remove div_long_long_rem
Roman Zippel [Thu, 1 May 2008 11:34:31 +0000 (04:34 -0700)]
x86 is the only arch right now, which provides an optimized for
div_long_long_rem and it has the downside that one has to be very careful that
the divide doesn't overflow.

The API is a little akward, as the arguments for the unsigned divide are
signed.  The signed version also doesn't handle a negative divisor and
produces worse code on 64bit archs.

There is little incentive to keep this API alive, so this converts the few
users to the new API.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/mips/kernel/binfmt_elfn32.c
arch/mips/kernel/binfmt_elfo32.c
drivers/char/mmtimer.c
include/asm-x86/div64.h
include/linux/calc64.h [deleted file]
include/linux/jiffies.h
kernel/posix-cpu-timers.c
kernel/time.c
kernel/time/ntp.c
mm/slub.c

index 77db347..9fdd8bc 100644 (file)
@@ -54,6 +54,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
 #include <linux/module.h>
 #include <linux/elfcore.h>
 #include <linux/compat.h>
+#include <linux/math64.h>
 
 #define elf_prstatus elf_prstatus32
 struct elf_prstatus32
@@ -102,8 +103,8 @@ jiffies_to_compat_timeval(unsigned long jiffies, struct compat_timeval *value)
         * one divide.
         */
        u64 nsec = (u64)jiffies * TICK_NSEC;
-       long rem;
-       value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &rem);
+       u32 rem;
+       value->tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
        value->tv_usec = rem / NSEC_PER_USEC;
 }
 
index 08f4cd7..e1333d7 100644 (file)
@@ -56,6 +56,7 @@ typedef elf_fpreg_t elf_fpregset_t[ELF_NFPREG];
 #include <linux/module.h>
 #include <linux/elfcore.h>
 #include <linux/compat.h>
+#include <linux/math64.h>
 
 #define elf_prstatus elf_prstatus32
 struct elf_prstatus32
@@ -104,8 +105,8 @@ jiffies_to_compat_timeval(unsigned long jiffies, struct compat_timeval *value)
         * one divide.
         */
        u64 nsec = (u64)jiffies * TICK_NSEC;
-       long rem;
-       value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &rem);
+       u32 rem;
+       value->tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
        value->tv_usec = rem / NSEC_PER_USEC;
 }
 
index d83db5d..192961f 100644 (file)
@@ -30,6 +30,8 @@
 #include <linux/miscdevice.h>
 #include <linux/posix-timers.h>
 #include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/math64.h>
 
 #include <asm/uaccess.h>
 #include <asm/sn/addrs.h>
@@ -472,8 +474,8 @@ static int sgi_clock_get(clockid_t clockid, struct timespec *tp)
 
        nsec = rtc_time() * sgi_clock_period
                        + sgi_clock_offset.tv_nsec;
-       tp->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &tp->tv_nsec)
-                       + sgi_clock_offset.tv_sec;
+       *tp = ns_to_timespec(nsec);
+       tp->tv_sec += sgi_clock_offset.tv_sec;
        return 0;
 };
 
@@ -481,11 +483,11 @@ static int sgi_clock_set(clockid_t clockid, struct timespec *tp)
 {
 
        u64 nsec;
-       u64 rem;
+       u32 rem;
 
        nsec = rtc_time() * sgi_clock_period;
 
-       sgi_clock_offset.tv_sec = tp->tv_sec - div_long_long_rem(nsec, NSEC_PER_SEC, &rem);
+       sgi_clock_offset.tv_sec = tp->tv_sec - div_u64_rem(nsec, NSEC_PER_SEC, &rem);
 
        if (rem <= tp->tv_nsec)
                sgi_clock_offset.tv_nsec = tp->tv_sec - rem;
@@ -644,9 +646,6 @@ static int sgi_timer_del(struct k_itimer *timr)
        return 0;
 }
 
-#define timespec_to_ns(x) ((x).tv_nsec + (x).tv_sec * NSEC_PER_SEC)
-#define ns_to_timespec(ts, nsec) (ts).tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &(ts).tv_nsec)
-
 /* Assumption: it_lock is already held with irq's disabled */
 static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
 {
@@ -659,9 +658,8 @@ static void sgi_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
                return;
        }
 
-       ns_to_timespec(cur_setting->it_interval, timr->it.mmtimer.incr * sgi_clock_period);
-       ns_to_timespec(cur_setting->it_value, (timr->it.mmtimer.expires - rtc_time())* sgi_clock_period);
-       return;
+       cur_setting->it_interval = ns_to_timespec(timr->it.mmtimer.incr * sgi_clock_period);
+       cur_setting->it_value = ns_to_timespec((timr->it.mmtimer.expires - rtc_time()) * sgi_clock_period);
 }
 
 
@@ -679,8 +677,8 @@ static int sgi_timer_set(struct k_itimer *timr, int flags,
                sgi_timer_get(timr, old_setting);
 
        sgi_timer_del(timr);
-       when = timespec_to_ns(new_setting->it_value);
-       period = timespec_to_ns(new_setting->it_interval);
+       when = timespec_to_ns(&new_setting->it_value);
+       period = timespec_to_ns(&new_setting->it_interval);
 
        if (when == 0)
                /* Clear timer */
@@ -695,7 +693,7 @@ static int sgi_timer_set(struct k_itimer *timr, int flags,
                unsigned long now;
 
                getnstimeofday(&n);
-               now = timespec_to_ns(n);
+               now = timespec_to_ns(&n);
                if (when > now)
                        when -= now;
                else
index 32fdbdd..9a2d644 100644 (file)
        __mod;                                                  \
 })
 
-/*
- * (long)X = ((long long)divs) / (long)div
- * (long)rem = ((long long)divs) % (long)div
- *
- * Warning, this will do an exception if X overflows.
- */
-#define div_long_long_rem(a, b, c) div_ll_X_l_rem(a, b, c)
-
-static inline long div_ll_X_l_rem(long long divs, long div, long *rem)
-{
-       long dum2;
-       asm("divl %2":"=a"(dum2), "=d"(*rem)
-           : "rm"(div), "A"(divs));
-
-       return dum2;
-
-}
-
 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder)
 {
        union {
diff --git a/include/linux/calc64.h b/include/linux/calc64.h
deleted file mode 100644 (file)
index ebf4b8f..0000000
+++ /dev/null
@@ -1,49 +0,0 @@
-#ifndef _LINUX_CALC64_H
-#define _LINUX_CALC64_H
-
-#include <linux/types.h>
-#include <asm/div64.h>
-
-/*
- * This is a generic macro which is used when the architecture
- * specific div64.h does not provide a optimized one.
- *
- * The 64bit dividend is divided by the divisor (data type long), the
- * result is returned and the remainder stored in the variable
- * referenced by remainder (data type long *). In contrast to the
- * do_div macro the dividend is kept intact.
- */
-#ifndef div_long_long_rem
-#define div_long_long_rem(dividend, divisor, remainder)        \
-       do_div_llr((dividend), divisor, remainder)
-
-static inline unsigned long do_div_llr(const long long dividend,
-                                      const long divisor, long *remainder)
-{
-       u64 result = dividend;
-
-       *(remainder) = do_div(result, divisor);
-       return (unsigned long) result;
-}
-#endif
-
-/*
- * Sign aware variation of the above. On some architectures a
- * negative dividend leads to an divide overflow exception, which
- * is avoided by the sign check.
- */
-static inline long div_long_long_rem_signed(const long long dividend,
-                                           const long divisor, long *remainder)
-{
-       long res;
-
-       if (unlikely(dividend < 0)) {
-               res = -div_long_long_rem(-dividend, divisor, remainder);
-               *remainder = -(*remainder);
-       } else
-               res = div_long_long_rem(dividend, divisor, remainder);
-
-       return res;
-}
-
-#endif
index 33ef710..abb6ac6 100644 (file)
@@ -1,7 +1,7 @@
 #ifndef _LINUX_JIFFIES_H
 #define _LINUX_JIFFIES_H
 
-#include <linux/calc64.h>
+#include <linux/math64.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/time.h>
index ae5c6c1..f1525ad 100644 (file)
@@ -4,8 +4,9 @@
 
 #include <linux/sched.h>
 #include <linux/posix-timers.h>
-#include <asm/uaccess.h>
 #include <linux/errno.h>
+#include <linux/math64.h>
+#include <asm/uaccess.h>
 
 static int check_clock(const clockid_t which_clock)
 {
@@ -47,12 +48,10 @@ static void sample_to_timespec(const clockid_t which_clock,
                               union cpu_time_count cpu,
                               struct timespec *tp)
 {
-       if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
-               tp->tv_sec = div_long_long_rem(cpu.sched,
-                                              NSEC_PER_SEC, &tp->tv_nsec);
-       } else {
+       if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
+               *tp = ns_to_timespec(cpu.sched);
+       else
                cputime_to_timespec(cpu.cpu, tp);
-       }
 }
 
 static inline int cpu_time_before(const clockid_t which_clock,
index 343e251..cbe0d5a 100644 (file)
@@ -392,13 +392,17 @@ EXPORT_SYMBOL(set_normalized_timespec);
 struct timespec ns_to_timespec(const s64 nsec)
 {
        struct timespec ts;
+       s32 rem;
 
        if (!nsec)
                return (struct timespec) {0, 0};
 
-       ts.tv_sec = div_long_long_rem_signed(nsec, NSEC_PER_SEC, &ts.tv_nsec);
-       if (unlikely(nsec < 0))
-               set_normalized_timespec(&ts, ts.tv_sec, ts.tv_nsec);
+       ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
+       if (unlikely(rem < 0)) {
+               ts.tv_sec--;
+               rem += NSEC_PER_SEC;
+       }
+       ts.tv_nsec = rem;
 
        return ts;
 }
@@ -528,8 +532,10 @@ jiffies_to_timespec(const unsigned long jiffies, struct timespec *value)
         * Convert jiffies to nanoseconds and separate with
         * one divide.
         */
-       u64 nsec = (u64)jiffies * TICK_NSEC;
-       value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &value->tv_nsec);
+       u32 rem;
+       value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
+                                   NSEC_PER_SEC, &rem);
+       value->tv_nsec = rem;
 }
 EXPORT_SYMBOL(jiffies_to_timespec);
 
@@ -567,12 +573,11 @@ void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
         * Convert jiffies to nanoseconds and separate with
         * one divide.
         */
-       u64 nsec = (u64)jiffies * TICK_NSEC;
-       long tv_usec;
+       u32 rem;
 
-       value->tv_sec = div_long_long_rem(nsec, NSEC_PER_SEC, &tv_usec);
-       tv_usec /= NSEC_PER_USEC;
-       value->tv_usec = tv_usec;
+       value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
+                                   NSEC_PER_SEC, &rem);
+       value->tv_usec = rem / NSEC_PER_USEC;
 }
 EXPORT_SYMBOL(jiffies_to_timeval);
 
index a4492f3..dbd6f89 100644 (file)
@@ -234,7 +234,7 @@ static inline void notify_cmos_timer(void) { }
  */
 int do_adjtimex(struct timex *txc)
 {
-       long mtemp, save_adjust, rem;
+       long mtemp, save_adjust;
        s64 freq_adj;
        int result;
 
@@ -345,9 +345,7 @@ int do_adjtimex(struct timex *txc)
                    freq_adj += time_freq;
                    freq_adj = min(freq_adj, (s64)MAXFREQ_NSEC);
                    time_freq = max(freq_adj, (s64)-MAXFREQ_NSEC);
-                   time_offset = div_long_long_rem_signed(time_offset,
-                                                          NTP_INTERVAL_FREQ,
-                                                          &rem);
+                   time_offset = div_s64(time_offset, NTP_INTERVAL_FREQ);
                    time_offset <<= SHIFT_UPDATE;
                } /* STA_PLL */
            } /* txc->modes & ADJ_OFFSET */
index 70db289..32b6262 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -22,6 +22,7 @@
 #include <linux/debugobjects.h>
 #include <linux/kallsyms.h>
 #include <linux/memory.h>
+#include <linux/math64.h>
 
 /*
  * Lock order:
@@ -3621,12 +3622,10 @@ static int list_locations(struct kmem_cache *s, char *buf,
                        len += sprintf(buf + len, "<not-available>");
 
                if (l->sum_time != l->min_time) {
-                       unsigned long remainder;
-
                        len += sprintf(buf + len, " age=%ld/%ld/%ld",
-                       l->min_time,
-                       div_long_long_rem(l->sum_time, l->count, &remainder),
-                       l->max_time);
+                               l->min_time,
+                               (long)div_u64(l->sum_time, l->count),
+                               l->max_time);
                } else
                        len += sprintf(buf + len, " age=%ld",
                                l->min_time);