Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756608AbYCMBCj (ORCPT ); Wed, 12 Mar 2008 21:02:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755282AbYCMBBm (ORCPT ); Wed, 12 Mar 2008 21:01:42 -0400 Received: from scrub.xs4all.nl ([194.109.195.176]:53902 "EHLO scrub.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753819AbYCMBBk (ORCPT ); Wed, 12 Mar 2008 21:01:40 -0400 Message-Id: <20080313004902.866970953@linux-m68k.org> References: <20080313002235.351414762@linux-m68k.org> User-Agent: quilt/0.46-1 Date: Thu, 13 Mar 2008 01:22:37 +0100 From: zippel@linux-m68k.org To: linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org Subject: [PATCH 2/4] convert a few do_div user Content-Disposition: inline; filename=div64_2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4996 Lines: 164 This converts a few users of do_div to div_[su]64 and this demonstrates nicely how it can reduce some expressions to one-liners. Signed-off-by: Roman Zippel --- kernel/time.c | 29 +++++++++-------------------- kernel/time/ntp.c | 25 ++++++------------------- 2 files changed, 15 insertions(+), 39 deletions(-) Index: linux-2.6/kernel/time.c =================================================================== --- linux-2.6.orig/kernel/time.c 2008-03-11 17:15:14.000000000 +0100 +++ linux-2.6/kernel/time.c 2008-03-12 21:21:20.000000000 +0100 @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -585,9 +586,7 @@ clock_t jiffies_to_clock_t(long x) return x / (HZ / USER_HZ); # endif #else - u64 tmp = (u64)x * TICK_NSEC; - do_div(tmp, (NSEC_PER_SEC / USER_HZ)); - return (long)tmp; + return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ); #endif } EXPORT_SYMBOL(jiffies_to_clock_t); @@ -599,16 +598,12 @@ unsigned long clock_t_to_jiffies(unsigne return ~0UL; return x * (HZ / USER_HZ); #else - u64 jif; - /* Don't worry about loss of precision here .. */ if (x >= ~0UL / HZ * USER_HZ) return ~0UL; /* .. but do try to contain it here */ - jif = x * (u64) HZ; - do_div(jif, USER_HZ); - return jif; + return div_u64((u64)x * HZ, USER_HZ); #endif } EXPORT_SYMBOL(clock_t_to_jiffies); @@ -617,10 +612,9 @@ u64 jiffies_64_to_clock_t(u64 x) { #if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0 # if HZ < USER_HZ - x *= USER_HZ; - do_div(x, HZ); + x = div_u64(x * USER_HZ, HZ); # elif HZ > USER_HZ - do_div(x, HZ / USER_HZ); + x = div_u64(x, HZ / USER_HZ); # else /* Nothing to do */ # endif @@ -630,8 +624,7 @@ u64 jiffies_64_to_clock_t(u64 x) * but even this doesn't overflow in hundreds of years * in 64 bits, so.. */ - x *= TICK_NSEC; - do_div(x, (NSEC_PER_SEC / USER_HZ)); + x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ)); #endif return x; } @@ -640,21 +633,17 @@ EXPORT_SYMBOL(jiffies_64_to_clock_t); u64 nsec_to_clock_t(u64 x) { #if (NSEC_PER_SEC % USER_HZ) == 0 - do_div(x, (NSEC_PER_SEC / USER_HZ)); + return div_u64(x, NSEC_PER_SEC / USER_HZ); #elif (USER_HZ % 512) == 0 - x *= USER_HZ/512; - do_div(x, (NSEC_PER_SEC / 512)); + return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512); #else /* * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024, * overflow after 64.99 years. * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ... */ - x *= 9; - do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2)) / - USER_HZ)); + return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ); #endif - return x; } #if (BITS_PER_LONG < 64) Index: linux-2.6/kernel/time/ntp.c =================================================================== --- linux-2.6.orig/kernel/time/ntp.c 2008-03-11 17:15:14.000000000 +0100 +++ linux-2.6/kernel/time/ntp.c 2008-03-12 21:21:20.000000000 +0100 @@ -15,7 +15,7 @@ #include #include #include -#include +#include #include /* @@ -53,10 +53,8 @@ static void ntp_update_frequency(void) tick_length_base = second_length; - do_div(second_length, HZ); - tick_nsec = second_length >> TICK_LENGTH_SHIFT; - - do_div(tick_length_base, NTP_INTERVAL_FREQ); + tick_nsec = div_u64(second_length, HZ) >> TICK_LENGTH_SHIFT; + tick_length_base = div_u64(tick_length_base, NTP_INTERVAL_FREQ); } /** @@ -237,7 +235,7 @@ static inline void notify_cmos_timer(voi int do_adjtimex(struct timex *txc) { long mtemp, save_adjust, rem; - s64 freq_adj, temp64; + s64 freq_adj; int result; /* In order to modify anything, you gotta be super-user! */ @@ -342,19 +340,8 @@ int do_adjtimex(struct timex *txc) freq_adj = time_offset * mtemp; freq_adj = shift_right(freq_adj, time_constant * 2 + (SHIFT_PLL + 2) * 2 - SHIFT_NSEC); - if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) { - u64 utemp64; - temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL); - if (time_offset < 0) { - utemp64 = -temp64; - do_div(utemp64, mtemp); - freq_adj -= utemp64; - } else { - utemp64 = temp64; - do_div(utemp64, mtemp); - freq_adj += utemp64; - } - } + if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) + freq_adj += div_s64(time_offset << (SHIFT_NSEC - SHIFT_FLL), mtemp); freq_adj += time_freq; freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC); time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC); -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/