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| author | Borislav Petkov <bbpetkov@yahoo.de> | 2007-05-06 14:49:17 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-07 12:12:52 -0700 |
| commit | 9490991482a2091a828d997adbc088e24c310a4d (patch) | |
| tree | dcdd9febee63e82cd792250a8a4c4dd8e6aab4be | |
| parent | a8127717cb24be7b8827a8d9e0ddbfde6b392146 (diff) | |
| download | linux-3.10-9490991482a2091a828d997adbc088e24c310a4d.tar.gz linux-3.10-9490991482a2091a828d997adbc088e24c310a4d.tar.bz2 linux-3.10-9490991482a2091a828d997adbc088e24c310a4d.zip | |
Add unitialized_var() macro for suppressing gcc warnings
Introduce a macro for suppressing gcc from generating a warning about a
probable uninitialized state of a variable.
Example:
- spinlock_t *ptl;
+ spinlock_t *uninitialized_var(ptl);
Not a happy solution, but those warnings are obnoxious.
- Using the usual pointlessly-set-it-to-zero approach wastes several
bytes of text.
- Using a macro means we can (hopefully) do something else if gcc changes
cause the `x = x' hack to stop working
- Using a macro means that people who are worried about hiding true bugs
can easily turn it off.
Signed-off-by: Borislav Petkov <bbpetkov@yahoo.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/compiler-gcc3.h | 6 | ||||
| -rw-r--r-- | include/linux/compiler-gcc4.h | 6 | ||||
| -rw-r--r-- | include/linux/compiler-intel.h | 2 | ||||
| -rw-r--r-- | mm/memory.c | 2 |
4 files changed, 15 insertions, 1 deletions
diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h index 1698b845761..ecd621fd27d 100644 --- a/include/linux/compiler-gcc3.h +++ b/include/linux/compiler-gcc3.h @@ -13,4 +13,10 @@ #define __must_check __attribute__((warn_unused_result)) #endif +/* + * A trick to suppress uninitialized variable warning without generating any + * code + */ +#define uninitialized_var(x) x = x + #define __always_inline inline __attribute__((always_inline)) diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index 6f5cc6f0e7a..fd0cc7c4a63 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -16,3 +16,9 @@ #define __must_check __attribute__((warn_unused_result)) #define __compiler_offsetof(a,b) __builtin_offsetof(a,b) #define __always_inline inline __attribute__((always_inline)) + +/* + * A trick to suppress uninitialized variable warning without generating any + * code + */ +#define uninitialized_var(x) x = x diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h index 1d1c3ceaff4..a436eea4391 100644 --- a/include/linux/compiler-intel.h +++ b/include/linux/compiler-intel.h @@ -22,3 +22,5 @@ (typeof(ptr)) (__ptr + (off)); }) #endif + +#define uninitialized_var(x) x diff --git a/mm/memory.c b/mm/memory.c index c252aae544e..1d647ab0ee7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1455,7 +1455,7 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, pte_t *pte; int err; struct page *pmd_page; - spinlock_t *ptl = ptl; /* Suppress gcc warning */ + spinlock_t *uninitialized_var(ptl); pte = (mm == &init_mm) ? pte_alloc_kernel(pmd, addr) : |