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dma-direct: refine dma_direct_alloc zone selection 

We need to take the DMA offset and encryption bit into account when
selecting a zone.  User the opportunity to factor out the zone
selection into a helper for reuse.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
This commit is contained in:
Christoph Hellwig 2018-09-06 20:30:54 -04:00
parent a20bb05837
commit 7d21ee4c71
1 changed files with 21 additions and 10 deletions
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31
kernel/dma/direct.c
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@ -69,6 +69,22 @@ u64 dma_direct_get_required_mask(struct device *dev)
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 (force_dma_unencrypted())
*phys_mask = __dma_to_phys(dev, dma_mask);
else
*phys_mask = dma_to_phys(dev, dma_mask);
/* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */
if (*phys_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
return GFP_DMA;
if (*phys_mask <= DMA_BIT_MASK(32))
return GFP_DMA32;
return 0;
}
static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
{
return phys_to_dma_direct(dev, phys) + size - 1 <=
@ -81,17 +97,13 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size,
unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
int page_order = get_order(size);
struct page *page = NULL;
u64 phys_mask;
void *ret;
/* we always manually zero the memory once we are done: */
gfp &= ~__GFP_ZERO;
/* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */
if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))
gfp |= GFP_DMA;
if (dev->coherent_dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA))
gfp |= GFP_DMA32;
gfp |= __dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
&phys_mask);
again:
/* CMA can be used only in the context which permits sleeping */
if (gfpflags_allow_blocking(gfp)) {
@ -110,15 +122,14 @@ again:
page = NULL;
if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
dev->coherent_dma_mask < DMA_BIT_MASK(64) &&
phys_mask < DMA_BIT_MASK(64) &&
!(gfp & (GFP_DMA32 | GFP_DMA))) {
gfp |= GFP_DMA32;
goto again;
}
if (IS_ENABLED(CONFIG_ZONE_DMA) &&
dev->coherent_dma_mask < DMA_BIT_MASK(32) &&
!(gfp & GFP_DMA)) {
phys_mask < DMA_BIT_MASK(32) && !(gfp & GFP_DMA)) {
gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
goto again;
}