dma-mapping: replace zone_dma_bits by zone_dma_limit

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The hardware DMA limit might not be power of 2. When RAM range starts
above 0, say 4GB, DMA limit of 30 bits should end at 5GB.  A single high
bit can not encode this limit.

Use a plain  address for the DMA zone limit instead.

Since the DMA zone can now potentially span beyond 4GB physical limit of
DMA32, make sure to use DMA zone for GFP_DMA32 allocations in that case.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Co-developed-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Petr Tesarik <ptesarik@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

...

This commit is contained in:

Catalin Marinas 2024-08-11 10:09:35 +03:00 • committed by Christoph Hellwig

parent fa3c109a6d

commit ba0fb44aed

7 changed files with 29 additions and 26 deletions

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30

arch/arm64/mm/init.c

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5

arch/powerpc/mm/mem.c

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2

arch/s390/mm/init.c

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2

include/linux/dma-direct.h

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6

kernel/dma/direct.c

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4

kernel/dma/pool.c

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kernel/dma/swiotlb.c

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