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Groups > linux.kernel > #1620865
| From | js1304@gmail.com |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v7 7/7] ARM: CMA: avoid re-mapping CMA region if CONFIG_HIGHMEM |
| Date | 2017-04-11 05:20 +0200 |
| Message-ID | <tuUvw-1sy-17@gated-at.bofh.it> (permalink) |
| References | <tuUvw-1sy-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Joonsoo Kim <iamjoonsoo.kim@lge.com> CMA region is now managed by the separate zone, ZONE_CMA, to fix many MM related problems. In this implementation, it is possible that ZONE_CMA contains two CMA regions that are on the both, lowmem and highmem, respectively. To handle this case properly, ZONE_CMA is considered as highmem. In dma_contiguous_remap(), mapping for CMA region on lowmem is cleared and remapped for DMA, but, in the new CMA implementation, remap isn't needed since the region is considered as highmem. And, remap should not be allowed since it would cause cache problems. So, this patch disables it. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> --- arch/arm/mm/dma-mapping.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 475811f..377053a 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -506,7 +506,12 @@ void __init dma_contiguous_remap(void) flush_tlb_kernel_range(__phys_to_virt(start), __phys_to_virt(end)); - iotable_init(&map, 1); + /* + * For highmem system, all the memory in CMA region will be + * considered as highmem, therefore, re-mapping isn't required. + */ + if (!IS_ENABLED(CONFIG_HIGHMEM)) + iotable_init(&map, 1); } } -- 2.7.4
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[PATCH v7 0/7] Introduce ZONE_CMA js1304@gmail.com - 2017-04-11 05:20 +0200
[PATCH v7 7/7] ARM: CMA: avoid re-mapping CMA region if CONFIG_HIGHMEM js1304@gmail.com - 2017-04-11 05:20 +0200
[PATCH v7 5/7] mm/cma: remove MIGRATE_CMA js1304@gmail.com - 2017-04-11 05:20 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Michal Hocko <mhocko@kernel.org> - 2017-04-11 20:20 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Joonsoo Kim <js1304@gmail.com> - 2017-04-12 03:40 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Michal Hocko <mhocko@kernel.org> - 2017-04-13 14:00 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Joonsoo Kim <js1304@gmail.com> - 2017-04-17 04:10 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Joonsoo Kim <js1304@gmail.com> - 2017-04-21 03:40 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Michal Hocko <mhocko@kernel.org> - 2017-04-21 09:00 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Michal Hocko <mhocko@kernel.org> - 2017-04-24 15:20 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Joonsoo Kim <js1304@gmail.com> - 2017-04-12 03:40 +0200
Re: [PATCH v7 0/7] Introduce ZONE_CMA Bob Liu <liubo95@huawei.com> - 2017-04-24 06:10 +0200
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