From 263a523d18bca306016d75f5c8d5c57c37fe52fb Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Tue, 18 Sep 2012 20:42:31 -0700 Subject: linux/kernel.h: Fix warning seen with W=1 due to change in DIV_ROUND_CLOSEST After commit b6d86d3d (Fix DIV_ROUND_CLOSEST to support negative dividends), the following warning is seen if the kernel is compiled with W=1 (-Wextra): warning: comparison of unsigned expression >= 0 is always true The warning is due to the test '((typeof(x))-1) >= 0', which is used to detect if the variable type is unsigned. Research on the web suggests that the warning disappears if '>' instead of '>=' is used for the comparison. Tests after changing the macro along that line show that the warning is gone, and that the result is still correct: i=-4: DIV_ROUND_CLOSEST(i, 2)=-2 i=-3: DIV_ROUND_CLOSEST(i, 2)=-2 i=-2: DIV_ROUND_CLOSEST(i, 2)=-1 i=-1: DIV_ROUND_CLOSEST(i, 2)=-1 i=0: DIV_ROUND_CLOSEST(i, 2)=0 i=1: DIV_ROUND_CLOSEST(i, 2)=1 i=2: DIV_ROUND_CLOSEST(i, 2)=1 i=3: DIV_ROUND_CLOSEST(i, 2)=2 i=4: DIV_ROUND_CLOSEST(i, 2)=2 Code size is the same as before. Signed-off-by: Guenter Roeck Tested-by: Mauro Carvalho Chehab Acked-by: Jean Delvare --- include/linux/kernel.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 594b419b7d2..2451f1f7a1d 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -91,7 +91,7 @@ { \ typeof(x) __x = x; \ typeof(divisor) __d = divisor; \ - (((typeof(x))-1) >= 0 || (__x) >= 0) ? \ + (((typeof(x))-1) > 0 || (__x) > 0) ? \ (((__x) + ((__d) / 2)) / (__d)) : \ (((__x) - ((__d) / 2)) / (__d)); \ } \ -- cgit v1.2.3