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| author | Will Deacon <will@kernel.org> | 2024-03-08 15:28:26 +0000 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2024-03-13 11:39:24 -0700 |
| commit | cbf53074a528191df82b4dba1e3d21191102255e (patch) | |
| tree | 42485da572a90860ed7d2fa59d8d1d718508e1e1 /kernel | |
| parent | 823353b7cf0ea9dfb09f5181d5fb2825d727200b (diff) | |
| download | linux-cbf53074a528191df82b4dba1e3d21191102255e.tar.gz linux-cbf53074a528191df82b4dba1e3d21191102255e.tar.bz2 linux-cbf53074a528191df82b4dba1e3d21191102255e.zip | |
swiotlb: Honour dma_alloc_coherent() alignment in swiotlb_alloc()
core-api/dma-api-howto.rst states the following properties of
dma_alloc_coherent():
| The CPU virtual address and the DMA address are both guaranteed to
| be aligned to the smallest PAGE_SIZE order which is greater than or
| equal to the requested size.
However, swiotlb_alloc() passes zero for the 'alloc_align_mask'
parameter of swiotlb_find_slots() and so this property is not upheld.
Instead, allocations larger than a page are aligned to PAGE_SIZE,
Calculate the mask corresponding to the page order suitable for holding
the allocation and pass that to swiotlb_find_slots().
Fixes: e81e99bacc9f ("swiotlb: Support aligned swiotlb buffers")
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/dma/swiotlb.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 88114433f1e6..a3645a9ae68e 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -1679,12 +1679,14 @@ struct page *swiotlb_alloc(struct device *dev, size_t size) struct io_tlb_mem *mem = dev->dma_io_tlb_mem; struct io_tlb_pool *pool; phys_addr_t tlb_addr; + unsigned int align; int index; if (!mem) return NULL; - index = swiotlb_find_slots(dev, 0, size, 0, &pool); + align = (1 << (get_order(size) + PAGE_SHIFT)) - 1; + index = swiotlb_find_slots(dev, 0, size, align, &pool); if (index == -1) return NULL; |