* blkg_alloc - allocate a blkg
* @blkcg: block cgroup the new blkg is associated with
* @q: request_queue the new blkg is associated with
+ * @gfp_mask: allocation mask to use
*
* Allocate a new blkg assocating @blkcg and @q.
*/
-static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q)
+static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
+ gfp_t gfp_mask)
{
struct blkcg_gq *blkg;
int i;
/* alloc and init base part */
- blkg = kzalloc_node(sizeof(*blkg), GFP_ATOMIC, q->node);
+ blkg = kzalloc_node(sizeof(*blkg), gfp_mask, q->node);
if (!blkg)
return NULL;
continue;
/* alloc per-policy data and attach it to blkg */
- pd = kzalloc_node(pol->pd_size, GFP_ATOMIC, q->node);
+ pd = kzalloc_node(pol->pd_size, gfp_mask, q->node);
if (!pd) {
blkg_free(blkg);
return NULL;
blkg->pd[i] = pd;
pd->blkg = blkg;
- }
-
- /* invoke per-policy init */
- for (i = 0; i < BLKCG_MAX_POLS; i++) {
- struct blkcg_policy *pol = blkcg_policy[i];
+ /* invoke per-policy init */
if (blkcg_policy_enabled(blkg->q, pol))
pol->pd_init_fn(blkg);
}
}
EXPORT_SYMBOL_GPL(blkg_lookup);
+/*
+ * If @new_blkg is %NULL, this function tries to allocate a new one as
+ * necessary using %GFP_ATOMIC. @new_blkg is always consumed on return.
+ */
static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
- struct request_queue *q)
- __releases(q->queue_lock) __acquires(q->queue_lock)
+ struct request_queue *q,
+ struct blkcg_gq *new_blkg)
{
struct blkcg_gq *blkg;
int ret;
blkg = __blkg_lookup(blkcg, q);
if (blkg) {
rcu_assign_pointer(blkcg->blkg_hint, blkg);
- return blkg;
+ goto out_free;
}
/* blkg holds a reference to blkcg */
- if (!css_tryget(&blkcg->css))
- return ERR_PTR(-EINVAL);
+ if (!css_tryget(&blkcg->css)) {
+ blkg = ERR_PTR(-EINVAL);
+ goto out_free;
+ }
/* allocate */
- ret = -ENOMEM;
- blkg = blkg_alloc(blkcg, q);
- if (unlikely(!blkg))
- goto err_put;
+ if (!new_blkg) {
+ new_blkg = blkg_alloc(blkcg, q, GFP_ATOMIC);
+ if (unlikely(!new_blkg)) {
+ blkg = ERR_PTR(-ENOMEM);
+ goto out_put;
+ }
+ }
+ blkg = new_blkg;
/* insert */
- ret = radix_tree_preload(GFP_ATOMIC);
- if (ret)
- goto err_free;
-
spin_lock(&blkcg->lock);
ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg);
if (likely(!ret)) {
}
spin_unlock(&blkcg->lock);
- radix_tree_preload_end();
-
if (!ret)
return blkg;
-err_free:
- blkg_free(blkg);
-err_put:
+
+ blkg = ERR_PTR(ret);
+out_put:
css_put(&blkcg->css);
- return ERR_PTR(ret);
+out_free:
+ blkg_free(new_blkg);
+ return blkg;
}
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
*/
if (unlikely(blk_queue_bypass(q)))
return ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);
- return __blkg_lookup_create(blkcg, q);
+ return __blkg_lookup_create(blkcg, q, NULL);
}
EXPORT_SYMBOL_GPL(blkg_lookup_create);
static void blkg_destroy(struct blkcg_gq *blkg)
{
- struct request_queue *q = blkg->q;
struct blkcg *blkcg = blkg->blkcg;
- lockdep_assert_held(q->queue_lock);
+ lockdep_assert_held(blkg->q->queue_lock);
lockdep_assert_held(&blkcg->lock);
/* Something wrong if we are trying to remove same group twice */
struct blkcg_gq *blkg;
struct blkg_policy_data *pd, *n;
int cnt = 0, ret;
+ bool preloaded;
if (blkcg_policy_enabled(q, pol))
return 0;
+ /* preallocations for root blkg */
+ blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
+ if (!blkg)
+ return -ENOMEM;
+
+ preloaded = !radix_tree_preload(GFP_KERNEL);
+
blk_queue_bypass_start(q);
/* make sure the root blkg exists and count the existing blkgs */
spin_lock_irq(q->queue_lock);
rcu_read_lock();
- blkg = __blkg_lookup_create(&blkcg_root, q);
+ blkg = __blkg_lookup_create(&blkcg_root, q, blkg);
rcu_read_unlock();
+ if (preloaded)
+ radix_tree_preload_end();
+
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
goto out_unlock;