dm: prepare to support WRITE SAME
Allow targets to opt in to WRITE SAME support by setting
'num_write_same_requests' in the dm_target structure.
A dm device will only advertise WRITE SAME support if all its
targets and all its underlying devices support it.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 38d27a1..d1f6cd8 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -205,6 +205,11 @@
*/
unsigned num_discard_requests;
+ /*
+ * The number of WRITE SAME requests that will be submitted to the target.
+ */
+ unsigned num_write_same_requests;
+
/* target specific data */
void *private;