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 <[email protected]> Cc: Alasdair Kergon <[email protected]> Cc: Mike Snitzer <[email protected]> Cc: Dan Williams <[email protected]> Cc: Ross Zwisler <[email protected]> --- 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 */
