Re: [RFC PATCH v3 4/6] swiotlb: Add restricted DMA alloc/free support.
From: Florian Fainelli <f.fainelli@gmail.com>
Date: 2021-01-13 00:43:09
Also in:
linux-devicetree, linux-iommu, lkml, xen-devel
On 1/5/21 7:41 PM, Claire Chang wrote:
Add the functions, swiotlb_alloc and swiotlb_free to support the memory allocation from restricted DMA pool. Signed-off-by: Claire Chang <redacted> ---
[snip]
quoted hunk ↗ jump to hunk
diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 30ccbc08e229..126e9b3354d6 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c@@ -137,6 +137,11 @@ void *dma_direct_alloc(struct device *dev, size_t size, void *ret; int err; +#ifdef CONFIG_SWIOTLB + if (unlikely(dev->dma_io_tlb_mem)) + return swiotlb_alloc(dev, size, dma_handle, attrs); +#endif
While this is potentially a hot path, I am not sure of the unkikely is warranted, maybe best left as a plain conditional. -- Florian