Reuse one union shared by elevator and flush request for data of
private request. Private request won't enter IO scheduler and never
be a flush request, so reuse the space for data of private request.
This field is added to pass driver private info for private request
only.
Cc: James Smart <james.smart@xxxxxxxxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
include/linux/blkdev.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6a4f7abbdcf7..ce708dc10bdc 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -177,7 +177,8 @@ struct request {
* Three pointers are available for the IO schedulers, if they need
* more they have to dynamically allocate it. Flush requests are
* never put on the IO scheduler. So let the flush fields share
- * space with the elevator data.
+ * space with the elevator data. Private request are never put on
+ * IO scheduler, and not be a flush request.
*/
union {
struct {
@@ -190,6 +191,9 @@ struct request {
struct list_head list;
rq_end_io_fn *saved_end_io;
} flush;
+
+ /* used for private request only */
+ unsigned long private_rq_data;
};
struct gendisk *rq_disk;
--
2.20.1
