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authorJan Kara <jack@suse.cz>2020-09-20 18:54:42 +0300
committerDan Williams <dan.j.williams@intel.com>2020-09-20 18:55:09 +0300
commite2ec5128254518cae320d5dc631b71b94160f663 (patch)
tree1127fbd05a2269d92dff9896b3e59086be65863f /drivers/dax/super.c
parent02186d8897d49b0afd3c80b6cf23437d91024065 (diff)
downloadlinux-e2ec5128254518cae320d5dc631b71b94160f663.tar.xz
dm: Call proper helper to determine dax support
DM was calling generic_fsdax_supported() to determine whether a device referenced in the DM table supports DAX. However this is a helper for "leaf" device drivers so that they don't have to duplicate common generic checks. High level code should call dax_supported() helper which that calls into appropriate helper for the particular device. This problem manifested itself as kernel messages: dm-3: error: dax access failed (-95) when lvm2-testsuite run in cases where a DM device was stacked on top of another DM device. Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices") Cc: <stable@vger.kernel.org> Tested-by: Adrian Huang <ahuang12@lenovo.com> Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Mike Snitzer <snitzer@redhat.com> Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/r/160061715195.13131.5503173247632041975.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dax/super.c')
-rw-r--r--drivers/dax/super.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index e5767c83ea23..b6284c5cae0a 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -325,11 +325,15 @@ EXPORT_SYMBOL_GPL(dax_direct_access);
bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len)
{
+ if (!dax_dev)
+ return false;
+
if (!dax_alive(dax_dev))
return false;
return dax_dev->ops->dax_supported(dax_dev, bdev, blocksize, start, len);
}
+EXPORT_SYMBOL_GPL(dax_supported);
size_t dax_copy_from_iter(struct dax_device *dax_dev, pgoff_t pgoff, void *addr,
size_t bytes, struct iov_iter *i)