Re: [PATCH V2 1/2] blk-mq: add callback of .cleanup_rq

On 7/19/19 8:06 PM, Ming Lei wrote:

diff --git a/block/blk-mq.c b/block/blk-mq.c index b038ec680e84..fc38d95c557f 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -502,6 +502,9 @@ void blk_mq_free_request(struct request *rq) struct blk_mq_ctx *ctx = rq->mq_ctx; struct blk_mq_hw_ctx *hctx = rq->mq_hctx;

• if (q->mq_ops->cleanup_rq)

• q->mq_ops->cleanup_rq(rq);
  

• if (rq->rq_flags & RQF_ELVPRIV) { if (e && e->type->ops.finish_request) e->type->ops.finish_request(rq);

I'm concerned about the performance impact of this change. How about not introducing .cleanup_rq() and adding a call to scsi_mq_uninit_cmd() in scsi_queue_rq() just before that function returns BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE?

Thanks,

Bart.