diff options
| author | Nicolas Saenz Julienne <nsaenzjulienne@suse.de> | 2019-10-14 20:31:03 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2019-11-01 09:41:18 +0000 |
| commit | 8b5369ea580964dbc982781bfb9fb93459fc5e8d (patch) | |
| tree | 55f4d7308e5fb1f4c5df396e637ba08bfa2daf46 /kernel/dma | |
| parent | 4686da5140c18c84ca01a8ab994571d832c63398 (diff) | |
| download | lwn-8b5369ea580964dbc982781bfb9fb93459fc5e8d.tar.gz lwn-8b5369ea580964dbc982781bfb9fb93459fc5e8d.zip | |
dma/direct: turn ARCH_ZONE_DMA_BITS into a variable
Some architectures, notably ARM, are interested in tweaking this
depending on their runtime DMA addressing limitations.
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'kernel/dma')
| -rw-r--r-- | kernel/dma/direct.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 8402b29c280f..0b67c04e531b 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -16,12 +16,11 @@ #include <linux/swiotlb.h> /* - * Most architectures use ZONE_DMA for the first 16 Megabytes, but - * some use it for entirely different regions: + * Most architectures use ZONE_DMA for the first 16 Megabytes, but some use it + * it for entirely different regions. In that case the arch code needs to + * override the variable below for dma-direct to work properly. */ -#ifndef ARCH_ZONE_DMA_BITS -#define ARCH_ZONE_DMA_BITS 24 -#endif +unsigned int zone_dma_bits __ro_after_init = 24; static void report_addr(struct device *dev, dma_addr_t dma_addr, size_t size) { @@ -69,7 +68,7 @@ static gfp_t __dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask, * Note that GFP_DMA32 and GFP_DMA are no ops without the corresponding * zones. */ - if (*phys_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS)) + if (*phys_mask <= DMA_BIT_MASK(zone_dma_bits)) return GFP_DMA; if (*phys_mask <= DMA_BIT_MASK(32)) return GFP_DMA32; @@ -395,7 +394,7 @@ int dma_direct_supported(struct device *dev, u64 mask) u64 min_mask; if (IS_ENABLED(CONFIG_ZONE_DMA)) - min_mask = DMA_BIT_MASK(ARCH_ZONE_DMA_BITS); + min_mask = DMA_BIT_MASK(zone_dma_bits); else min_mask = DMA_BIT_MASK(32); |