blkcg: add blkio_policy_ops operations for exit and stat reset

Add blkio_policy_ops->blkio_exit_group_fn() and
->blkio_reset_group_stats_fn().  These will be used to further
modularize blkcg policy implementation.

Signed-off-by: Tejun Heo <tj@kernel.org>

2 files changed, 16 insertions, 4 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 19ee29f1b7c5..2e6fb7d91805 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -131,12 +131,17 @@ static void blkg_free(struct blkio_group *blkg)
                 return;
 
         for (i = 0; i < BLKIO_NR_POLICIES; i++) {
+                struct blkio_policy_type *pol = blkio_policy[i];
                 struct blkg_policy_data *pd = blkg->pd[i];
 
-                if (pd) {
-                        free_percpu(pd->stats_cpu);
-                        kfree(pd);
-                }
+                if (!pd)
+                        continue;
+
+                if (pol && pol->ops.blkio_exit_group_fn)
+                        pol->ops.blkio_exit_group_fn(blkg);
+
+                free_percpu(pd->stats_cpu);
+                kfree(pd);
         }
 
         kfree(blkg);
@@ -432,6 +437,9 @@ blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
                         blkg_stat_reset(&stats->empty_time);
 #endif
                         blkio_reset_stats_cpu(blkg, pol->plid);
+
+                        if (pol->ops.blkio_reset_group_stats_fn)
+                                pol->ops.blkio_reset_group_stats_fn(blkg);
                 }
         }
 
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index c82de47ae69f..d0ee649e8bbb 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -153,9 +153,13 @@ struct blkio_group {
 };
 
 typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
+typedef void (blkio_exit_group_fn)(struct blkio_group *blkg);
+typedef void (blkio_reset_group_stats_fn)(struct blkio_group *blkg);
 
 struct blkio_policy_ops {
         blkio_init_group_fn *blkio_init_group_fn;
+        blkio_exit_group_fn *blkio_exit_group_fn;
+        blkio_reset_group_stats_fn *blkio_reset_group_stats_fn;
 };
 
 struct blkio_policy_type {