[PATCH 09/22] swiotlb: refactor coherent buffer freeing

Christoph Hellwig
2018-01-10T08:10:11Z

Factor out a new swiotlb_free_buffer helper that checks if an address
is allocated from the swiotlb bounce buffer, and if yes frees it.

This allows to simplify the swiotlb_free implemenation that uses
dma_direct_free to free the non-bounce buffer allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
lib/swiotlb.c | 35 +++++++++++++++++++++--------------
1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 539fd1099ba9..1a147f1354a1 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -780,22 +780,31 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
}
EXPORT_SYMBOL(swiotlb_alloc_coherent);

+static bool swiotlb_free_buffer(struct device *dev, size_t size,
+ dma_addr_t dma_addr)
+{
+ phys_addr_t phys_addr = dma_to_phys(dev, dma_addr);
+
+ WARN_ON_ONCE(irqs_disabled());
+
+ if (!is_swiotlb_buffer(phys_addr))
+ return false;
+
+ /*
+ * DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single.
+ * DMA_ATTR_SKIP_CPU_SYNC is optional.
+ */
+ swiotlb_tbl_unmap_single(dev, phys_addr, size, DMA_TO_DEVICE,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ return true;
+}
+
void
swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
dma_addr_t dev_addr)
{
- phys_addr_t paddr = dma_to_phys(hwdev, dev_addr);
-
- WARN_ON(irqs_disabled());
- if (!is_swiotlb_buffer(paddr))
+ if (!swiotlb_free_buffer(hwdev, size, dev_addr))
free_pages((unsigned long)vaddr, get_order(size));
- else
- /*
- * DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single.
- * DMA_ATTR_SKIP_CPU_SYNC is optional.
- */
- swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE,
- DMA_ATTR_SKIP_CPU_SYNC);
}
EXPORT_SYMBOL(swiotlb_free_coherent);

@@ -1110,9 +1119,7 @@ void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
void swiotlb_free(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_addr, unsigned long attrs)
{
- if (is_swiotlb_buffer(dma_to_phys(dev, dma_addr)))
- swiotlb_free_coherent(dev, size, vaddr, dma_addr);
- else
+ if (!swiotlb_free_buffer(dev, size, dma_addr))
dma_direct_free(dev, size, vaddr, dma_addr, attrs);
}

--
2.14.2