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Thu, 07 Nov 2019 22:55:01 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xA7MsD57138401; Thu, 7 Nov 2019 22:55:01 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 2w41wb0f8s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 07 Nov 2019 22:55:01 +0000 Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xA7Msu67017548; Thu, 7 Nov 2019 22:54:56 GMT Received: from bostrovs-us.us.oracle.com (/10.152.32.65) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 07 Nov 2019 14:54:56 -0800 Subject: Re: [PATCH v2 09/15] xen/gntdev: use mmu_range_notifier_insert To: Jason Gunthorpe Cc: "linux-mm@kvack.org" , Jerome Glisse , Ralph Campbell , John Hubbard , "Felix.Kuehling@amd.com" , "linux-rdma@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "amd-gfx@lists.freedesktop.org" , Alex Deucher , Ben Skeggs , =?UTF-8?Q?Christian_K=c3=b6nig?= , David Zhou , Dennis Dalessandro , Juergen Gross , Mike Marciniszyn , Oleksandr Andrushchenko , Petr Cvek , Stefano Stabellini , "nouveau@lists.freedesktop.org" , "xen-devel@lists.xenproject.org" , Christoph Hellwig References: <20191028201032.6352-1-jgg@ziepe.ca> <20191028201032.6352-10-jgg@ziepe.ca> <3938b588-c6c5-3bd1-8ea9-47e4d5b2045c@oracle.com> <20191105023108.GN22766@mellanox.com> <20191107203629.GF6730@ziepe.ca> From: Boris Ostrovsky Autocrypt: addr=boris.ostrovsky@oracle.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191107203629.GF6730@ziepe.ca> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9434 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1910280000 definitions=main-1911070210 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9434 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1910280000 definitions=main-1911070210 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 11/7/19 3:36 PM, Jason Gunthorpe wrote: > On Tue, Nov 05, 2019 at 10:16:46AM -0500, Boris Ostrovsky wrote: > >>> So, I suppose it can be relaxed to a null test and a WARN_ON that it >>> hasn't changed? >> You mean >> >> if (use_ptemod) { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 WARN_ON(map->vma !=3D vma); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ... >> >> >> Yes, that sounds good. > I amended my copy of the patch with the above, has this rework shown > signs of working? Yes, it works fine. But please don't forget notifier ops initialization. With those two changes, Reviewed-by: Boris Ostrovsky > > @@ -436,7 +436,8 @@ static void gntdev_vma_close(struct vm_area_struct = *vma) > struct gntdev_priv *priv =3D file->private_data; > =20 > pr_debug("gntdev_vma_close %p\n", vma); > - if (use_ptemod && map->vma =3D=3D vma) { > + if (use_ptemod) { > + WARN_ON(map->vma !=3D vma); > mmu_range_notifier_remove(&map->notifier); > map->vma =3D NULL; > } > > Jason