Now that alloc_dax() returns ERR_PTR(-EOPNOTSUPP) rather than NULL,
the callers do not have to handle NULL return values anymore.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arch@vger.kernel.org
Cc: linux-cxl@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: dm-devel@lists.linux.dev
Cc: nvdimm@lists.linux.dev
---
 drivers/nvdimm/pmem.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index f1d9f5c6dbac..e9898457a7bd 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -558,8 +558,8 @@ static int pmem_attach_disk(struct device *dev,
 	disk->bb = &pmem->bb;
 
 	dax_dev = alloc_dax(pmem, &pmem_dax_ops);
-	if (IS_ERR_OR_NULL(dax_dev)) {
-		rc = IS_ERR(dax_dev) ? PTR_ERR(dax_dev) : -EOPNOTSUPP;
+	if (IS_ERR(dax_dev)) {
+		rc = PTR_ERR(dax_dev);
 		if (rc != -EOPNOTSUPP)
 			goto out;
 	} else {
-- 
2.39.2