From 0c43288a7366cda0a15750e8fdb6a81c83a6c9a7 Mon Sep 17 00:00:00 2001 From: Andrei Warkentin Date: Wed, 30 Nov 2011 15:11:39 +1100 Subject: [PATCH] include/log2.h: fix rounddown_pow_of_two(1) 1 is a power of two, therefore rounddown_pow_of_two(1) should return 1. It does in case the argument is a variable but in case it's a constant it behaves wrong and returns 0. Probably nobody ever did it so this was never noticed, however net/drivers/vmxnet3 with latest GCC does and breaks on unicpu systems. This is similar to Rolf's patch to roundup_pow_of_two(1). Cc: Rolf Eike Beer Reviewed-by: Jesper Juhl Signed-off-by: Andrei Warkentin Signed-off-by: Andrew Morton --- include/linux/log2.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/log2.h b/include/linux/log2.h index 25b808631cd9..ccda848411c8 100644 --- a/include/linux/log2.h +++ b/include/linux/log2.h @@ -185,7 +185,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n) #define rounddown_pow_of_two(n) \ ( \ __builtin_constant_p(n) ? ( \ - (n == 1) ? 0 : \ + (n == 1) ? 1 : \ (1UL << ilog2(n))) : \ __rounddown_pow_of_two(n) \ ) -- 2.39.5