From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 41fDhM1pf5zF0gv for ; Mon, 30 Jul 2018 19:25:55 +1000 (AEST) Date: Mon, 30 Jul 2018 02:25:51 -0700 From: Christoph Hellwig To: Anshuman Khandual Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, aik@ozlabs.ru, robh@kernel.org, joe@perches.com, elfring@users.sourceforge.net, david@gibson.dropbear.id.au, jasowang@redhat.com, benh@kernel.crashing.org, mpe@ellerman.id.au, mst@redhat.com, hch@infradead.org, linuxram@us.ibm.com, haren@linux.vnet.ibm.com, paulus@samba.org, srikar@linux.vnet.ibm.com Subject: Re: [RFC 2/4] virtio: Override device's DMA OPS with virtio_direct_dma_ops selectively Message-ID: <20180730092551.GB26245@infradead.org> References: <20180720035941.6844-1-khandual@linux.vnet.ibm.com> <20180720035941.6844-3-khandual@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20180720035941.6844-3-khandual@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > +const struct dma_map_ops virtio_direct_dma_ops; This belongs into a header if it is non-static. If you only use it in this file anyway please mark it static and avoid a forward declaration. > + > int virtio_finalize_features(struct virtio_device *dev) > { > int ret = dev->config->finalize_features(dev); > @@ -174,6 +176,9 @@ int virtio_finalize_features(struct virtio_device *dev) > if (ret) > return ret; > > + if (virtio_has_iommu_quirk(dev)) > + set_dma_ops(dev->dev.parent, &virtio_direct_dma_ops); This needs a big fat comment explaining what is going on here. Also not new, but I find the existance of virtio_has_iommu_quirk and its name horribly confusing. It might be better to open code it here once only a single caller is left.