Messages in this thread Patch in this message | | | Subject | Re: [PATCH 2/5] dma-direct: add an explicit dma_direct_get_required_mask | From | Robin Murphy <> | Date | Thu, 27 Sep 2018 15:12:25 +0100 |
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On 20/09/18 19:52, Christoph Hellwig wrote: > This is somewhat modelled after the powerpc version, and differs from > the legacy fallback in use fls64 instead of pointlessly splitting up the > address into low and high dwords and in that it takes (__)phys_to_dma > into account. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > include/linux/dma-direct.h | 1 + > kernel/dma/direct.c | 21 ++++++++++++++++++--- > 2 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h > index 86a59ba5a7f3..b79496d8c75b 100644 > --- a/include/linux/dma-direct.h > +++ b/include/linux/dma-direct.h > @@ -55,6 +55,7 @@ static inline void dma_mark_clean(void *addr, size_t size) > } > #endif /* CONFIG_ARCH_HAS_DMA_MARK_CLEAN */ > > +u64 dma_direct_get_required_mask(struct device *dev); > void *dma_direct_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, > gfp_t gfp, unsigned long attrs); > void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index c954f0a6dc62..81b73a5bba54 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -53,11 +53,25 @@ check_addr(struct device *dev, dma_addr_t dma_addr, size_t size, > return true; > } > > +static inline dma_addr_t phys_to_dma_direct(struct device *dev, > + phys_addr_t phys) > +{ > + if (force_dma_unencrypted()) > + return __phys_to_dma(dev, phys); > + return phys_to_dma(dev, phys); > +} > + > +u64 dma_direct_get_required_mask(struct device *dev) > +{ > + u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT); > + > + return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
I think that may as well just use __fls64() - it seems reasonable to assume max_dma > 0. Otherwise,
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> +} > + > static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) > { > - dma_addr_t addr = force_dma_unencrypted() ? > - __phys_to_dma(dev, phys) : phys_to_dma(dev, phys); > - return addr + size - 1 <= dev->coherent_dma_mask; > + return phys_to_dma_direct(dev, phys) + size - 1 <= > + dev->coherent_dma_mask; > } > > void *dma_direct_alloc_pages(struct device *dev, size_t size, > @@ -296,6 +310,7 @@ const struct dma_map_ops dma_direct_ops = { > .unmap_page = dma_direct_unmap_page, > .unmap_sg = dma_direct_unmap_sg, > #endif > + .get_required_mask = dma_direct_get_required_mask, > .dma_supported = dma_direct_supported, > .mapping_error = dma_direct_mapping_error, > .cache_sync = arch_dma_cache_sync, >
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