Extend 'struct dm_target' to have dax_supported bit, which allows
dm-table to check if a dm-target supports DAX.
Change dm-linear to set this bit when its target physical device
supports DAX.
Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
Cc: Alasdair Kergon <agk@xxxxxxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
drivers/md/dm-linear.c | 2 ++
include/linux/device-mapper.h | 5 +++++
2 files changed, 7 insertions(+)
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 49bd7d2..6fdbbc8 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -59,6 +59,8 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
ti->num_flush_bios = 1;
ti->num_discard_bios = 1;
ti->num_write_same_bios = 1;
+ if (lc->dev->bdev->bd_disk->flags & GENHD_FL_DAX)
+ ti->dax_supported = 1;
ti->private = lc;
return 0;
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 16e6c8c..9b72989 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -290,6 +290,11 @@ struct dm_target {
* Set if this target does not return zeroes on discarded blocks.
*/
bool discard_zeroes_data_unsupported:1;
+
+ /*
+ * Set if the target supports DAX (direct access).
+ */
+ bool dax_supported:1;
};
/* Each target can link one of these into the table */
--
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