From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH v2] scsi: Change sense buffer size to 252 Date: Fri, 14 Mar 2014 07:51:42 +0100 Message-ID: <5322A6FE.60209@suse.de> References: <1394776805-6784-1-git-send-email-famz@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1394776805-6784-1-git-send-email-famz@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Fam Zheng , linux-kernel@vger.kernel.org Cc: linux-scsi@vger.kernel.org, kvm@vger.kernel.org, pbonzini@redhat.com List-Id: linux-scsi@vger.kernel.org On 03/14/2014 07:00 AM, Fam Zheng wrote: > According to SPC-4, section 4.5.2.1, 252 is the limit of sense data. = So > increase the values. >=20 > Tested by hacking QEMU to fake virtio-scsi request sense len to 252. > Without this patch the driver stops working immediately when it gets = the > request. >=20 > Signed-off-by: Fam Zheng > --- > include/linux/virtio_scsi.h | 2 +- > include/scsi/scsi_cmnd.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) >=20 > diff --git a/include/linux/virtio_scsi.h b/include/linux/virtio_scsi.= h > index 4195b97..a437f7f 100644 > --- a/include/linux/virtio_scsi.h > +++ b/include/linux/virtio_scsi.h > @@ -28,7 +28,7 @@ > #define _LINUX_VIRTIO_SCSI_H > =20 > #define VIRTIO_SCSI_CDB_SIZE 32 > -#define VIRTIO_SCSI_SENSE_SIZE 96 > +#define VIRTIO_SCSI_SENSE_SIZE 252 > =20 > /* SCSI command request, followed by data-out */ > struct virtio_scsi_cmd_req { > diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h > index 91558a1..a64dac03 100644 > --- a/include/scsi/scsi_cmnd.h > +++ b/include/scsi/scsi_cmnd.h > @@ -104,7 +104,7 @@ struct scsi_cmnd { > struct request *request; /* The command we are > working on */ > =20 > -#define SCSI_SENSE_BUFFERSIZE 96 > +#define SCSI_SENSE_BUFFERSIZE 252 > unsigned char *sense_buffer; > /* obtained by REQUEST SENSE when > * CHECK CONDITION is received on original >=20 Not without careful review. Blindly increasing the buffersize is not a good idea; this define is used at several locations and even within the drivers themselves. So we cannot just increase the define for the SCSI stack. And, btw, so far I haven't come across any issue where a sense buffer overflow occurred. We first need to implement a proper sense code handling (descriptor sense parsing etc) before we need to worry about this. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg)