diff options
authorColy Li <colyli@suse.de>2020-09-04 00:16:25 +0800
committerVishal Verma <vishal.l.verma@intel.com>2020-09-03 12:28:03 -0600
commit6180bb446ab624b9ab8bf201ed251ca87f07b413 (patch)
parentc2affe920b0e0669650943ac086215cf6519be34 (diff)
dax: fix detection of dax support for non-persistent memory block devices
When calling __generic_fsdax_supported(), a dax-unsupported device may not have dax_dev as NULL, e.g. the dax related code block is not enabled by Kconfig. Therefore in __generic_fsdax_supported(), to check whether a device supports DAX or not, the following order of operations should be performed: - If dax_dev pointer is NULL, it means the device driver explicitly announce it doesn't support DAX. Then it is OK to directly return false from __generic_fsdax_supported(). - If dax_dev pointer is NOT NULL, it might be because the driver doesn't support DAX and not explicitly initialize related data structure. Then bdev_dax_supported() should be called for further check. If device driver desn't explicitly set its dax_dev pointer to NULL, this is not a bug. Calling bdev_dax_supported() makes sure they can be recognized as dax-unsupported eventually. Fixes: c2affe920b0e ("dax: do not print error message for non-persistent memory block device") Cc: Jan Kara <jack@suse.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Reviewed-and-tested-by: Adrian Huang <ahuang12@lenovo.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Signed-off-by: Coly Li <colyli@suse.de> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Link: https://lore.kernel.org/r/20200903161625.19524-1-colyli@suse.de
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 32642634c1bb..e5767c83ea23 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -100,7 +100,7 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
return false;
- if (!dax_dev && !bdev_dax_supported(bdev, blocksize)) {
+ if (!dax_dev || !bdev_dax_supported(bdev, blocksize)) {
pr_debug("%s: error: dax unsupported by block device\n",
bdevname(bdev, buf));
return false;