endian: Always evaluate arguments.

Changeset 7fa897b ("ide: trivial sparse annotations") created an IDE bootup regression on big-endian systems. In drivers/ide/ide-iops.c, function ide_fixstring() we now have the loop: for (p = end ; p != s;) be16_to_cpus((u16 *)(p -= 2)); which will never terminate on big-endian because in such a configuration be16_to_cpus() evaluates to "do { } while (0)" Therefore, always evaluate the arguments to nop endian transformation operations. Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
mna · Jul 25, 2008 · 3d6f4a2 · 3d6f4a2
1 parent 43de804
commit 3d6f4a2
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Showing 2 changed files with 12 additions and 12 deletions.
diff --git a/include/linux/byteorder/big_endian.h b/include/linux/byteorder/big_endian.h
@@ -94,12 +94,12 @@ static inline __u16 __be16_to_cpup(const __be16 *p)
 #define __le32_to_cpus(x) __swab32s((x))
 #define __cpu_to_le16s(x) __swab16s((x))
 #define __le16_to_cpus(x) __swab16s((x))
-#define __cpu_to_be64s(x) do {} while (0)
-#define __be64_to_cpus(x) do {} while (0)
-#define __cpu_to_be32s(x) do {} while (0)
-#define __be32_to_cpus(x) do {} while (0)
-#define __cpu_to_be16s(x) do {} while (0)
-#define __be16_to_cpus(x) do {} while (0)
+#define __cpu_to_be64s(x) do { (void)(x); } while (0)
+#define __be64_to_cpus(x) do { (void)(x); } while (0)
+#define __cpu_to_be32s(x) do { (void)(x); } while (0)
+#define __be32_to_cpus(x) do { (void)(x); } while (0)
+#define __cpu_to_be16s(x) do { (void)(x); } while (0)
+#define __be16_to_cpus(x) do { (void)(x); } while (0)
 
 #ifdef __KERNEL__
 #include <linux/byteorder/generic.h>

diff --git a/include/linux/byteorder/little_endian.h b/include/linux/byteorder/little_endian.h
@@ -88,12 +88,12 @@ static inline __u16 __be16_to_cpup(const __be16 *p)
 {
 	return __swab16p((__u16 *)p);
 }
-#define __cpu_to_le64s(x) do {} while (0)
-#define __le64_to_cpus(x) do {} while (0)
-#define __cpu_to_le32s(x) do {} while (0)
-#define __le32_to_cpus(x) do {} while (0)
-#define __cpu_to_le16s(x) do {} while (0)
-#define __le16_to_cpus(x) do {} while (0)
+#define __cpu_to_le64s(x) do { (void)(x); } while (0)
+#define __le64_to_cpus(x) do { (void)(x); } while (0)
+#define __cpu_to_le32s(x) do { (void)(x); } while (0)
+#define __le32_to_cpus(x) do { (void)(x); } while (0)
+#define __cpu_to_le16s(x) do { (void)(x); } while (0)
+#define __le16_to_cpus(x) do { (void)(x); } while (0)
 #define __cpu_to_be64s(x) __swab64s((x))
 #define __be64_to_cpus(x) __swab64s((x))
 #define __cpu_to_be32s(x) __swab32s((x))