block: move blkcg initialization/destroy into disk allocation/release handler

blkcg works on FS bio level, so it is reasonable to make both blkcg and
gendisk sharing same lifetime. Meantime there won't be any FS IO when
releasing disk, so safe to move blkcg initialization/destroy into disk
allocation/release handler

Long term, we can move blkcg into gendisk completely.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/block/blk-core.c b/block/blk-core.c
index 839b13f0703ecd6a685fbaf7b6027e1cc00609f6..26cc1f071f5c58ae3d88eff5465aff1e187bab8f 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -490,17 +490,12 @@ struct request_queue *blk_alloc_queue(int node_id, bool alloc_srcu)
                                PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
                goto fail_stats;
 
-       if (blkcg_init_queue(q))
-               goto fail_ref;
-
        blk_queue_dma_alignment(q, 511);
        blk_set_default_limits(&q->limits);
        q->nr_requests = BLKDEV_DEFAULT_RQ;
 
        return q;
 
-fail_ref:
-       percpu_ref_exit(&q->q_usage_counter);
 fail_stats:
        blk_free_queue_stats(q->stats);
 fail_split:

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 241ded62f458ff3a2dd520a88110c2e76122cb07..220085109d7f0076a580ca125c46e606d6d91dd2 100644 (file)
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -751,13 +751,6 @@ static void blk_exit_queue(struct request_queue *q)
                ioc_clear_queue(q);
                elevator_exit(q);
        }
-
-       /*
-        * Remove all references to @q from the block cgroup controller before
-        * restoring @q->queue_lock to avoid that restoring this pointer causes
-        * e.g. blkcg_print_blkgs() to crash.
-        */
-       blkcg_exit_queue(q);
 }
 
 /**

diff --git a/block/genhd.c b/block/genhd.c
index 11c761afd64fa37eaec4ff5fd83f28f0c44cf80e..9fc3ce7e563c16936c3e03e9e4ae13e1d20e9dea 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1134,9 +1134,12 @@ static void disk_release(struct device *dev)
 
        blk_mq_cancel_work_sync(disk->queue);
 
+       blkcg_exit_queue(disk->queue);
+
        disk_release_events(disk);
        kfree(disk->random);
        xa_destroy(&disk->part_tbl);
+
        disk->queue->disk = NULL;
        blk_put_queue(disk->queue);
 
@@ -1342,6 +1345,9 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
        if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
                goto out_destroy_part_tbl;
 
+       if (blkcg_init_queue(q))
+               goto out_erase_part0;
+
        rand_initialize_disk(disk);
        disk_to_dev(disk)->class = &block_class;
        disk_to_dev(disk)->type = &disk_type;
@@ -1354,6 +1360,8 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 #endif
        return disk;
 
+out_erase_part0:
+       xa_erase(&disk->part_tbl, 0);
 out_destroy_part_tbl:
        xa_destroy(&disk->part_tbl);
        disk->part0->bd_disk = NULL;