[PATCH] saner typechecking in generic unaligned.h

Al Viro
2007-07-17T07:50:47Z

Verify that types would match for assignment (under sizeof, so we are safe from
side effects or any code actually getting generated), then explicitly cast
everywhere to the fixed-sized types. Kills a bunch of bogus warnings about
constants being truncated (gcc, sparse), finds a pile of endianness problems
hidden by old noise (sparse).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
include/asm-generic/unaligned.h | 16 +++++++++-------
1 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/asm-generic/unaligned.h b/include/asm-generic/unaligned.h
index 09ec447..16a466e 100644
--- a/include/asm-generic/unaligned.h
+++ b/include/asm-generic/unaligned.h
@@ -18,7 +18,8 @@
#define get_unaligned(ptr) \
__get_unaligned((ptr), sizeof(*(ptr)))
#define put_unaligned(x,ptr) \
- __put_unaligned((__u64)(x), (ptr), sizeof(*(ptr)))
+ ((void)sizeof(*(ptr)=(x)),\
+ __put_unaligned((__force __u64)(x), (ptr), sizeof(*(ptr))))

/*
* This function doesn't actually exist. The idea is that when
@@ -95,21 +96,21 @@ static inline void __ustw(__u16 val, __u16 *addr)
default: \
bad_unaligned_access_length(); \
}; \
- (__typeof__(*(ptr)))val; \
+ (__force __typeof__(*(ptr)))val; \
})

#define __put_unaligned(val, ptr, size) \
-do { \
+({ \
void *__gu_p = ptr; \
switch (size) { \
case 1: \
- *(__u8 *)__gu_p = val; \
+ *(__u8 *)__gu_p = (__force __u8)val; \
break; \
case 2: \
- __ustw(val, __gu_p); \
+ __ustw((__force __u16)val, __gu_p); \
break; \
case 4: \
- __ustl(val, __gu_p); \
+ __ustl((__force __u32)val, __gu_p); \
break; \
case 8: \
__ustq(val, __gu_p); \
@@ -117,6 +118,7 @@ do { \
default: \
bad_unaligned_access_length(); \
}; \
-} while(0)
+ (void)0; \
+})

#endif /* _ASM_GENERIC_UNALIGNED_H */
--
1.5.3.GIT