Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
IronPort-SDR: y8CTny0LC/V1noKToXyYmjlSRkjEWBCa8R9UyHHRDrsTg6H4pJD9E2pMDkdVBOVEFV2LhrUVDz
 C+pV3Pn3MXKw==
IronPort-SDR: EEp2Qq4JWbGjMbstSwM05aCaqBYkmtYJKSZCLXvQSF1cFKau87tiqI/8VXmeFP2pQCpZ5BbU8b
 N5MABNnXAMLA==
From:   "Ruhl, Michael J" <michael.j.ruhl@intel.com>
To:     Shane Francis <bigbeeshane@gmail.com>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
CC:     "airlied@linux.ie" <airlied@linux.ie>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "amd-gfx-request@lists.freedesktop.org" 
        <amd-gfx-request@lists.freedesktop.org>,
        "alexander.deucher@amd.com" <alexander.deucher@amd.com>,
        "christian.koenig@amd.com" <christian.koenig@amd.com>
Subject: RE: [PATCH v4 2/3] drm/amdgpu: fix scatter-gather mapping with user
 pages
Thread-Topic: [PATCH v4 2/3] drm/amdgpu: fix scatter-gather mapping with
 user pages
Thread-Index: AQHWAoURGp10wyvAFUutB03QxzFyZahZVeWw
Date:   Wed, 25 Mar 2020 14:00:24 +0000
Message-ID: <14063C7AD467DE4B82DEDB5C278E8663FFFBD444@fmsmsx107.amr.corp.intel.com>
References: <20200325090741.21957-1-bigbeeshane@gmail.com>
 <20200325090741.21957-3-bigbeeshane@gmail.com>
In-Reply-To: <20200325090741.21957-3-bigbeeshane@gmail.com>
Accept-Language: en-US
Content-Language: en-US
dlp-product: dlpe-windows
dlp-version: 11.2.0.6
dlp-reaction: no-action
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 8BIT
MIME-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

>-----Original Message-----
>From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of
>Shane Francis
>Sent: Wednesday, March 25, 2020 5:08 AM
>To: dri-devel@lists.freedesktop.org
>Cc: airlied@linux.ie; linux-kernel@vger.kernel.org; bigbeeshane@gmail.com;
>amd-gfx-request@lists.freedesktop.org; alexander.deucher@amd.com;
>christian.koenig@amd.com
>Subject: [PATCH v4 2/3] drm/amdgpu: fix scatter-gather mapping with user
>pages
>
>Calls to dma_map_sg may return segments / entries than requested

"may return less segments/entries" ?
                       ^^^
>if they fall on page bounderies. The old implementation did not
>support this use case.
>
>Signed-off-by: Shane Francis <bigbeeshane@gmail.com>
>---
> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>index dee446278417..c6e9885c071f 100644
>--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
>@@ -974,7 +974,7 @@ static int amdgpu_ttm_tt_pin_userptr(struct ttm_tt
>*ttm)
> 	/* Map SG to device */
> 	r = -ENOMEM;
> 	nents = dma_map_sg(adev->dev, ttm->sg->sgl, ttm->sg->nents,
>direction);
>-	if (nents != ttm->sg->nents)
>+	if (nents == 0)
> 		goto release_sg;

this looks correct to me.

Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>

> 	/* convert SG to linear array of pages and dma addresses */
>--
>2.26.0
>
>_______________________________________________
>dri-devel mailing list
>dri-devel@lists.freedesktop.org
>https://lists.freedesktop.org/mailman/listinfo/dri-devel