Revert "swiotlb: rework "fix info leak with DMA_FROM_DEVICE""

[linux-2.6-microblaze.git] / include / linux / dma-mapping.h

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index dca2b13..6150d11 100644 (file)
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -61,6 +61,14 @@
  */
 #define DMA_ATTR_PRIVILEGED            (1UL << 9)
 
+/*
+ * This is a hint to the DMA-mapping subsystem that the device is expected
+ * to overwrite the entire mapped size, thus the caller does not require any
+ * of the previous buffer contents to be preserved. This allows
+ * bounce-buffering implementations to optimise DMA_FROM_DEVICE transfers.
+ */
+#define DMA_ATTR_OVERWRITE             (1UL << 10)
+
 /*
  * A dma_addr_t can hold any valid DMA or bus address for the platform.  It can
  * be given to a device to use as a DMA source or target.  It is specific to a