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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 1B19713F6DFF for ; Mon, 30 Jul 2018 09:24:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7CEE20881 for ; Mon, 30 Jul 2018 09:24:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="l7niwxdH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7CEE20881 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727478AbeG3K61 (ORCPT ); Mon, 30 Jul 2018 06:58:27 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:55760 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726790AbeG3K61 (ORCPT ); Mon, 30 Jul 2018 06:58:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=mR4mX2xzq92WZ4zZaEHCdJdgLzTAz+X3zYct5j15oCI=; b=l7niwxdHp9YAzvfZREWAXLfCA c+tDzvif0yE6SKGGfv0BtIh+yqXNeA3bwjccjfidrIDBNf/e8dFJ4E2V7U3/Z4k7YL65PBoG8M/NX v1XOTnMV93wDmOjAfZ2qDHJ0/UZTN3PK/pf5bP0fP8nrA+HMqz+O6GXPO+hhqYWQ0B6DqUGJTnO1l Y+1eSYvvYiYnJF0qvQ7IxxWgKCiwtzpSKLxo8Sk3dIMO2qTI1R5zhFwG+xue8m1RKa9DLOHIiheXA d4UCKEc0Oe9icVE0t1Xue3Q3WirH8rPr7nwJtT68zlf3Q9SuJge2Gz+BuyAnjiKNgtbey08u71uZ/ zSzpvQ7Mg==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1fk4Pb-00075r-Up; Mon, 30 Jul 2018 09:24:19 +0000 Date: Mon, 30 Jul 2018 02:24:19 -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 1/4] virtio: Define virtio_direct_dma_ops structure Message-ID: <20180730092419.GA26245@infradead.org> References: <20180720035941.6844-1-khandual@linux.vnet.ibm.com> <20180720035941.6844-2-khandual@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180720035941.6844-2-khandual@linux.vnet.ibm.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > +/* > + * Virtio direct mapping DMA API operations structure > + * > + * This defines DMA API structure for all virtio devices which would not > + * either bring in their own DMA OPS from architecture or they would not > + * like to use architecture specific IOMMU based DMA OPS because QEMU > + * expects GPA instead of an IOVA in absence of VIRTIO_F_IOMMU_PLATFORM. > + */ > +dma_addr_t virtio_direct_map_page(struct device *dev, struct page *page, > + unsigned long offset, size_t size, > + enum dma_data_direction dir, > + unsigned long attrs) All these functions should probably be marked static. > +void virtio_direct_unmap_page(struct device *hwdev, dma_addr_t dev_addr, > + size_t size, enum dma_data_direction dir, > + unsigned long attrs) > +{ > +} No need to implement no-op callbacks in struct dma_map_ops. > + > +int virtio_direct_mapping_error(struct device *hwdev, dma_addr_t dma_addr) > +{ > + return 0; > +} Including this one. > +void *virtio_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, > + gfp_t gfp, unsigned long attrs) > +{ > + void *queue = alloc_pages_exact(PAGE_ALIGN(size), gfp); > + > + if (queue) { > + phys_addr_t phys_addr = virt_to_phys(queue); > + *dma_handle = (dma_addr_t)phys_addr; > + > + if (WARN_ON_ONCE(*dma_handle != phys_addr)) { > + free_pages_exact(queue, PAGE_ALIGN(size)); > + return NULL; > + } > + } > + return queue; queue is a very odd name in a generic memory allocator. > +void virtio_direct_free(struct device *dev, size_t size, void *vaddr, > + dma_addr_t dma_addr, unsigned long attrs) > +{ > + free_pages_exact(vaddr, PAGE_ALIGN(size)); > +} > + > +const struct dma_map_ops virtio_direct_dma_ops = { > + .alloc = virtio_direct_alloc, > + .free = virtio_direct_free, > + .map_page = virtio_direct_map_page, > + .unmap_page = virtio_direct_unmap_page, > + .mapping_error = virtio_direct_mapping_error, > +}; This is missing a dma_map_sg implementation. In general this is mandatory for dma_ops. So either you implement it or explain in a common why you think you can skip it. > +EXPORT_SYMBOL(virtio_direct_dma_ops); EXPORT_SYMBOL_GPL like all virtio symbols, please.