ARM: use flush_kernel_dcache_area() for dmabounce

After copying data from the bounce buffer to the real buffer, use
flush_kernel_dcache_page() to ensure that data is written back in
manner coherent with future userspace mappings.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 4 insertions, 8 deletions

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 5a375e5fef21..bc90364a96c7 100644
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -308,15 +308,11 @@ static inline void unmap_single(struct device *dev, dma_addr_t dma_addr,
                         memcpy(ptr, buf->safe, size);
 
                         /*
-                         * DMA buffers must have the same cache properties
-                         * as if they were really used for DMA - which means
-                         * data must be written back to RAM.  Note that
-                         * we don't use dmac_flush_range() here for the
-                         * bidirectional case because we know the cache
-                         * lines will be coherent with the data written.
+                         * Since we may have written to a page cache page,
+                         * we need to ensure that the data will be coherent
+                         * with user mappings.
                          */
-                        dmac_clean_range(ptr, ptr + size);
-                        outer_clean_range(__pa(ptr), __pa(ptr) + size);
+                        __cpuc_flush_kernel_dcache_area(ptr, size);
                 }
                 free_safe_buffer(dev->archdata.dmabounce, buf);
         }