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dma-direct: simplify the use atomic pool logic in dma_direct_alloc

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The logic in dma_direct_alloc when to use the atomic pool vs remapping
grew a bit unreadable.  Consolidate it into a single check, and clean
up the set_uncached vs remap logic a bit as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
This commit is contained in:
Christoph Hellwig 2023-10-06 15:13:34 +02:00
parent 2c8ed1b960
commit b1da46d70e
1 changed files with 10 additions and 15 deletions
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25
kernel/dma/direct.c
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@ -234,27 +234,22 @@ void *dma_direct_alloc(struct device *dev, size_t size,
dma_handle);
/*
* Otherwise remap if the architecture is asking for it. But
* given that remapping memory is a blocking operation we'll
* instead have to dip into the atomic pools.
* Otherwise we require the architecture to either be able to
* mark arbitrary parts of the kernel direct mapping uncached,
* or remapped it uncached.
*/
set_uncached = IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED);
remap = IS_ENABLED(CONFIG_DMA_DIRECT_REMAP);
if (remap) {
if (dma_direct_use_pool(dev, gfp))
return dma_direct_alloc_from_pool(dev, size,
dma_handle, gfp);
} else {
if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED))
return NULL;
set_uncached = true;
}
if (!set_uncached && !remap)
return NULL;
}
/*
* Decrypting memory may block, so allocate the memory from the atomic
* pools if we can't block.
* Remapping or decrypting memory may block, allocate the memory from
* the atomic pools instead if we aren't allowed block.
*/
if (force_dma_unencrypted(dev) && dma_direct_use_pool(dev, gfp))
if ((remap || force_dma_unencrypted(dev)) &&
dma_direct_use_pool(dev, gfp))
return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
/* we always manually zero the memory once we are done */