From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965717AbbLRVkR (ORCPT ); Fri, 18 Dec 2015 16:40:17 -0500 Received: from mail-pf0-f175.google.com ([209.85.192.175]:33699 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965682AbbLRVjc (ORCPT ); Fri, 18 Dec 2015 16:39:32 -0500 From: John Stultz To: lkml Cc: DengChao , Thomas Gleixner , Ingo Molnar , Miroslav Lichvar , Prarit Bhargava , Richard Cochran , John Stultz Subject: [PATCH 10/11] ntp: Fix second_overflow's input parameter type to be 64bits Date: Fri, 18 Dec 2015 13:39:15 -0800 Message-Id: <1450474756-10144-11-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1450474756-10144-1-git-send-email-john.stultz@linaro.org> References: <1450474756-10144-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: DengChao The function "second_overflow" uses "unsign long" as its input parameter type which will overflow after year 2106 on 32bit systems. Thus this patch replaces it with time64_t type. While the 64-bit division is expensive, "next_ntp_leap_sec" has been calculated already, so we can just re-use it in the TIME_INS/DEL cases, allowing one expensive division per leapsecond instead of re-doing the divsion once a second after the leap flag has been set. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Miroslav Lichvar Cc: Prarit Bhargava Cc: Richard Cochran Signed-off-by: DengChao [jstultz: Tweaked commit message] Signed-off-by: John Stultz --- kernel/time/ntp.c | 16 +++++++++------- kernel/time/ntp_internal.h | 2 +- 2 files changed, 10 insertions(+), 8 deletions(-) diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index e947bfd..36f2ca0 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "ntp_internal.h" #include "timekeeping_internal.h" @@ -394,10 +395,11 @@ ktime_t ntp_get_next_leap(void) * * Also handles leap second processing, and returns leap offset */ -int second_overflow(unsigned long secs) +int second_overflow(time64_t secs) { s64 delta; int leap = 0; + s32 rem; /* * Leap second processing. If in leap-insert state at the end of the @@ -408,19 +410,19 @@ int second_overflow(unsigned long secs) case TIME_OK: if (time_status & STA_INS) { time_state = TIME_INS; - ntp_next_leap_sec = secs + SECS_PER_DAY - - (secs % SECS_PER_DAY); + div_s64_rem(secs, SECS_PER_DAY, &rem); + ntp_next_leap_sec = secs + SECS_PER_DAY - rem; } else if (time_status & STA_DEL) { time_state = TIME_DEL; - ntp_next_leap_sec = secs + SECS_PER_DAY - - ((secs+1) % SECS_PER_DAY); + div_s64_rem(secs + 1, SECS_PER_DAY, &rem); + ntp_next_leap_sec = secs + SECS_PER_DAY - rem; } break; case TIME_INS: if (!(time_status & STA_INS)) { ntp_next_leap_sec = TIME64_MAX; time_state = TIME_OK; - } else if (secs % SECS_PER_DAY == 0) { + } else if (secs == ntp_next_leap_sec) { leap = -1; time_state = TIME_OOP; printk(KERN_NOTICE @@ -431,7 +433,7 @@ int second_overflow(unsigned long secs) if (!(time_status & STA_DEL)) { ntp_next_leap_sec = TIME64_MAX; time_state = TIME_OK; - } else if ((secs + 1) % SECS_PER_DAY == 0) { + } else if (secs == ntp_next_leap_sec) { leap = 1; ntp_next_leap_sec = TIME64_MAX; time_state = TIME_WAIT; diff --git a/kernel/time/ntp_internal.h b/kernel/time/ntp_internal.h index af92447..d8a7c11 100644 --- a/kernel/time/ntp_internal.h +++ b/kernel/time/ntp_internal.h @@ -6,7 +6,7 @@ extern void ntp_clear(void); /* Returns how long ticks are at present, in ns / 2^NTP_SCALE_SHIFT. */ extern u64 ntp_tick_length(void); extern ktime_t ntp_get_next_leap(void); -extern int second_overflow(unsigned long secs); +extern int second_overflow(time64_t secs); extern int ntp_validate_timex(struct timex *); extern int __do_adjtimex(struct timex *, struct timespec64 *, s32 *); extern void __hardpps(const struct timespec64 *, const struct timespec64 *); -- 1.9.1