[PATCH 49/67] swiotlb: refactor coherent buffer freeing

[Christoph Hellwig <hch@lst.de>]

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 a14fff30ee9d..adb4dd0091fa 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -773,22 +773,31 @@ 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);
 
@@ -1103,9 +1112,7 @@ 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