Re: [PATCH] scsi: core: Set BLK_FEAT_SKIP_TAGSET_QUIESCE on pseudo SCSI devices

[Bart Van Assche <bvanassche@acm.org>]

On 9/1/26 5:23 AM, Stanley Jhu wrote:
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 3b82e80e807a..eb48866ed0dc 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -336,6 +336,8 @@ static struct scsi_device *scsi_alloc_sdev(struct
> scsi_target *starget,
>          sdev->sg_reserved_size = INT_MAX;
> 
>          scsi_init_limits(shost, &lim);
> +       if (scsi_device_is_pseudo_dev(sdev))
> +               lim.features |= BLK_FEAT_SKIP_TAGSET_QUIESCE;
>          q = blk_mq_alloc_queue(&sdev->host->tag_set, &lim, sdev);
>          if (IS_ERR(q)) {
>                  /* release fn is set up in scsi_sysfs_device_initialise, so

The above change will break frequency scaling because
ufshcd_pause_command_processing() also calls blk_mq_quiesce_tagset(),
isn't it? Has it been considered to remove the blk_mq_unquiesce_tagset()
call from ufshcd_err_handling_unprepare() and to change the
blk_mq_quiesce_tagset() call in ufshcd_err_handling_prepare() into
blk_mq_wait_quiesce_done()? The following comment can be kept:
	/* Wait for ongoing ufshcd_queuecommand() calls to finish. */

Thanks,

Bart.