[PATCH v5 2/8] nvdimm/pmem: Treat alloc_dax() -EOPNOTSUPP failure as non-fatal

[Mathieu Desnoyers]

In preparation for checking whether the architecture has data cache
aliasing within alloc_dax(), modify the error handling of nvdimm/pmem
pmem_attach_disk() to treat alloc_dax() -EOPNOTSUPP failure as non-fatal.

[ Based on commit "nvdimm/pmem: Fix leak on dax_add_host() failure". ]

Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing 
caches")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
Reviewed-by: Dan Williams <dan.j.willi...@intel.com>
Cc: Alasdair Kergon <a...@redhat.com>
Cc: Mike Snitzer <snit...@kernel.org>
Cc: Mikulas Patocka <mpato...@redhat.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Dan Williams <dan.j.willi...@intel.com>
Cc: Vishal Verma <vishal.l.ve...@intel.com>
Cc: Dave Jiang <dave.ji...@intel.com>
Cc: Matthew Wilcox <wi...@infradead.org>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Russell King <li...@armlinux.org.uk>
Cc: linux-a...@vger.kernel.org
Cc: linux-...@vger.kernel.org
Cc: linux-fsde...@vger.kernel.org
Cc: linux...@kvack.org
Cc: linux-...@vger.kernel.org
Cc: dm-devel@lists.linux.dev
Cc: nvd...@lists.linux.dev
---
 drivers/nvdimm/pmem.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 9fe358090720..e9898457a7bd 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -560,17 +560,19 @@ static int pmem_attach_disk(struct device *dev,
        dax_dev = alloc_dax(pmem, &pmem_dax_ops);
        if (IS_ERR(dax_dev)) {
                rc = PTR_ERR(dax_dev);
-               goto out;
+               if (rc != -EOPNOTSUPP)
+                       goto out;
+       } else {
+               set_dax_nocache(dax_dev);
+               set_dax_nomc(dax_dev);
+               if (is_nvdimm_sync(nd_region))
+                       set_dax_synchronous(dax_dev);
+               pmem->dax_dev = dax_dev;
+               rc = dax_add_host(dax_dev, disk);
+               if (rc)
+                       goto out_cleanup_dax;
+               dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
        }
-       set_dax_nocache(dax_dev);
-       set_dax_nomc(dax_dev);
-       if (is_nvdimm_sync(nd_region))
-               set_dax_synchronous(dax_dev);
-       pmem->dax_dev = dax_dev;
-       rc = dax_add_host(dax_dev, disk);
-       if (rc)
-               goto out_cleanup_dax;
-       dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
        rc = device_add_disk(dev, disk, pmem_attribute_groups);
        if (rc)
                goto out_remove_host;
-- 
2.39.2