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[142.162.113.180]) by smtp.gmail.com with ESMTPSA id q17sm2194836qtq.58.2019.11.07.12.36.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 07 Nov 2019 12:36:30 -0800 (PST) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1iSoW5-0000Io-Qj; Thu, 07 Nov 2019 16:36:29 -0400 Date: Thu, 7 Nov 2019 16:36:29 -0400 From: Jason Gunthorpe To: Boris Ostrovsky 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 , Christian =?utf-8?B?S8O2bmln?= , 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 Subject: Re: [PATCH v2 09/15] xen/gntdev: use mmu_range_notifier_insert Message-ID: <20191107203629.GF6730@ziepe.ca> References: <20191028201032.6352-1-jgg@ziepe.ca> <20191028201032.6352-10-jgg@ziepe.ca> <3938b588-c6c5-3bd1-8ea9-47e4d5b2045c@oracle.com> <20191105023108.GN22766@mellanox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org 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) { >         WARN_ON(map->vma != vma); >         ... > > > Yes, that sounds good. I amended my copy of the patch with the above, has this rework shown signs of working? @@ -436,7 +436,8 @@ static void gntdev_vma_close(struct vm_area_struct *vma) struct gntdev_priv *priv = file->private_data; pr_debug("gntdev_vma_close %p\n", vma); - if (use_ptemod && map->vma == vma) { + if (use_ptemod) { + WARN_ON(map->vma != vma); mmu_range_notifier_remove(&map->notifier); map->vma = NULL; } Jason