Re: [PATCH 1/8] scsi: add a host / host template field for the virt boundary

[Ming Lei]

On Mon, Jun 17, 2019 at 8:21 PM Christoph Hellwig <hch@xxxxxx> wrote:
>
> This allows drivers setting it up easily instead of branching out to
> block layer calls in slave_alloc, and ensures the upgraded
> max_segment_size setting gets picked up by the DMA layer.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  drivers/scsi/hosts.c     | 3 +++
>  drivers/scsi/scsi_lib.c  | 3 ++-
>  include/scsi/scsi_host.h | 3 +++
>  3 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index ff0d8c6a8d0c..55522b7162d3 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -462,6 +462,9 @@ struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
>         else
>                 shost->dma_boundary = 0xffffffff;
>
> +       if (sht->virt_boundary_mask)
> +               shost->virt_boundary_mask = sht->virt_boundary_mask;
> +
>         device_initialize(&shost->shost_gendev);
>         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
>         shost->shost_gendev.bus = &scsi_bus_type;
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 65d0a10c76ad..d333bb6b1c59 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1775,7 +1775,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
>         dma_set_seg_boundary(dev, shost->dma_boundary);
>
>         blk_queue_max_segment_size(q, shost->max_segment_size);
> -       dma_set_max_seg_size(dev, shost->max_segment_size);
> +       blk_queue_virt_boundary(q, shost->virt_boundary_mask);
> +       dma_set_max_seg_size(dev, queue_max_segment_size(q));

The patch looks fine, also suggest to make sure that max_segment_size
is block-size aligned, and un-aligned max segment size has caused trouble
on mmc.

Thanks,
Ming Lei