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authorVegard Nossum <vegard.nossum@gmail.com>2010-01-08 14:42:35 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-01-11 09:34:04 -0800
commite992cd9b72a18122bd5c958715623057f110793f (patch)
treef73e19fd0af4cf446ab718550acac62d021e47ee /include
parentcb5a8b2c92febbed57126e1b8416dfd7607ff03d (diff)
downloadlinux-linaro-android-e992cd9b72a18122bd5c958715623057f110793f.tar.gz
kmemcheck: make bitfield annotations truly no-ops when disabled
It turns out that even zero-sized struct members (int foo[0];) will affect the struct layout, causing us in particular to lose 4 bytes in struct sock. This patch fixes the regression in CONFIG_KMEMCHECK=n case. Reported-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/kmemcheck.h110
1 files changed, 58 insertions, 52 deletions
diff --git a/include/linux/kmemcheck.h b/include/linux/kmemcheck.h
index e880d4cf9e2..08d7dc4ddf4 100644
--- a/include/linux/kmemcheck.h
+++ b/include/linux/kmemcheck.h
@@ -36,6 +36,56 @@ int kmemcheck_hide_addr(unsigned long address);
bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size);
+/*
+ * Bitfield annotations
+ *
+ * How to use: If you have a struct using bitfields, for example
+ *
+ * struct a {
+ * int x:8, y:8;
+ * };
+ *
+ * then this should be rewritten as
+ *
+ * struct a {
+ * kmemcheck_bitfield_begin(flags);
+ * int x:8, y:8;
+ * kmemcheck_bitfield_end(flags);
+ * };
+ *
+ * Now the "flags_begin" and "flags_end" members may be used to refer to the
+ * beginning and end, respectively, of the bitfield (and things like
+ * &x.flags_begin is allowed). As soon as the struct is allocated, the bit-
+ * fields should be annotated:
+ *
+ * struct a *a = kmalloc(sizeof(struct a), GFP_KERNEL);
+ * kmemcheck_annotate_bitfield(a, flags);
+ */
+#define kmemcheck_bitfield_begin(name) \
+ int name##_begin[0];
+
+#define kmemcheck_bitfield_end(name) \
+ int name##_end[0];
+
+#define kmemcheck_annotate_bitfield(ptr, name) \
+ do { \
+ int _n; \
+ \
+ if (!ptr) \
+ break; \
+ \
+ _n = (long) &((ptr)->name##_end) \
+ - (long) &((ptr)->name##_begin); \
+ MAYBE_BUILD_BUG_ON(_n < 0); \
+ \
+ kmemcheck_mark_initialized(&((ptr)->name##_begin), _n); \
+ } while (0)
+
+#define kmemcheck_annotate_variable(var) \
+ do { \
+ kmemcheck_mark_initialized(&(var), sizeof(var)); \
+ } while (0) \
+
#else
#define kmemcheck_enabled 0
@@ -106,60 +156,16 @@ static inline bool kmemcheck_is_obj_initialized(unsigned long addr, size_t size)
return true;
}
-#endif /* CONFIG_KMEMCHECK */
-
-/*
- * Bitfield annotations
- *
- * How to use: If you have a struct using bitfields, for example
- *
- * struct a {
- * int x:8, y:8;
- * };
- *
- * then this should be rewritten as
- *
- * struct a {
- * kmemcheck_bitfield_begin(flags);
- * int x:8, y:8;
- * kmemcheck_bitfield_end(flags);
- * };
- *
- * Now the "flags_begin" and "flags_end" members may be used to refer to the
- * beginning and end, respectively, of the bitfield (and things like
- * &x.flags_begin is allowed). As soon as the struct is allocated, the bit-
- * fields should be annotated:
- *
- * struct a *a = kmalloc(sizeof(struct a), GFP_KERNEL);
- * kmemcheck_annotate_bitfield(a, flags);
- *
- * Note: We provide the same definitions for both kmemcheck and non-
- * kmemcheck kernels. This makes it harder to introduce accidental errors. It
- * is also allowed to pass NULL pointers to kmemcheck_annotate_bitfield().
- */
-#define kmemcheck_bitfield_begin(name) \
- int name##_begin[0];
-
-#define kmemcheck_bitfield_end(name) \
- int name##_end[0];
+#define kmemcheck_bitfield_begin(name)
+#define kmemcheck_bitfield_end(name)
+#define kmemcheck_annotate_bitfield(ptr, name) \
+ do { \
+ } while (0)
-#define kmemcheck_annotate_bitfield(ptr, name) \
- do { \
- int _n; \
- \
- if (!ptr) \
- break; \
- \
- _n = (long) &((ptr)->name##_end) \
- - (long) &((ptr)->name##_begin); \
- MAYBE_BUILD_BUG_ON(_n < 0); \
- \
- kmemcheck_mark_initialized(&((ptr)->name##_begin), _n); \
+#define kmemcheck_annotate_variable(var) \
+ do { \
} while (0)
-#define kmemcheck_annotate_variable(var) \
- do { \
- kmemcheck_mark_initialized(&(var), sizeof(var)); \
- } while (0) \
+#endif /* CONFIG_KMEMCHECK */
#endif /* LINUX_KMEMCHECK_H */