commit 814376483e7d85b69a70634633f1f9d01c6ee0cf
author Tejun Heo <tj@kernel.org> Tue Aug 18 14:55:15 2015 -0700
committer Jens Axboe <axboe@fb.com> Tue Aug 18 15:49:17 2015 -0700
tree 04d6f2749e947f348a184e75e7bf1bea9ff7d163
parent a9520cd6f2ac1fbbf206b915946534c6dddbaae2

blkcg: minor updates around blkcg_policy_data

* Rename blkcg->pd[] to blkcg->cpd[] so that cpd is consistently used
  for blkcg_policy_data.

* Make blkcg_policy->cpd_init_fn() take blkcg_policy_data instead of
  blkcg.  This makes it consistent with blkg_policy_data methods and
  to-be-added cpd alloc/free methods.

* blkcg_policy_data->blkcg and cpd_to_blkcg() added so that
  cpd_init_fn() can determine the associated blkcg from
  blkcg_policy_data.

v2: blkcg_policy_data->blkcg initializations were missing.  Added.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/blk-cgroup.c

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 8343450..247c42c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -821,7 +821,7 @@
 	mutex_unlock(&blkcg_pol_mutex);
 
 	for (i = 0; i < BLKCG_MAX_POLS; i++)
-		kfree(blkcg->pd[i]);
+		kfree(blkcg->cpd[i]);
 	kfree(blkcg);
 }
 
@@ -857,15 +857,16 @@
 		if (!pol || !pol->cpd_size)
 			continue;
 
-		BUG_ON(blkcg->pd[i]);
+		BUG_ON(blkcg->cpd[i]);
 		cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
 		if (!cpd) {
 			ret = ERR_PTR(-ENOMEM);
 			goto free_pd_blkcg;
 		}
-		blkcg->pd[i] = cpd;
+		blkcg->cpd[i] = cpd;
+		cpd->blkcg = blkcg;
 		cpd->plid = i;
-		pol->cpd_init_fn(blkcg);
+		pol->cpd_init_fn(cpd);
 	}
 
 	spin_lock_init(&blkcg->lock);
@@ -881,7 +882,7 @@
 
 free_pd_blkcg:
 	for (i--; i >= 0; i--)
-		kfree(blkcg->pd[i]);
+		kfree(blkcg->cpd[i]);
 free_blkcg:
 	kfree(blkcg);
 	mutex_unlock(&blkcg_pol_mutex);
@@ -1168,9 +1169,10 @@
 				goto err_free_cpds;
 			}
 
-			blkcg->pd[pol->plid] = cpd;
+			blkcg->cpd[pol->plid] = cpd;
+			cpd->blkcg = blkcg;
 			cpd->plid = pol->plid;
-			pol->cpd_init_fn(blkcg);
+			pol->cpd_init_fn(cpd);
 		}
 	}
 
@@ -1186,8 +1188,8 @@
 err_free_cpds:
 	if (pol->cpd_size) {
 		list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
-			kfree(blkcg->pd[pol->plid]);
-			blkcg->pd[pol->plid] = NULL;
+			kfree(blkcg->cpd[pol->plid]);
+			blkcg->cpd[pol->plid] = NULL;
 		}
 	}
 	blkcg_policy[pol->plid] = NULL;
@@ -1222,8 +1224,8 @@
 
 	if (pol->cpd_size) {
 		list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
-			kfree(blkcg->pd[pol->plid]);
-			blkcg->pd[pol->plid] = NULL;
+			kfree(blkcg->cpd[pol->plid]);
+			blkcg->cpd[pol->plid] = NULL;
 		}
 	}
 	blkcg_policy[pol->plid] = NULL;