From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org> To: Russell King - ARM Linux <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org> Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-xtensa-PjhNF2WwrV/0Sa2dR60CXw@public.gmane.org, Michal Simek <monstr-pSz03upnqPeHXe+LvDLADg@public.gmane.org>, linux-snps-arc-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-c6x-dev-jPsnJVOj+W6hPH1hqNUYSQ@public.gmane.org, linux-parisc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-m68k-cunTk1MwBs8S/qaLPR03pWD2FQJk+8+b@public.gmane.org, linux-hexagon-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, openrisc-cunTk1MwBs9a3B2Vnqf2dGD2FQJk+8+b@public.gmane.org, Greentime Hu <green.hu-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, linux-alpha-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sparclinux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, nios2-dev-g9ZBwUv/Ih/yUk5EbOjzuce+I+R0W71w@public.gmane.org, Vincent Chen <deanbo422-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Subject: Re: [PATCH 04/20] arm-nommu: use generic dma_noncoherent_ops Date: Tue, 22 May 2018 13:53:20 +0200 [thread overview] Message-ID: <20180522115320.GA14530@lst.de> (raw) In-Reply-To: <20180511091114.GA16141-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org> On Fri, May 11, 2018 at 10:11:15AM +0100, Russell King - ARM Linux wrote: > > +void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr, > > + size_t size, enum dma_data_direction dir) > > Please no. There is a lot of history of these (__dma_page_cpu_to_dev etc) > functions being abused by out of tree drivers, because they think they > know better. This is stopped by making them static and ensuring that > drivers have no access to these functions. > > Please do not re-expose these to the global kernel. > > While it may make things easier for a cross-architecture point of view, > it makes it a lot easier for people to abuse these private APIs. The point of this series, which isn't fully archived yet, is to consolidate the direct mapping dma code, that is all dma_map_ops instances except for iommus. It is in fact in many ways modelled after the ARM code. For that we need the architectures to supply the cache maintainance routines. However, even if they now appear in dma-noncoherent.h they are NOT and will NOT be exported, so using them directly from drivers won't easily be possible. I'll drop the arm-nommu patch for now, but I will pester your with this again once arm is the last architecture not sharing the common code. > > -- > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up > According to speedtest.net: 8.21Mbps down 510kbps up ---end quoted text---
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de> To: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: Christoph Hellwig <hch@lst.de>, iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-xtensa@linux-xtensa.org, Michal Simek <monstr@monstr.eu>, Vincent Chen <deanbo422@gmail.com>, linux-c6x-dev@linux-c6x.org, linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, openrisc@lists.librecores.org, Greentime Hu <green.hu@gmail.com>, linux-alpha@vger.kernel.org, sparclinux@vger.kernel.org, nios2-dev@lists.rocketboards.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 04/20] arm-nommu: use generic dma_noncoherent_ops Date: Tue, 22 May 2018 13:53:20 +0200 [thread overview] Message-ID: <20180522115320.GA14530@lst.de> (raw) Message-ID: <20180522115320._Ttp92tMIi7j6StjwxrOqGPjY70mhvf6lmg5VekZ3fw@z> (raw) In-Reply-To: <20180511091114.GA16141@n2100.armlinux.org.uk> On Fri, May 11, 2018 at 10:11:15AM +0100, Russell King - ARM Linux wrote: > > +void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr, > > + size_t size, enum dma_data_direction dir) > > Please no. There is a lot of history of these (__dma_page_cpu_to_dev etc) > functions being abused by out of tree drivers, because they think they > know better. This is stopped by making them static and ensuring that > drivers have no access to these functions. > > Please do not re-expose these to the global kernel. > > While it may make things easier for a cross-architecture point of view, > it makes it a lot easier for people to abuse these private APIs. The point of this series, which isn't fully archived yet, is to consolidate the direct mapping dma code, that is all dma_map_ops instances except for iommus. It is in fact in many ways modelled after the ARM code. For that we need the architectures to supply the cache maintainance routines. However, even if they now appear in dma-noncoherent.h they are NOT and will NOT be exported, so using them directly from drivers won't easily be possible. I'll drop the arm-nommu patch for now, but I will pester your with this again once arm is the last architecture not sharing the common code. > > -- > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up > According to speedtest.net: 8.21Mbps down 510kbps up ---end quoted text---
next prev parent reply other threads:[~2018-05-22 11:53 UTC|newest] Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-11 7:59 common non-cache coherent direct dma mapping ops Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 01/20] dma-mapping: simplify Kconfig dependencies Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig [not found] ` <20180511075945.16548-1-hch-jcswGhMUV9g@public.gmane.org> 2018-05-11 7:59 ` [PATCH 02/20] dma-mapping: provide a generic dma-noncoherent implementation Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig [not found] ` <20180511075945.16548-3-hch-jcswGhMUV9g@public.gmane.org> 2018-05-18 13:03 ` Alexey Brodkin 2018-05-18 13:03 ` Alexey Brodkin [not found] ` <bad125dff49f6e49c895e818c9d1abb346a46e8e.camel-HKixBCOQz3hWk0Htik3J/w@public.gmane.org> 2018-05-18 13:27 ` hch-jcswGhMUV9g 2018-05-18 13:27 ` hch [not found] ` <20180518132731.GA31125-jcswGhMUV9g@public.gmane.org> 2018-05-18 14:13 ` Alexey Brodkin 2018-05-18 14:13 ` Alexey Brodkin 2018-05-18 17:28 ` Vineet Gupta 2018-05-18 17:28 ` Vineet Gupta 2018-05-18 17:20 ` dma_sync_*_for_cpu and direction=TO_DEVICE (was Re: [PATCH 02/20] dma-mapping: provide a generic dma-noncoherent implementation) Vineet Gupta 2018-05-18 17:20 ` Vineet Gupta 2018-05-18 17:50 ` Russell King - ARM Linux 2018-05-18 17:50 ` Russell King - ARM Linux [not found] ` <20180518175004.GF17671-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org> 2018-05-18 19:57 ` Alexey Brodkin 2018-05-18 19:57 ` Alexey Brodkin [not found] ` <182840dedb4890a88c672b1c5d556920bf89a8fb.camel-HKixBCOQz3hWk0Htik3J/w@public.gmane.org> 2018-05-18 21:33 ` Russell King - ARM Linux 2018-05-18 21:33 ` Russell King - ARM Linux 2018-05-18 20:35 ` Vineet Gupta 2018-05-18 20:35 ` Vineet Gupta 2018-05-18 21:55 ` Russell King - ARM Linux 2018-05-18 21:55 ` Russell King - ARM Linux 2018-05-18 20:05 ` [PATCH 02/20] dma-mapping: provide a generic dma-noncoherent implementation Helge Deller 2018-05-18 20:05 ` Helge Deller [not found] ` <0c5d27e9-2799-eb38-8b09-47a04c48b5c7-Mmb7MZpHnFY@public.gmane.org> 2018-05-19 6:38 ` hch-jcswGhMUV9g 2018-05-19 6:38 ` hch 2018-05-11 7:59 ` [PATCH 03/20] arc: use generic dma_noncoherent_ops Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig [not found] ` <20180511075945.16548-4-hch-jcswGhMUV9g@public.gmane.org> 2018-05-11 12:44 ` Alexey Brodkin 2018-05-11 12:44 ` Alexey Brodkin 2018-05-11 7:59 ` [PATCH 04/20] arm-nommu: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig [not found] ` <20180511075945.16548-5-hch-jcswGhMUV9g@public.gmane.org> 2018-05-11 9:11 ` Russell King - ARM Linux 2018-05-11 9:11 ` Russell King - ARM Linux [not found] ` <20180511091114.GA16141-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org> 2018-05-22 11:53 ` Christoph Hellwig [this message] 2018-05-22 11:53 ` Christoph Hellwig 2018-05-11 13:56 ` John Garry 2018-05-11 13:56 ` John Garry 2018-05-11 7:59 ` [PATCH 05/20] c6x: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig [not found] ` <20180511075945.16548-6-hch-jcswGhMUV9g@public.gmane.org> 2018-05-15 0:25 ` [Linux-c6x-dev] " Mark Salter 2018-05-15 0:25 ` Mark Salter 2018-05-11 7:59 ` [PATCH 06/20] hexagon: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 07/20] m68k: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 08/20] microblaze: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 09/20] microblaze: remove the consistent_sync and consistent_sync_page Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 10/20] nds32: use generic dma_noncoherent_ops Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 11/20] nios2: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 12/20] openrisc: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 13/20] sh: simplify get_arch_dma_ops Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 14/20] sh: introduce a sh_cacheop_vaddr helper Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 15/20] sh: use dma_direct_ops for the CONFIG_DMA_COHERENT case Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 16/20] mm: split arch/sh/mm/consistent.c Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 17/20] sh: use generic dma_noncoherent_ops Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 18/20] xtensa: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 19/20] sparc: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-11 7:59 ` [PATCH 20/20] parisc: " Christoph Hellwig 2018-05-11 7:59 ` Christoph Hellwig 2018-05-13 13:26 ` common non-cache coherent direct dma mapping ops Helge Deller 2018-05-13 13:26 ` Helge Deller
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