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author | Guenter Roeck <linux@roeck-us.net> | 2012-09-19 03:42:31 (GMT) |
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committer | Guenter Roeck <linux@roeck-us.net> | 2012-09-19 13:51:25 (GMT) |
commit | 263a523d18bca306016d75f5c8d5c57c37fe52fb (patch) | |
tree | 085d8f549b1d133b00363535afe6b9e510dc9718 /Documentation/driver-model | |
parent | 521cf6489269f5b223c24857d99c779e91f42d3e (diff) | |
download | linux-fsl-qoriq-263a523d18bca306016d75f5c8d5c57c37fe52fb.tar.xz |
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 'Documentation/driver-model')
0 files changed, 0 insertions, 0 deletions