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Diffstat (limited to 'include/linux/types.h')
-rw-r--r--include/linux/types.h18
1 files changed, 10 insertions, 8 deletions
diff --git a/include/linux/types.h b/include/linux/types.h
index 6747247e3f9f..8715287c3b1f 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -139,19 +139,21 @@ typedef unsigned long blkcnt_t;
*/
#define pgoff_t unsigned long
-/* A dma_addr_t can hold any valid DMA or bus address for the platform */
+/*
+ * A dma_addr_t can hold any valid DMA address, i.e., any address returned
+ * by the DMA API.
+ *
+ * If the DMA API only uses 32-bit addresses, dma_addr_t need only be 32
+ * bits wide. Bus addresses, e.g., PCI BARs, may be wider than 32 bits,
+ * but drivers do memory-mapped I/O to ioremapped kernel virtual addresses,
+ * so they don't care about the size of the actual bus addresses.
+ */
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
typedef u64 dma_addr_t;
#else
typedef u32 dma_addr_t;
-#endif /* dma_addr_t */
-
-#ifdef __CHECKER__
-#else
-#endif
-#ifdef __CHECK_ENDIAN__
-#else
#endif
+
typedef unsigned __bitwise__ gfp_t;
typedef unsigned __bitwise__ fmode_t;
typedef unsigned __bitwise__ oom_flags_t;