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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 48F48C4332B for ; Mon, 15 Mar 2021 16:34:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A72F64F33 for ; Mon, 15 Mar 2021 16:34:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233773AbhCOQdl (ORCPT ); Mon, 15 Mar 2021 12:33:41 -0400 Received: from ale.deltatee.com ([204.191.154.188]:41178 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233564AbhCOQdc (ORCPT ); Mon, 15 Mar 2021 12:33:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=deltatee.com; s=20200525; h=Subject:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:content-disposition; bh=25tvzr6LDKuaRWZ7Kq1InXgjrQLBkOCY64hHowQXZig=; b=jd/7txTKwBaK4XM4L4pEdPfaXK j77z2FSuQPygPyzOaNtQeB/WuPI0mEHeLQ5XoVaOvM0peJGMT0rSFK7QLdYPovQdiR6d9crYwP30V U3qzhU7lI4cnhPY5eLbFwsQgHc3dgrwJ+5RCrXGFRhWPpVYBx20B8JOfELVsToLgjg+JhMv9AAQoV QXi+qBm+8NQLJ8YR2We0YcMp4QAshPbXnXH9nMM7W7FgIHCSgDMML5rQNraVpwyWQFm6LURTNIcjG M4ZrRp9VjFELAy3KrIPg5y1v+lSFYwe8hnogW0iDZtEp5btt8nr/QzFZs11lfwZQdVaCWefOipyWS LCYU1tFQ==; Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.92) (envelope-from ) id 1lLq9a-0000OV-Kj; Mon, 15 Mar 2021 10:33:15 -0600 To: Ira Weiny Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , =?UTF-8?Q?Christian_K=c3=b6nig?= , Ira Weiny , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin References: <20210311233142.7900-1-logang@deltatee.com> <20210311233142.7900-8-logang@deltatee.com> <20210313023657.GC3402637@iweiny-DESK2.sc.intel.com> From: Logan Gunthorpe Message-ID: Date: Mon, 15 Mar 2021 10:33:13 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210313023657.GC3402637@iweiny-DESK2.sc.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: jianxin.xiong@intel.com, dave.hansen@linux.intel.com, jason@jlekstrand.net, dave.b.minturn@intel.com, andrzej.jakowski@intel.com, daniel.vetter@ffwll.ch, willy@infradead.org, ddutile@redhat.com, jhubbard@nvidia.com, iweiny@intel.com, christian.koenig@amd.com, jgg@ziepe.ca, dan.j.williams@intel.com, hch@lst.de, sbates@raithlin.com, iommu@lists.linux-foundation.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, ira.weiny@intel.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [RFC PATCH v2 07/11] dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-03-12 7:36 p.m., Ira Weiny wrote: > On Thu, Mar 11, 2021 at 04:31:37PM -0700, Logan Gunthorpe wrote: > >> +int dma_pci_p2pdma_supported(struct device *dev) > ^^^ > bool? Sure. > >> +{ >> + const struct dma_map_ops *ops = get_dma_ops(dev); >> + >> + return !ops || ops->flags & DMA_F_PCI_P2PDMA_SUPPORTED; > > Is this logic correct? I would have expected. > > return (ops && ops->flags & DMA_F_PCI_P2PDMA_SUPPORTED); If ops is NULL then the operations in kernel/dma/direct.c are used and support is added to those in patch 6. So it is correct as written. Logan