit: e0b401e3fef0f81fd87434793db1adb0d7568058
Patch-mainline: v4.19-rc1
References: FATE#326060

Function __bdev_dax_supported doesn't need to get local pointer kaddr
from direct_access. Using NULL instead of having to pass in a useless
local pointer that caller then just throw away.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/dax/super.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -89,7 +89,6 @@ bool __bdev_dax_supported(struct block_d
 	pgoff_t pgoff;
 	struct request_queue *q;
 	int err, id;
-	void *kaddr;
 	pfn_t pfn;
 	long len;
 	char buf[BDEVNAME_SIZE];
@@ -122,7 +121,7 @@ bool __bdev_dax_supported(struct block_d
 	}
 
 	id = dax_read_lock();
-	len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
+	len = dax_direct_access(dax_dev, pgoff, 1, NULL, &pfn);
 	dax_read_unlock(id);
 
 	put_dax(dax_dev);