Linux Virtualization - Aug 2018 - [PATCH] vhost/scsi: increase VHOST_SCSI_PREALLOC_PROT_SGLS to 2048

On Wed, Aug 08, 2018 at 01:29:55PM -0600, Greg Edwards
wrote:
> The current value of VHOST_SCSI_PREALLOC_PROT_SGLS is too small to
> accommodate larger I/Os, e.g. 16-32 MiB, when the VIRTIO_SCSI_F_T10_PI
> feature bit is negotiated and the backing store supports T10 PI.
> 
> vhost-scsi rejects the command with errors like:
> 
> [   59.581317] vhost_scsi_calc_sgls: requested sgl_count: 1820 exceeds
pre-allocated max_sgls: 512
> 
> Signed-off-by: Greg Edwards <gedwards at ddn.com>
> ---
>  drivers/vhost/scsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index 17fcd3b2e686..8c32cf58d6fa 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -56,7 +56,7 @@
>  #define VHOST_SCSI_DEFAULT_TAGS 256
>  #define VHOST_SCSI_PREALLOC_SGLS 2048
>  #define VHOST_SCSI_PREALLOC_UPAGES 2048
> -#define VHOST_SCSI_PREALLOC_PROT_SGLS 512
> +#define VHOST_SCSI_PREALLOC_PROT_SGLS 2048
>  
>  struct vhost_scsi_inflight {
>  	/* Wait for the flush operation to finish */
I guess it's ok since PREALLOC_SGLS is already 2K ... or
am I missing something. Paolo, any input on this?

> -- 
> 2.17.1