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authorChristoph Hellwig <hch@lst.de>2023-02-03 16:03:44 +0100
committerJens Axboe <axboe@kernel.dk>2023-02-03 08:20:04 -0700
commit0b6f93bdf07e52620f725f721e547408e0d04c9d (patch)
treef3af6f21fa7ef66764f8fb9d9d69ecdf42bef90a /block/blk-cgroup.c
parent178fa7d49815ea8001f43ade37a22072829fd8ab (diff)
blk-cgroup: improve error unwinding in blkg_alloc
Unwind only the previous initialization steps that happened in blkg_alloc using goto based unwinding. This avoids the need for the !queue special case in blkg_free and thus ensures that any blkg seens outside of blkg_alloc is always fully constructed. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-cgroup.c')
-rw-r--r--block/blk-cgroup.c39
1 files changed, 19 insertions, 20 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index cb110fc51940..9df02a6d04d3 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -128,22 +128,16 @@ static void blkg_free_workfn(struct work_struct *work)
* blkcg_mutex is used to synchronize blkg_free_workfn() and
* blkcg_deactivate_policy().
*/
- if (q)
- mutex_lock(&q->blkcg_mutex);
-
+ mutex_lock(&q->blkcg_mutex);
for (i = 0; i < BLKCG_MAX_POLS; i++)
if (blkg->pd[i])
blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
-
if (blkg->parent)
blkg_put(blkg->parent);
+ list_del_init(&blkg->q_node);
+ mutex_unlock(&q->blkcg_mutex);
- if (q) {
- list_del_init(&blkg->q_node);
- mutex_unlock(&q->blkcg_mutex);
- blk_put_queue(q);
- }
-
+ blk_put_queue(q);
free_percpu(blkg->iostat_cpu);
percpu_ref_exit(&blkg->refcnt);
kfree(blkg);
@@ -265,16 +259,13 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct gendisk *disk,
blkg = kzalloc_node(sizeof(*blkg), gfp_mask, disk->queue->node);
if (!blkg)
return NULL;
-
if (percpu_ref_init(&blkg->refcnt, blkg_release, 0, gfp_mask))
- goto err_free;
-
+ goto out_free_blkg;
blkg->iostat_cpu = alloc_percpu_gfp(struct blkg_iostat_set, gfp_mask);
if (!blkg->iostat_cpu)
- goto err_free;
-
+ goto out_exit_refcnt;
if (!blk_get_queue(disk->queue))
- goto err_free;
+ goto out_free_iostat;
blkg->q = disk->queue;
INIT_LIST_HEAD(&blkg->q_node);
@@ -299,8 +290,7 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct gendisk *disk,
/* alloc per-policy data and attach it to blkg */
pd = pol->pd_alloc_fn(gfp_mask, disk->queue, blkcg);
if (!pd)
- goto err_free;
-
+ goto out_free_pds;
blkg->pd[i] = pd;
pd->blkg = blkg;
pd->plid = i;
@@ -309,8 +299,17 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct gendisk *disk,
return blkg;
-err_free:
- blkg_free(blkg);
+out_free_pds:
+ while (--i >= 0)
+ if (blkg->pd[i])
+ blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
+ blk_put_queue(disk->queue);
+out_free_iostat:
+ free_percpu(blkg->iostat_cpu);
+out_exit_refcnt:
+ percpu_ref_exit(&blkg->refcnt);
+out_free_blkg:
+ kfree(blkg);
return NULL;
}