Re: [PATCH 1/2] scsi_host: add support for request batching

From: Paolo Bonzini
Date: Mon Jun 03 2019 - 04:20:11 EST


On 31/05/19 05:27, Ming Lei wrote:
> It should be fine to implement scsi_commit_rqs() as:
>
> if (shost->hostt->commit_rqs)
> shost->hostt->commit_rqs(shost, hctx->queue_num);
>
> then scsi_mq_ops_no_commit can be saved.
>
> Because .commit_rqs() is only called when BLK_STS_*_RESOURCE is
> returned from scsi_queue_rq(), at that time shost->hostt->commit_rqs should
> have been hit from cache given .queuecommand is called via
> host->hostt->queuecommand.

This is not about d-cache, it's about preserving the heuristics that
blk-mq applies depending on whether commit_rqs is there or not.

Paolo