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authorGuenter Roeck <linux@roeck-us.net>2012-09-18 20:42:31 -0700
committerGuenter Roeck <linux@roeck-us.net>2012-09-19 06:51:25 -0700
commit263a523d18bca306016d75f5c8d5c57c37fe52fb (patch)
tree085d8f549b1d133b00363535afe6b9e510dc9718 /include
parent521cf6489269f5b223c24857d99c779e91f42d3e (diff)
downloadlinux-263a523d18bca306016d75f5c8d5c57c37fe52fb.tar.bz2
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 <linux@roeck-us.net> Tested-by: Mauro Carvalho Chehab <mchehab@redhat.com> Acked-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/kernel.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 594b419b7d20..2451f1f7a1d9 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)); \
} \