From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Date: Thu, 22 Nov 2018 17:14:47 +0000 Subject: Re: remove the ->mapping_error method from dma_map_ops V2 Message-Id: <20181122171446.GJ30658@n2100.armlinux.org.uk> List-Id: References: <20181122140320.24080-1-hch@lst.de> <20181122170715.GI30658@n2100.armlinux.org.uk> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Linus Torvalds Cc: Christoph Hellwig , linux-arch@vger.kernel.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, David Woodhouse , joro@8bytes.org, the arch/x86 maintainers , Linux List Kernel Mailing , iommu@lists.linux-foundation.org, jdmason@kudzu.us, xen-devel@lists.xenproject.org, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com On Thu, Nov 22, 2018 at 09:09:47AM -0800, Linus Torvalds wrote: > On Thu, Nov 22, 2018 at 9:07 AM Russell King - ARM Linux > wrote: > > > > I'm afraid that won't work very well - 32 bit platforms with 64-bit > > addresses (LPAE) would have dma_addr_t as a 64-bit value, which > > wouldn't fit into an unsigned long. > > Good point. So we'd have to have a special IS_DMA_ERR() function that > takes a dma_addr_t and checks the same "is it the top 4095 values". No problem with that. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up