blkio: Introduce blkio controller cgroup interface

o This is basic implementation of blkio controller cgroup interface. This is
  the common interface visible to user space and should be used by different
  IO control policies as we implement those.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

2 files changed, 10 insertions, 0 deletions

diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index 9c8d31bacf46..ccefff02b6cb 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -60,3 +60,9 @@ SUBSYS(net_cls)
 #endif
 
 /* */
+
+#ifdef CONFIG_BLK_CGROUP
+SUBSYS(blkio)
+#endif
+
+/* */
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index eb73632440f1..d61b0b8b5cd1 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -68,6 +68,10 @@ struct io_context {
         unsigned short ioprio;
         unsigned short ioprio_changed;
 
+#ifdef CONFIG_BLK_CGROUP
+        unsigned short cgroup_changed;
+#endif
+
         /*
          * For request batching
          */