Re: [PATCH] vhost/scsi: truncate T10 PI iov_iter to prot_bytes

[Greg Edwards <gedwards@ddn.com>]

On Wed, Aug 22, 2018 at 01:21:53PM -0600, Greg Edwards wrote:
> Commands with protection information included were not truncating the
> protection iov_iter to the number of protection bytes in the command.
> This resulted in vhost_scsi mis-calculating the size of the protection
> SGL in vhost_scsi_calc_sgls(), and including both the protection and
> data SG entries in the protection SGL.
>
> Fixes: 09b13fa8c1a1 ("vhost/scsi: Add ANY_LAYOUT support in vhost_scsi_handle_vq")
> Signed-off-by: Greg Edwards <gedwards@ddn.com>


Any thoughts on this patch?


> ---
>  drivers/vhost/scsi.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index 76f8d649147b..cbe0ea26c1ff 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -964,7 +964,8 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
>  				prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin);
>  			}
>  			/*
> -			 * Set prot_iter to data_iter, and advance past any
> +			 * Set prot_iter to data_iter and truncate it to
> +			 * prot_bytes, and advance data_iter past any
>  			 * preceeding prot_bytes that may be present.
>  			 *
>  			 * Also fix up the exp_data_len to reflect only the
> @@ -973,6 +974,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
>  			if (prot_bytes) {
>  				exp_data_len -= prot_bytes;
>  				prot_iter = data_iter;
> +				iov_iter_truncate(&prot_iter, prot_bytes);
>  				iov_iter_advance(&data_iter, prot_bytes);
>  			}
>  			tag = vhost64_to_cpu(vq, v_req_pi.tag);
> --
> 2.17.1