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b=NTVyHgZ4ej/NoJRr2JYj7UKyQlfR6XGQRr9FmbaNFpYfeUFtD11fXLEeAHp2m4iJL TNBAN5sK8DRrQUrWgPkGrR7fMZ604apkzfT0Ic36gzChdKeAZmYnGvkEl8XWKptUmb cLNb9TKDfRrzmWFzzONZlNZr6dNP6NYg1CTXXFug9/xBgWGnhtkEiSLfQ+groFJnlH IRXJu2sO9iXH53SOKFBbAfQm1E6weEIh2HjM5VaJai843ASOTzrBAJDXWvm4Uzu+Xr v5J5aK66FsIFRyYUnNEIC8pzYfvUFR8Dga4EbAxrFRpgLvgeBvpo3V834wCS/2Gb/X XeQoV828mjx1w== Date: Tue, 19 Nov 2024 15:57:43 +0200 From: Leon Romanovsky To: Will Deacon Cc: Jens Axboe , Jason Gunthorpe , Robin Murphy , Joerg Roedel , Christoph Hellwig , Sagi Grimberg , Keith Busch , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , Marek Szyprowski , =?iso-8859-1?B?Suly9G1l?= Glisse , Andrew Morton , Jonathan Corbet , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Randy Dunlap Subject: Re: [PATCH v3 07/17] dma-mapping: Implement link/unlink ranges API Message-ID: <20241119135743.GB26101@unreal> References: <20241118145929.GB27795@willie-the-truck> <20241118185533.GA24154@unreal> <20241119090507.GB28466@willie-the-truck> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241119090507.GB28466@willie-the-truck> X-Rspam-User: X-Rspamd-Queue-Id: 4A8A88001D X-Rspamd-Server: rspam01 X-Stat-Signature: syjpogwgy6d45eqznhqkd9zjrz5gcqsi X-HE-Tag: 1732024575-466329 X-HE-Meta: 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 wHn67DcU zPU2b1KpivfN6zw8RThmsGqtIBFuZ31htNA41iEk+VbxEuqAZ/ekVADSwaDACBbInaqRyAEwpWfWvxmK3RQL/JAr0Lbjt9UymC79A/Gj0IlWRxq9Nodrjztxgn1cEaYhDdSR1hx0eVEiyCxjdE9crzBPBw1ZrFCLGd9Ntzbygz6beie+4agQE65W/hVYHW2gQNo+Hcks/vol+HALneK7o1PcFmKK/XqQI8JgVVFLZbGGPYavyWTKlumlDLQ8Nu0Twt46s 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: List-Subscribe: List-Unsubscribe: On Tue, Nov 19, 2024 at 09:05:08AM +0000, Will Deacon wrote: > On Mon, Nov 18, 2024 at 08:55:33PM +0200, Leon Romanovsky wrote: > > On Mon, Nov 18, 2024 at 02:59:30PM +0000, Will Deacon wrote: > > > On Sun, Nov 10, 2024 at 03:46:54PM +0200, Leon Romanovsky wrote: > > > > +static void __iommu_dma_iova_unlink(struct device *dev, > > > > + struct dma_iova_state *state, size_t offset, size_t size, > > > > + enum dma_data_direction dir, unsigned long attrs, > > > > + bool free_iova) > > > > +{ > > > > + struct iommu_domain *domain = iommu_get_dma_domain(dev); > > > > + struct iommu_dma_cookie *cookie = domain->iova_cookie; > > > > + struct iova_domain *iovad = &cookie->iovad; > > > > + dma_addr_t addr = state->addr + offset; > > > > + size_t iova_start_pad = iova_offset(iovad, addr); > > > > + struct iommu_iotlb_gather iotlb_gather; > > > > + size_t unmapped; > > > > + > > > > + if ((state->__size & DMA_IOVA_USE_SWIOTLB) || > > > > + (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))) > > > > + iommu_dma_iova_unlink_range_slow(dev, addr, size, dir, attrs); > > > > + > > > > + iommu_iotlb_gather_init(&iotlb_gather); > > > > + iotlb_gather.queued = free_iova && READ_ONCE(cookie->fq_domain); > > > > + > > > > + size = iova_align(iovad, size + iova_start_pad); > > > > + addr -= iova_start_pad; > > > > + unmapped = iommu_unmap_fast(domain, addr, size, &iotlb_gather); > > > > + WARN_ON(unmapped != size); > > > > > > Does the new API require that the 'size' passed to dma_iova_unlink() > > > exactly match the 'size' passed to the corresponding call to > > > dma_iova_link()? I ask because the IOMMU page-table code is built around > > > the assumption that partial unmap() operations never occur (i.e. > > > operations which could require splitting a huge mapping). We just > > > removed [1] that code from the Arm IO page-table implementations, so it > > > would be good to avoid adding it back for this. > > > > dma_iova_link/dma_iova_unlink() don't have any assumptions in addition > > to already existing for dma_map_sg/dma_unmap_sg(). In reality, it means > > that all calls to unlink will have same size as for link. > > Ok, great. Any chance you could call that out in the documentation patch, > please? Can you suggest what should I add there, as it is not specific to new API, but general note applicable to all __iommu_unmap() callers? Thanks