RE: [PATCH] scsi: storvsc: be more picky about scmnd->sc_data_direction

[KY Srinivasan]

> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx]
> Sent: Thursday, June 25, 2015 9:12 AM
> To: linux-scsi@xxxxxxxxxxxxxxx
> Cc: Long Li; KY Srinivasan; Haiyang Zhang; James E.J. Bottomley;
> devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Radim KrÄmÃÅ
> Subject: [PATCH] scsi: storvsc: be more picky about scmnd-
> >sc_data_direction
> 
> Under the 'default' case in scmnd->sc_data_direction we have 3 options:
> - DMA_NONE which we handle correctly.
> - DMA_BIDIRECTIONAL which is never supposed to be set by SCSI stack.
> - Garbage value.
> 
> Do WARN() and return -EINVAL in the last two cases. virtio_scsi does
> BUG_ON() here but it looks like an overkill.
> 
> Reported-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> ---
>  drivers/scsi/storvsc_drv.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index 3c6584f..61f4855 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1598,10 +1598,18 @@ static int storvsc_queuecommand(struct
> Scsi_Host *host, struct scsi_cmnd *scmnd)
>  		vm_srb->data_in = READ_TYPE;
>  		vm_srb->win8_extension.srb_flags |=
> SRB_FLAGS_DATA_IN;
>  		break;
> -	default:
> +	case DMA_NONE:
>  		vm_srb->data_in = UNKNOWN_TYPE;
>  		vm_srb->win8_extension.srb_flags |=
> SRB_FLAGS_NO_DATA_TRANSFER;
>  		break;
> +	default:
> +		/*
> +		 * This is DMA_BIDIRECTIONAL or something else we are
> never
> +		 * supposed to see here.
> +		 */
> +		WARN(1, "Unexpected data direction: %d\n",
> +		     scmnd->sc_data_direction);
> +		return -EINVAL;
>  	}
> 
> 
> --
> 2.4.3

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