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Sun, 27 Jul 2025 19:02:54 +0000 Received: from CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732]) by CH3PR12MB8659.namprd12.prod.outlook.com ([fe80::6eb6:7d37:7b4b:1732%7]) with mapi id 15.20.8964.024; Sun, 27 Jul 2025 19:02:54 +0000 Date: Sun, 27 Jul 2025 16:02:52 -0300 From: Jason Gunthorpe To: Christoph Hellwig Cc: Leon Romanovsky , Alex Williamson , Leon Romanovsky , Andrew Morton , Bjorn Helgaas , Christian =?utf-8?B?S8O2bmln?= , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: Re: [PATCH 05/10] PCI/P2PDMA: Export pci_p2pdma_map_type() function Message-ID: <20250727190252.GF7551@nvidia.com> References: <82e62eb59afcd39b68ae143573d5ed113a92344e.1753274085.git.leonro@nvidia.com> <20250724080313.GA31887@lst.de> Content-Type: text/plain; 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So what's the plan? Today the new DMA API broadly has the pattern: switch (pci_p2pdma_state(p2pdma_state, dev, page)) { [..] if (dma_use_iova(state)) { ret = dma_iova_link(dev, state, paddr, offset, [..] } else { dma_addr = dma_map_page(dev, page, 0, map->dma_entry_size, [..] You can't fully use the new API flow without calling pci_p2pdma_state(), which is also not exported today. Is the idea the full new DMA API flow should not be available to modules? We did export dma_iova_link(). Otherwise, the p2p step needs two functions - a struct page-full and a struct page-less version, and they need to be exported. The names here are not so good, it would be nicer to have them be a dma_* prefixed function since they are used with the other dma_ functions. Jason