From: Dan Williams <dan.j.williams@intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
linux-mips <linux-mips@linux-mips.org>,
"linux-ia64@vger.kernel.org" <linux-ia64@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
"David Howells" <dhowells@redhat.com>,
sparclinux@vger.kernel.org,
"Hans-Christian Egtvedt" <egtvedt@samfundet.no>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
"the arch/x86 maintainers" <x86@kernel.org>,
"David Woodhouse" <dwmw2@infradead.org>,
"Håvard Skinnemoen" <hskinnemoen@gmail.com>,
linux-xtensa@linux-xtensa.org, grundler@parisc-linux.org,
"Miao Steven" <realmz6@gmail.com>,
"Alex Williamson" <alex.williamson@redhat.com>,
linux-metag@vger.kernel.org, "Jens Axboe" <axboe@kernel.dk>,
"Michal Simek" <monstr@monstr.eu>,
"Parisc List" <linux-parisc@vger.kernel.org>,
"Vineet Gupta" <vgupta@synopsys.com>,
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linux-alpha@vger.kernel.org,
"Linux Media Mailing List" <linux-media@vger.kernel.org>,
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Subject: Re: [PATCH 29/31] parisc: handle page-less SG entries
Date: Thu, 13 Aug 2015 20:30:49 -0700 [thread overview]
Message-ID: <CAA9_cmcNA__N_yVTKsEqLAKBuoL-hx73t6opdsmb7w-0qKXaWg@mail.gmail.com> (raw)
In-Reply-To: <20150813143150.GA17183@lst.de>
On Thu, Aug 13, 2015 at 7:31 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Wed, Aug 12, 2015 at 09:01:02AM -0700, Linus Torvalds wrote:
>> I'm assuming that anybody who wants to use the page-less
>> scatter-gather lists always does so on memory that isn't actually
>> virtually mapped at all, or only does so on sane architectures that
>> are cache coherent at a physical level, but I'd like that assumption
>> *documented* somewhere.
>
> It's temporarily mapped by kmap-like helpers. That code isn't in
> this series. The most recent version of it is here:
>
> https://git.kernel.org/cgit/linux/kernel/git/djbw/nvdimm.git/commit/?h=pfn&id=de8237c99fdb4352be2193f3a7610e902b9bb2f0
>
> note that it's not doing the cache flushing it would have to do yet, but
> it's also only enabled for x86 at the moment.
For virtually tagged caches I assume we would temporarily map with
kmap_atomic_pfn_t(), similar to how drm_clflush_pages() implements
powerpc support. However with DAX we could end up with multiple
virtual aliases for a page-less pfn.
next prev parent reply other threads:[~2015-08-14 3:30 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-12 7:05 RFC: prepare for struct scatterlist entries without page backing Christoph Hellwig
2015-08-12 7:05 ` [PATCH 01/31] scatterlist: add sg_pfn and sg_has_page helpers Christoph Hellwig
2015-08-12 7:05 ` [PATCH 02/31] scatterlist: use sg_phys() Christoph Hellwig
2015-08-12 7:05 ` [PATCH 03/31] dma-debug: handle page-less SG entries Christoph Hellwig
2015-08-12 7:05 ` [PATCH 04/31] x86/pci-nommu: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 05/31] x86/pci-calgary: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 06/31] alpha/pci-noop: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 07/31] alpha/pci_iommu: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 08/31] c6x: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 09/31] ia64/pci_dma: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 10/31] powerpc/iommu: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 11/31] sparc/iommu: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 12/31] mn10300: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 13/31] sparc/ldc: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 14/31] sparc32/io-unit: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 15/31] sparc32/iommu: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 16/31] s390: " Christoph Hellwig
2015-08-12 11:51 ` Sebastian Ott
2015-08-12 7:05 ` [PATCH 17/31] ia64/sba_iommu: remove sba_sg_address Christoph Hellwig
2015-08-12 7:05 ` [PATCH 18/31] nios2: handle page-less SG entries Christoph Hellwig
2015-08-12 7:05 ` [PATCH 19/31] arc: " Christoph Hellwig
2015-08-12 10:28 ` Vineet Gupta
2015-08-12 7:05 ` [PATCH 20/31] avr32: " Christoph Hellwig
2015-08-12 9:36 ` Hans-Christian Egtvedt
2015-08-12 7:05 ` [PATCH 21/31] blackfin: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 22/31] metag: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 23/31] sh: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 24/31] xtensa: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 25/31] frv: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 26/31] openrisc: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 27/31] mips: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 28/31] powerpc: " Christoph Hellwig
2015-08-12 7:05 ` [PATCH 29/31] parisc: " Christoph Hellwig
2015-08-12 16:01 ` Linus Torvalds
2015-08-13 14:31 ` Christoph Hellwig
2015-08-14 3:30 ` Dan Williams [this message]
2015-08-14 3:59 ` James Bottomley
2015-08-14 4:11 ` David Miller
2015-08-14 16:17 ` Dan Williams
2015-08-12 7:05 ` [PATCH 30/31] intel-iommu: " Christoph Hellwig
2015-08-12 9:51 ` David Woodhouse
2015-08-12 7:05 ` [PATCH 31/31] dma-mapping-common: skip kmemleak checks for " Christoph Hellwig
2015-08-12 16:05 ` Linus Torvalds
2015-08-13 14:33 ` Christoph Hellwig
2015-08-12 16:26 ` Catalin Marinas
2015-08-12 12:42 ` RFC: prepare for struct scatterlist entries without page backing Boaz Harrosh
2015-08-12 23:37 ` Julian Calaby
2015-08-13 14:35 ` Christoph Hellwig
2015-08-13 23:40 ` Julian Calaby
2015-08-13 14:40 ` Christoph Hellwig
2015-08-13 15:42 ` Boaz Harrosh
2015-08-12 17:00 ` James Bottomley
2015-08-12 17:56 ` Grant Grundler
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