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h=Subject:In-Reply-To:MIME-Version:Date: Message-ID:From:References:Cc:To:content-disposition; bh=f3Yr8sCXxE6UDrZoKKM6KXdKnffWXsnxW1/wIjh8k4A=; b=KEBNlEo7fZE8oPSxjxUqE7MmyT 127yU5GY+VbA0DuEsKtpgx7QIgzkFQHqXPgY9U0COrkNxD66a5bIJIo1pfD0XYxRz6DvC2BQHPrPj eL4xUpcfQzpRIIJ/Y7WBM96E9w9oCFIfUY8grm9AeAmMeMtk4c6ieeoJb2bz1mdkFiuWyEzB8BRPm stRVyubPxgtevJySALuOfdPQk0ykwr7G5kqAO9LSV7h7O6tyiZ/S2SuuoVNffPgaXyXDMPHhoIBq1 0nrgSmo8NrgcGPW6+bz50YQknsxlCNblp2Ogz1cUQWF2cEw0Eu7bXo5Q5eYWVgbOrbBfd9eHVDK3c 6xtpL6VA==; Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.92) (envelope-from ) id 1ldbbu-0004G9-Ev; Mon, 03 May 2021 10:39:55 -0600 To: John Hubbard , 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 Cc: Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , =?UTF-8?Q?Christian_K=c3=b6nig?= , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy References: <20210408170123.8788-1-logang@deltatee.com> <20210408170123.8788-8-logang@deltatee.com> From: Logan Gunthorpe Message-ID: <31b17b7d-f6de-c205-d1a3-e570928605f4@deltatee.com> Date: Mon, 3 May 2021 10:39:53 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: 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: robin.murphy@arm.com, ira.weiny@intel.com, helgaas@kernel.org, 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, 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, jhubbard@nvidia.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH 07/16] PCI/P2PDMA: Make pci_p2pdma_map_type() non-static 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) X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 7E2165001522 X-Stat-Signature: d6wuwzk3nrcfenwjyg3iwp6prgu65mf6 Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=deltatee.com header.s=20200525 header.b=KEBNlEo7; spf=pass (imf01.hostedemail.com: domain of logang@deltatee.com designates 204.191.154.188 as permitted sender) smtp.mailfrom=logang@deltatee.com; dmarc=none Received-SPF: none (deltatee.com>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=ale.deltatee.com; client-ip=204.191.154.188 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620059994-917287 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2021-05-02 4:44 p.m., John Hubbard wrote: > On 4/8/21 10:01 AM, Logan Gunthorpe wrote: >> pci_p2pdma_map_type() will be needed by the dma-iommu map_sg >> implementation because it will need to determine the mapping type >> ahead of actually doing the mapping to create the actual iommu mapping. >> >> Signed-off-by: Logan Gunthorpe >> --- >> drivers/pci/p2pdma.c | 34 +++++++++++++++++++++++----------- >> include/linux/pci-p2pdma.h | 15 +++++++++++++++ >> 2 files changed, 38 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c >> index bcb1a6d6119d..38c93f57a941 100644 >> --- a/drivers/pci/p2pdma.c >> +++ b/drivers/pci/p2pdma.c >> @@ -20,13 +20,6 @@ >> #include >> #include >> >> -enum pci_p2pdma_map_type { >> - PCI_P2PDMA_MAP_UNKNOWN = 0, >> - PCI_P2PDMA_MAP_NOT_SUPPORTED, >> - PCI_P2PDMA_MAP_BUS_ADDR, >> - PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, >> -}; >> - >> struct pci_p2pdma { >> struct gen_pool *pool; >> bool p2pmem_published; >> @@ -822,13 +815,30 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) >> } >> EXPORT_SYMBOL_GPL(pci_p2pmem_publish); >> >> -static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, >> - struct device *dev) >> +/** >> + * pci_p2pdma_map_type - return the type of mapping that should be used for >> + * a given device and pgmap >> + * @pgmap: the pagemap of a page to determine the mapping type for >> + * @dev: device that is mapping the page >> + * @dma_attrs: the attributes passed to the dma_map operation -- >> + * this is so they can be checked to ensure P2PDMA pages were not >> + * introduced into an incorrect interface (like dma_map_sg). * >> + * >> + * Returns one of: >> + * PCI_P2PDMA_MAP_NOT_SUPPORTED - The mapping should not be done >> + * PCI_P2PDMA_MAP_BUS_ADDR - The mapping should use the PCI bus address >> + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE - The mapping should be done directly >> + */ >> +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, >> + struct device *dev, unsigned long dma_attrs) >> { >> struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider; >> enum pci_p2pdma_map_type ret; >> struct pci_dev *client; >> >> + WARN_ONCE(!(dma_attrs & __DMA_ATTR_PCI_P2PDMA), >> + "PCI P2PDMA pages were mapped with dma_map_sg!"); > > This really ought to also return -EINVAL, assuming that my review suggestions > about return types, in earlier patches, are acceptable. That can't happen because, by convention, dma_map_sg() cannot return -EINVAL. I think the best we can do is proceed normally and just warn loudly. Logan