* tip/x86/dma fix for arc and s390 (at least) @ 2018-03-28 13:35 Christoph Hellwig [not found] ` <20180328133535.17302-1-hch-jcswGhMUV9g@public.gmane.org> 0 siblings, 1 reply; 4+ messages in thread From: Christoph Hellwig @ 2018-03-28 13:35 UTC (permalink / raw) To: x86-DgEjT+Ai2ygdnm+yROfE0A Cc: Evgeniy Didin, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA, Sebastian Ott, linux-kernel-u79uwXL29TY76Z2rM5mHXA Hi all, this restores previous __GFP_ZERO passthrough behavior for now as arc and s390 rely on it. Needs more work to sort out the API mess in the long run. ^ permalink raw reply [flat|nested] 4+ messages in thread
[parent not found: <20180328133535.17302-1-hch-jcswGhMUV9g@public.gmane.org>]
* [PATCH] dma-mapping: don't clear GFP_ZERO in dma_alloc_attrs [not found] ` <20180328133535.17302-1-hch-jcswGhMUV9g@public.gmane.org> @ 2018-03-28 13:35 ` Christoph Hellwig [not found] ` <20180328133535.17302-2-hch-jcswGhMUV9g@public.gmane.org> 0 siblings, 1 reply; 4+ messages in thread From: Christoph Hellwig @ 2018-03-28 13:35 UTC (permalink / raw) To: x86-DgEjT+Ai2ygdnm+yROfE0A Cc: Evgeniy Didin, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA, Sebastian Ott, linux-kernel-u79uwXL29TY76Z2rM5mHXA Revert the clearing of __GFP_ZERO in dma_alloc_attrs and move it to dma_direct_alloc for now. While most common architectures always zero dma cohereny allocations (and x86 did so since day one) this is not documented and at least arc and s390 do not zero without the explicit __GFP_ZERO argument. Fixes: 57bf5a8963f8 ("dma-mapping: clear harmful GFP_* flags in common code") Reported-by: Evgeniy Didin <Evgeniy.Didin-HKixBCOQz3hWk0Htik3J/w@public.gmane.org> Reported-by: Sebastian Ott <sebott-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org> --- include/linux/dma-mapping.h | 8 ++------ lib/dma-direct.c | 3 +++ 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index eb9eab4ecd6d..12fedcba9a9a 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -518,12 +518,8 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size, if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr)) return cpu_addr; - /* - * Let the implementation decide on the zone to allocate from, and - * decide on the way of zeroing the memory given that the memory - * returned should always be zeroed. - */ - flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM | __GFP_ZERO); + /* let the implementation decide on the zone to allocate from: */ + flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM); if (!arch_dma_alloc_attrs(&dev, &flag)) return NULL; diff --git a/lib/dma-direct.c b/lib/dma-direct.c index 1277d293d4da..c0bba30fef0a 100644 --- a/lib/dma-direct.c +++ b/lib/dma-direct.c @@ -59,6 +59,9 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, struct page *page = NULL; void *ret; + /* we always manually zero the memory once we are done: */ + gfp &= ~__GFP_ZERO; + /* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */ if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS)) gfp |= GFP_DMA; -- 2.14.2 ^ permalink raw reply related [flat|nested] 4+ messages in thread
[parent not found: <20180328133535.17302-2-hch-jcswGhMUV9g@public.gmane.org>]
* Re: [PATCH] dma-mapping: don't clear GFP_ZERO in dma_alloc_attrs [not found] ` <20180328133535.17302-2-hch-jcswGhMUV9g@public.gmane.org> @ 2018-03-28 15:12 ` Evgeniy Didin [not found] ` <1522249966.2593.14.camel-HKixBCOQz3hWk0Htik3J/w@public.gmane.org> 0 siblings, 1 reply; 4+ messages in thread From: Evgeniy Didin @ 2018-03-28 15:12 UTC (permalink / raw) To: hch-jcswGhMUV9g, x86-DgEjT+Ai2ygdnm+yROfE0A Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA, sebott-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8, linux-kernel-u79uwXL29TY76Z2rM5mHXA, Evgeniy.Didin-HKixBCOQz3hWk0Htik3J/w, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA, linux-snps-arc-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r Adding linux-snps and linux-arch mailing lists. > Revert the clearing of __GFP_ZERO in dma_alloc_attrs and move it to > dma_direct_alloc for now. While most common architectures always zero dma > cohereny allocations (and x86 did so since day one) this is not documented > and at least arc and s390 do not zero without the explicit __GFP_ZERO > argument. This patch fixed Ethernet issues on ARC HSDK. https://www.spinics.net/lists/kernel/msg2762054.html Tested-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com> > Fixes: 57bf5a8963f8 ("dma-mapping: clear harmful GFP_* flags in common code") > Reported-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com> > Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com> > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > include/linux/dma-mapping.h | 8 ++------ > lib/dma-direct.c | 3 +++ > 2 files changed, 5 insertions(+), 6 deletions(-) > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index eb9eab4ecd6d..12fedcba9a9a 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -518,12 +518,8 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size, > if (dma_alloc_from_dev_coherent(dev, size, dma_handle, &cpu_addr)) > return cpu_addr; > > - /* > - * Let the implementation decide on the zone to allocate from, and > - * decide on the way of zeroing the memory given that the memory > - * returned should always be zeroed. > - */ > - flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM | __GFP_ZERO); > + /* let the implementation decide on the zone to allocate from: */ > + flag &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM); > > if (!arch_dma_alloc_attrs(&dev, &flag)) > return NULL; > diff --git a/lib/dma-direct.c b/lib/dma-direct.c > index 1277d293d4da..c0bba30fef0a 100644 > --- a/lib/dma-direct.c > +++ b/lib/dma-direct.c > @@ -59,6 +59,9 @@ void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, > struct page *page = NULL; > void *ret; > > + /* we always manually zero the memory once we are done: */ > + gfp &= ~__GFP_ZERO; > + > /* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */ > if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS)) > gfp |= GFP_DMA; _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu ^ permalink raw reply [flat|nested] 4+ messages in thread
[parent not found: <1522249966.2593.14.camel-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>]
* dma-mapping: clear harmful GFP_* flags in common code [not found] ` <1522249966.2593.14.camel-HKixBCOQz3hWk0Htik3J/w@public.gmane.org> @ 2018-04-09 10:52 ` Alexey Brodkin 0 siblings, 0 replies; 4+ messages in thread From: Alexey Brodkin @ 2018-04-09 10:52 UTC (permalink / raw) To: stable-u79uwXL29TY76Z2rM5mHXA Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA, x86-DgEjT+Ai2ygdnm+yROfE0A, sebott-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8, linux-kernel-u79uwXL29TY76Z2rM5mHXA, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA, linux-snps-arc-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r, hch-jcswGhMUV9g Hello, May we have e89f5b370153 ("dma-mapping: Don't clear GFP_ZERO in dma_alloc_attrs") back-ported to 4.16 kernel as it fixes: 57bf5a8 ("dma-mapping: clear harmful GFP_* flags in common code"). For more info about introduced problem see this thread: http://lists.infradead.org/pipermail/linux-snps-arc/2018-March/003652.html -Alexey ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-04-09 10:52 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-03-28 13:35 tip/x86/dma fix for arc and s390 (at least) Christoph Hellwig [not found] ` <20180328133535.17302-1-hch-jcswGhMUV9g@public.gmane.org> 2018-03-28 13:35 ` [PATCH] dma-mapping: don't clear GFP_ZERO in dma_alloc_attrs Christoph Hellwig [not found] ` <20180328133535.17302-2-hch-jcswGhMUV9g@public.gmane.org> 2018-03-28 15:12 ` Evgeniy Didin [not found] ` <1522249966.2593.14.camel-HKixBCOQz3hWk0Htik3J/w@public.gmane.org> 2018-04-09 10:52 ` dma-mapping: clear harmful GFP_* flags in common code Alexey Brodkin
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