From: Steven Rostedt I noticed the code for index_of is a creative way of finding the cache index using the compiler to optimize to a single hard coded number. But I couldn't help noticing that it uses two methods to let you know that someone used it wrong. One is at compile time (the correct way), and the other is at run time (not good). Signed-off-by: Steven Rostedt Acked-by: Manfred Spraul Signed-off-by: Pekka Enberg Signed-off-by: Andrew Morton --- mm/slab.c | 9 ++++----- 1 files changed, 4 insertions(+), 5 deletions(-) diff -puN mm/slab.c~slab-have-index_of-bug-at-compile-time mm/slab.c --- devel/mm/slab.c~slab-have-index_of-bug-at-compile-time 2006-01-15 18:40:00.000000000 -0800 +++ devel-akpm/mm/slab.c 2006-01-15 18:40:00.000000000 -0800 @@ -316,6 +316,8 @@ struct kmem_list3 __initdata initkmem_li */ static __always_inline int index_of(const size_t size) { + extern void __bad_size(void); + if (__builtin_constant_p(size)) { int i = 0; @@ -326,12 +328,9 @@ static __always_inline int index_of(cons i++; #include "linux/kmalloc_sizes.h" #undef CACHE - { - extern void __bad_size(void); - __bad_size(); - } + __bad_size(); } else - BUG(); + __bad_size(); return 0; } _