RE: [RFC PATCH v6 5/5] mmc: queue: Use bigger segments if IOMMU can merge the segments

[Yoshihiro Shimoda]

Hi Wolfram-san,

> From: Wolfram Sang, Sent: Friday, June 14, 2019 4:59 AM
> 
> > -   blk_queue_max_segments(mq->queue, host->max_segs);
> > +   /* blk_queue_can_use_iommu_merging() should succeed if can_merge = 1 */
> > +   if (host->can_merge &&
> > +       !blk_queue_can_use_iommu_merging(mq->queue, mmc_dev(host)))
> > +           WARN_ON(1);
> > +   blk_queue_max_segments(mq->queue, mmc_get_max_segments(host));
> 
> Maybe we could use WARN here to save the comment and move the info to
> the printout?
> 
> -     blk_queue_max_segments(mq->queue, host->max_segs);
> +     if (host->can_merge)
> +             WARN(!blk_queue_can_use_iommu_merging(mq->queue, mmc_dev(host)),
> +                  "merging was advertised but not possible\n");
> +     blk_queue_max_segments(mq->queue, mmc_get_max_segments(host));

Thank you for the suggestion. It's a good idea! I'll fix the patch.

Best regards,
Yoshihiro Shimoda