From:   "Michael Kelley (LINUX)" <mikelley@microsoft.com>
To:     YueHaibing <yuehaibing@huawei.com>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "wei.liu@kernel.org" <wei.liu@kernel.org>,
        Dexuan Cui <decui@microsoft.com>,
        "jejb@linux.ibm.com" <jejb@linux.ibm.com>,
        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        Tianyu Lan <Tianyu.Lan@microsoft.com>,
        Long Li <longli@microsoft.com>
CC:     "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 -next] scsi: storvsc: Fix unsigned comparison to zero
Thread-Topic: [PATCH v2 -next] scsi: storvsc: Fix unsigned comparison to zero
Thread-Index: AQHX+ta2hkoFcgCpmEKSnk86KQZhY6xINKZQ
Date:   Tue, 28 Dec 2021 18:04:11 +0000
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References: <20211227040311.54584-1-yuehaibing@huawei.com>
In-Reply-To: <20211227040311.54584-1-yuehaibing@huawei.com>
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From: YueHaibing <yuehaibing@huawei.com> Sent: Sunday, December 26, 2021 8:=
03 PM
>=20
> The unsigned variable sg_count is being assigned a return value
> from the call to scsi_dma_map() that can return -ENOMEM.
>=20
> Fixes: 743b237c3a7b ("scsi: storvsc: Add Isolation VM support for storvsc=
 driver")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> ---
> v2: define sg_count as int type
> ---
>  drivers/scsi/storvsc_drv.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>=20
> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
> index ae293600d799..2273b843d9d2 100644
> --- a/drivers/scsi/storvsc_drv.c
> +++ b/drivers/scsi/storvsc_drv.c
> @@ -1753,7 +1753,6 @@ static int storvsc_queuecommand(struct Scsi_Host *h=
ost, struct scsi_cmnd *scmnd)
>  	struct hv_device *dev =3D host_dev->dev;
>  	struct storvsc_cmd_request *cmd_request =3D scsi_cmd_priv(scmnd);
>  	struct scatterlist *sgl;
> -	unsigned int sg_count;
>  	struct vmscsi_request *vm_srb;
>  	struct vmbus_packet_mpb_array  *payload;
>  	u32 payload_sz;
> @@ -1826,18 +1825,17 @@ static int storvsc_queuecommand(struct Scsi_Host =
*host, struct scsi_cmnd *scmnd)
>  	memcpy(vm_srb->cdb, scmnd->cmnd, vm_srb->cdb_length);
>=20
>  	sgl =3D (struct scatterlist *)scsi_sglist(scmnd);
> -	sg_count =3D scsi_sg_count(scmnd);
>=20
>  	length =3D scsi_bufflen(scmnd);
>  	payload =3D (struct vmbus_packet_mpb_array *)&cmd_request->mpb;
>  	payload_sz =3D sizeof(cmd_request->mpb);
>=20
> -	if (sg_count) {
> +	if (scsi_sg_count(scmnd)) {
>  		unsigned long offset_in_hvpg =3D offset_in_hvpage(sgl->offset);
>  		unsigned int hvpg_count =3D HVPFN_UP(offset_in_hvpg + length);
>  		struct scatterlist *sg;
>  		unsigned long hvpfn, hvpfns_to_add;
> -		int j, i =3D 0;
> +		int j, i =3D 0, sg_count;
>=20
>  		if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
>=20
> --
> 2.17.1

Reviewed-by: Michael Kelley <mikelley@microsoft.com>