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

KY Srinivasan
2015-06-28T02:36:44Z

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> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@redhat.com]
> Sent: Thursday, June 25, 2015 9:12 AM
> To: linux-scsi@vger.kernel.org
> Cc: Long Li; KY Srinivasan; Haiyang Zhang; James E.J. Bottomley;
> devel@linuxdriverproject.org; linux-kernel@vger.kernel.org; Radim KrÄmÃ¡Å™
> 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 KrÄmÃ¡Å™ <rkrcmar@redhat.com>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> ---
> 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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