From 8b5369ea580964dbc982781bfb9fb93459fc5e8d Mon Sep 17 00:00:00 2001 From: Nicolas Saenz Julienne Date: Mon, 14 Oct 2019 20:31:03 +0200 Subject: 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 Signed-off-by: Nicolas Saenz Julienne Signed-off-by: Catalin Marinas --- kernel/dma/direct.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'kernel/dma') 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 /* - * 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); -- cgit v1.2.3-59-g8ed1b