The patch titled Subject: linux/kernel.h: fix DIV_ROUND_CLOSEST to support negative dividends has been added to the -mm tree. Its filename is linux-kernelh-fix-div_round_closest-to-support-negative-dividends.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Guenter Roeck <linux@xxxxxxxxxxxx> Subject: linux/kernel.h: fix DIV_ROUND_CLOSEST to support negative dividends DIV_ROUND_CLOSEST returns a bad result for negative dividends: DIV_ROUND_CLOSEST(-2, 2) = 0 Most of the time this does not matter. However, in the hardware monitoring subsystem, DIV_ROUND_CLOSEST is sometimes used on integers which can be negative (such as temperatures). Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/kernel.h | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff -puN include/linux/kernel.h~linux-kernelh-fix-div_round_closest-to-support-negative-dividends include/linux/kernel.h --- a/include/linux/kernel.h~linux-kernelh-fix-div_round_closest-to-support-negative-dividends +++ a/include/linux/kernel.h @@ -82,10 +82,18 @@ __x - (__x % (y)); \ } \ ) + +/* + * Divide positive or negative dividend by positive divisor and round + * to closest integer. Result is undefined for negative divisors. + */ #define DIV_ROUND_CLOSEST(x, divisor)( \ { \ - typeof(divisor) __divisor = divisor; \ - (((x) + ((__divisor) / 2)) / (__divisor)); \ + typeof(x) __x = x; \ + typeof(divisor) __d = divisor; \ + (((typeof(x))-1) >= 0 || (__x) >= 0) ? \ + (((__x) + ((__d) / 2)) / (__d)) : \ + (((__x) - ((__d) / 2)) / (__d)); \ } \ ) _ Patches currently in -mm which might be from linux@xxxxxxxxxxxx are origin.patch linux-next.patch linux-kernelh-fix-div_round_closest-to-support-negative-dividends.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html