Commit aba19ee7 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: Move flush queue allocation into blk_mq_init_hctx() 



Move flush queue allocation into blk_mq_init_hctx() and its release into
blk_mq_exit_hctx(), and prepare for replacing tags->lock with SRCU to
draining inflight request walking. blk_mq_exit_hctx() is the last chance
for us to get valid `tag_set` reference, and we need to add one SRCU to
`tag_set` for freeing flush request via call_srcu().

It is safe to move flush queue & request release into blk_mq_exit_hctx(),
because blk_mq_clear_flush_rq_mapping() clears the flush request
reference int driver tags inflight request table, meantime inflight
request walking is drained.

Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ba28afbd

block/blk-mq-sysfs.c

+0 −1
Original line number Diff line number Diff line
@@ -34,7 +34,6 @@ static void blk_mq_hw_sysfs_release(struct kobject *kobj) 
	struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,

						  kobj);



	blk_free_flush_queue(hctx->fq);

	sbitmap_free(&hctx->ctx_map);

	free_cpumask_var(hctx->cpumask);

	kfree(hctx->ctxs);

block/blk-mq.c

+13 −7
Original line number Diff line number Diff line
@@ -3939,6 +3939,9 @@ static void blk_mq_exit_hctx(struct request_queue *q, 
	if (set->ops->exit_hctx)

		set->ops->exit_hctx(hctx, hctx_idx);



	blk_free_flush_queue(hctx->fq);

	hctx->fq = NULL;



	xa_erase(&q->hctx_table, hctx_idx);



	spin_lock(&q->unused_hctx_lock);
@@ -3964,13 +3967,19 @@ static int blk_mq_init_hctx(struct request_queue *q, 
		struct blk_mq_tag_set *set,

		struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)

{

	gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;



	hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);

	if (!hctx->fq)

		goto fail;



	hctx->queue_num = hctx_idx;



	hctx->tags = set->tags[hctx_idx];



	if (set->ops->init_hctx &&

	    set->ops->init_hctx(hctx, set->driver_data, hctx_idx))

		goto fail;

		goto fail_free_fq;



	if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,

				hctx->numa_node))
@@ -3987,6 +3996,9 @@ static int blk_mq_init_hctx(struct request_queue *q, 
 exit_hctx:

	if (set->ops->exit_hctx)

		set->ops->exit_hctx(hctx, hctx_idx);

 fail_free_fq:

	blk_free_flush_queue(hctx->fq);

	hctx->fq = NULL;

 fail:

	return -1;

}
@@ -4038,16 +4050,10 @@ blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set, 
	init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);

	INIT_LIST_HEAD(&hctx->dispatch_wait.entry);



	hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);

	if (!hctx->fq)

		goto free_bitmap;



	blk_mq_hctx_kobj_init(hctx);



	return hctx;



 free_bitmap:

	sbitmap_free(&hctx->ctx_map);

 free_ctxs:

	kfree(hctx->ctxs);

 free_cpumask: