blkcg: replace blkcg_policy->cpd_size with ->cpd_alloc/free_fn() methods
Each active policy has a cpd (blkcg_policy_data) on each blkcg. The
cpd's were allocated by blkcg core and each policy could request to
allocate extra space at the end by setting blkcg_policy->cpd_size
larger than the size of cpd.
This is a bit unusual but blkg (blkcg_gq) policy data used to be
handled this way too so it made sense to be consistent; however, blkg
policy data switched to alloc/free callbacks.
This patch makes similar changes to cpd handling.
blkcg_policy->cpd_alloc/free_fn() are added to replace ->cpd_size. As
cpd allocation is now done from policy side, it can simply allocate a
larger area which embeds cpd at the beginning.
As ->cpd_alloc_fn() may be able to perform all necessary
initializations, this patch makes ->cpd_init_fn() optional.
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>
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 247c42c..2b4354b 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -817,11 +817,15 @@
int i;
mutex_lock(&blkcg_pol_mutex);
+
list_del(&blkcg->all_blkcgs_node);
- mutex_unlock(&blkcg_pol_mutex);
for (i = 0; i < BLKCG_MAX_POLS; i++)
- kfree(blkcg->cpd[i]);
+ if (blkcg->cpd[i])
+ blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]);
+
+ mutex_unlock(&blkcg_pol_mutex);
+
kfree(blkcg);
}
@@ -854,11 +858,10 @@
* check if the policy requires any specific per-cgroup
* data: if it does, allocate and initialize it.
*/
- if (!pol || !pol->cpd_size)
+ if (!pol || !pol->cpd_alloc_fn)
continue;
- BUG_ON(blkcg->cpd[i]);
- cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
+ cpd = pol->cpd_alloc_fn(GFP_KERNEL);
if (!cpd) {
ret = ERR_PTR(-ENOMEM);
goto free_pd_blkcg;
@@ -866,7 +869,8 @@
blkcg->cpd[i] = cpd;
cpd->blkcg = blkcg;
cpd->plid = i;
- pol->cpd_init_fn(cpd);
+ if (pol->cpd_init_fn)
+ pol->cpd_init_fn(cpd);
}
spin_lock_init(&blkcg->lock);
@@ -882,7 +886,8 @@
free_pd_blkcg:
for (i--; i >= 0; i--)
- kfree(blkcg->cpd[i]);
+ if (blkcg->cpd[i])
+ blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]);
free_blkcg:
kfree(blkcg);
mutex_unlock(&blkcg_pol_mutex);
@@ -1159,11 +1164,11 @@
blkcg_policy[pol->plid] = pol;
/* allocate and install cpd's */
- if (pol->cpd_size) {
+ if (pol->cpd_alloc_fn) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
struct blkcg_policy_data *cpd;
- cpd = kzalloc(pol->cpd_size, GFP_KERNEL);
+ cpd = pol->cpd_alloc_fn(GFP_KERNEL);
if (!cpd) {
mutex_unlock(&blkcg_pol_mutex);
goto err_free_cpds;
@@ -1186,10 +1191,12 @@
return 0;
err_free_cpds:
- if (pol->cpd_size) {
+ if (pol->cpd_alloc_fn) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
- kfree(blkcg->cpd[pol->plid]);
- blkcg->cpd[pol->plid] = NULL;
+ if (blkcg->cpd[pol->plid]) {
+ pol->cpd_free_fn(blkcg->cpd[pol->plid]);
+ blkcg->cpd[pol->plid] = NULL;
+ }
}
}
blkcg_policy[pol->plid] = NULL;
@@ -1222,10 +1229,12 @@
/* remove cpds and unregister */
mutex_lock(&blkcg_pol_mutex);
- if (pol->cpd_size) {
+ if (pol->cpd_alloc_fn) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
- kfree(blkcg->cpd[pol->plid]);
- blkcg->cpd[pol->plid] = NULL;
+ if (blkcg->cpd[pol->plid]) {
+ pol->cpd_free_fn(blkcg->cpd[pol->plid]);
+ blkcg->cpd[pol->plid] = NULL;
+ }
}
}
blkcg_policy[pol->plid] = NULL;
