From 0df1c9868c3a1916198ee09c323ca5932a0b8a11 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 10 Jul 2019 15:01:53 +0200 Subject: [PATCH] timekeeping/vsyscall: Use __iter_div_u64_rem() On 32-bit x86 when building with clang-9, the 'division' loop gets turned back into an inefficient division that causes a link error: kernel/time/vsyscall.o: In function `update_vsyscall': vsyscall.c:(.text+0xe3): undefined reference to `__udivdi3' Use the existing __iter_div_u64_rem() function which is used to address the same issue in other places. Fixes: 44f57d788e7d ("timekeeping: Provide a generic update_vsyscall() implementation") Signed-off-by: Arnd Bergmann Signed-off-by: Thomas Gleixner Reviewed-by: Nathan Chancellor Tested-by: Nathan Chancellor Link: https://lkml.kernel.org/r/20190710130206.1670830-1-arnd@arndb.de --- kernel/time/vsyscall.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c index a808931..8cf3596a 100644 --- a/kernel/time/vsyscall.c +++ b/kernel/time/vsyscall.c @@ -104,11 +104,7 @@ void update_vsyscall(struct timekeeper *tk) vdso_ts->sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; nsec = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift; nsec = nsec + tk->wall_to_monotonic.tv_nsec; - while (nsec >= NSEC_PER_SEC) { - nsec = nsec - NSEC_PER_SEC; - vdso_ts->sec++; - } - vdso_ts->nsec = nsec; + vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec); if (__arch_use_vsyscall(vdata)) update_vdso_data(vdata, tk); -- 2.7.4