Re: [PATCH] scsi: sg: fix SG_DXFER_FROM_DEV transfers

[Hannes Reinecke]

On 07/05/2017 03:49 PM, Johannes Thumshirn wrote:
> SG_DXFER_FROM_DEV transfers do not have a dxferp as we set it to NULL,
> but must have a length bigger than 0. This fixes a regression introduced
> by commit 28676d869bbb ("scsi: sg: check for valid direction before
> starting the request")
> 
> Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> Fixes: 28676d869bbb ("scsi: sg: check for valid direction before starting the request")
> Reported-by: Chris Clayton <chris2553@xxxxxxxxxxxxxx>
> Tested-by: Chris Clayton <chris2553@xxxxxxxxxxxxxx>
> Cc: Doug Gilbert <dgilbert@xxxxxxxxxxxx>
> ---
>  drivers/scsi/sg.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
> index 21225d62b0c1..3c91593260aa 100644
> --- a/drivers/scsi/sg.c
> +++ b/drivers/scsi/sg.c
> @@ -758,8 +758,11 @@ static bool sg_is_valid_dxfer(sg_io_hdr_t *hp)
>  		if (hp->dxferp || hp->dxfer_len > 0)
>  			return false;
>  		return true;
> -	case SG_DXFER_TO_DEV:
>  	case SG_DXFER_FROM_DEV:
> +		if (hp->dxferp || hp->dxfer_len < 0)
> +			return false;
> +		return true;
> +	case SG_DXFER_TO_DEV:
>  	case SG_DXFER_TO_FROM_DEV:
>  		if (!hp->dxferp || hp->dxfer_len == 0)
>  			return false;
> 
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>

Cheers,

Hannes
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