From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BD06C7618B for ; Tue, 23 Jul 2019 15:38:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED946223BA for ; Tue, 23 Jul 2019 15:38:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388658AbfGWPix (ORCPT ); Tue, 23 Jul 2019 11:38:53 -0400 Received: from verein.lst.de ([213.95.11.211]:42780 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727598AbfGWPix (ORCPT ); Tue, 23 Jul 2019 11:38:53 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 93A4868B02; Tue, 23 Jul 2019 17:38:51 +0200 (CEST) Date: Tue, 23 Jul 2019 17:38:51 +0200 From: Christoph Hellwig To: Robin Murphy Cc: Eric Auger , eric.auger.pro@gmail.com, hch@lst.de, m.szyprowski@samsung.com, mst@redhat.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] virtio/virtio_ring: Fix the dma_max_mapping_size call Message-ID: <20190723153851.GE720@lst.de> References: <20190722145509.1284-1-eric.auger@redhat.com> <20190722145509.1284-3-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 22, 2019 at 04:36:09PM +0100, Robin Murphy wrote: >> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c >> index c8be1c4f5b55..37c143971211 100644 >> --- a/drivers/virtio/virtio_ring.c >> +++ b/drivers/virtio/virtio_ring.c >> @@ -262,7 +262,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev) >> { >> size_t max_segment_size = SIZE_MAX; >> - if (vring_use_dma_api(vdev)) >> + if (vring_use_dma_api(vdev) && vdev->dev.dma_mask) > > Hmm, might it make sense to roll that check up into vring_use_dma_api() > itself? After all, if the device has no mask then it's likely that other > DMA API ops wouldn't really work as expected either. Makes sense to me.