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Commit b4ebe606 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

dma-direct: implement complete bus_dma_mask handling 



Instead of rejecting devices with a too small bus_dma_mask we can handle
by taking the bus dma_mask into account for allocations and bounce
buffering decisions.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 7d21ee4c

include/linux/dma-direct.h

+2 −1
Original line number Diff line number Diff line
@@ -27,7 +27,8 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size) 
	if (!dev->dma_mask)

		return false;



	return addr + size - 1 <= *dev->dma_mask;

	return addr + size - 1 <=

		min_not_zero(*dev->dma_mask, dev->bus_dma_mask);

}

#endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */

kernel/dma/direct.c

+11 −10
Original line number Diff line number Diff line
@@ -44,10 +44,11 @@ check_addr(struct device *dev, dma_addr_t dma_addr, size_t size, 
			return false;

		}



		if (*dev->dma_mask >= DMA_BIT_MASK(32)) {

		if (*dev->dma_mask >= DMA_BIT_MASK(32) || dev->bus_dma_mask) {

			dev_err(dev,

				"%s: overflow %pad+%zu of device mask %llx\n",

				caller, &dma_addr, size, *dev->dma_mask);

				"%s: overflow %pad+%zu of device mask %llx bus mask %llx\n",

				caller, &dma_addr, size,

				*dev->dma_mask, dev->bus_dma_mask);

		}

		return false;

	}
@@ -66,12 +67,18 @@ u64 dma_direct_get_required_mask(struct device *dev) 
{

	u64 max_dma = phys_to_dma_direct(dev, (max_pfn - 1) << PAGE_SHIFT);



	if (dev->bus_dma_mask && dev->bus_dma_mask < max_dma)

		max_dma = dev->bus_dma_mask;



	return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;

}



static gfp_t __dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,

		u64 *phys_mask)

{

	if (dev->bus_dma_mask && dev->bus_dma_mask < dma_mask)

		dma_mask = dev->bus_dma_mask;



	if (force_dma_unencrypted())

		*phys_mask = __dma_to_phys(dev, dma_mask);

	else
@@ -88,7 +95,7 @@ static gfp_t __dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask, 
static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)

{

	return phys_to_dma_direct(dev, phys) + size - 1 <=

			dev->coherent_dma_mask;

			min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask);

}



void *dma_direct_alloc_pages(struct device *dev, size_t size,
@@ -292,12 +299,6 @@ int dma_direct_supported(struct device *dev, u64 mask) 
	if (mask < phys_to_dma(dev, DMA_BIT_MASK(32)))

		return 0;

#endif

	/*

	 * Upstream PCI/PCIe bridges or SoC interconnects may not carry

	 * as many DMA address bits as the device itself supports.

	 */

	if (dev->bus_dma_mask && mask > dev->bus_dma_mask)

		return 0;

	return 1;

}