[RFC][PATCH 4/4] convert sys_nanosleep() to use set_timer_nsecs()

[Nishanth Aravamudan]

From: Nishanth Aravamudan <[EMAIL PROTECTED]>

Description: Add timespec and timeval conversion functions for
nanoseconds. Convert sys_nanosleep() to use schedule_timeout_nsecs().

Signed-off-by: Nishanth Aravamudan <[EMAIL PROTECTED]>

---

 include/linux/time.h |   33 +++++++++++++++++++++++++++++++++
 kernel/timer.c       |   24 ++++++++++++------------
 2 files changed, 45 insertions(+), 12 deletions(-)

diff -urpN 2.6.13-rc3-base/include/linux/time.h 
2.6.13-rc3-dev/include/linux/time.h
--- 2.6.13-rc3-base/include/linux/time.h        2005-07-14 12:46:46.000000000 
-0700
+++ 2.6.13-rc3-dev/include/linux/time.h 2005-07-14 12:48:25.000000000 -0700
@@ -2,6 +2,7 @@
 #define _LINUX_TIME_H
 
 #include <linux/types.h>
+#include <asm/div64.h>
 
 #ifdef __KERNEL__
 #include <linux/seqlock.h>
@@ -126,6 +127,38 @@ set_normalized_timespec (struct timespec
        ts->tv_nsec = nsec;
 }
 
+/* Inline helper functions */
+static inline struct timeval nsecs_to_timeval(u64 ns)
+{
+       struct timeval tv;
+       tv.tv_sec = div_long_long_rem(ns, NSEC_PER_SEC, &tv.tv_usec);
+       tv.tv_usec = (tv.tv_usec + NSEC_PER_USEC/2) / NSEC_PER_USEC;
+       return tv;
+}
+
+static inline struct timespec nsecs_to_timespec(u64 ns)
+{
+       struct timespec ts;
+       ts.tv_sec = div_long_long_rem(ns, NSEC_PER_SEC, &ts.tv_nsec);
+       return ts;
+}
+
+static inline u64 timespec_to_nsecs(struct timespec* ts)
+{
+       u64 ret;
+       ret = ((u64)ts->tv_sec) * NSEC_PER_SEC;
+       ret += (u64)ts->tv_nsec;
+       return ret;
+}
+
+static inline u64 timeval_to_nsecs(struct timeval* tv)
+{
+       u64 ret;
+       ret = ((u64)tv->tv_sec) * NSEC_PER_SEC;
+       ret += ((u64)tv->tv_usec) * NSEC_PER_USEC;
+       return ret;
+}
+
 #endif /* __KERNEL__ */
 
 #define NFDBITS                        __NFDBITS
diff -urpN 2.6.13-rc3-base/kernel/timer.c 2.6.13-rc3-dev/kernel/timer.c
--- 2.6.13-rc3-base/kernel/timer.c      2005-07-14 12:46:46.000000000 -0700
+++ 2.6.13-rc3-dev/kernel/timer.c       2005-07-14 12:48:25.000000000 -0700
@@ -1481,21 +1481,21 @@ asmlinkage long sys_gettid(void)
 
 static long __sched nanosleep_restart(struct restart_block *restart)
 {
-       unsigned long expire = restart->arg0, now = jiffies;
+       u64 expire = restart->arg0, now = do_monotonic_clock();
        struct timespec __user *rmtp = (struct timespec __user *) restart->arg1;
        long ret;
 
        /* Did it expire while we handled signals? */
-       if (!time_after(expire, now))
+       if (now > expire)
                return 0;
 
-       current->state = TASK_INTERRUPTIBLE;
-       expire = schedule_timeout(expire - now);
+       set_current_state(TASK_INTERRUPTIBLE);
+       expire = schedule_timeout_nsecs(expire - now);
 
        ret = 0;
        if (expire) {
                struct timespec t;
-               jiffies_to_timespec(expire, &t);
+               t = nsecs_to_timespec(expire);
 
                ret = -ERESTART_RESTARTBLOCK;
                if (rmtp && copy_to_user(rmtp, &t, sizeof(t)))
@@ -1508,7 +1508,7 @@ static long __sched nanosleep_restart(st
 asmlinkage long sys_nanosleep(struct timespec __user *rqtp, struct timespec 
__user *rmtp)
 {
        struct timespec t;
-       unsigned long expire;
+       u64 expire;
        long ret;
 
        if (copy_from_user(&t, rqtp, sizeof(t)))
@@ -1517,20 +1517,20 @@ asmlinkage long sys_nanosleep(struct tim
        if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0))
                return -EINVAL;
 
-       expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
-       current->state = TASK_INTERRUPTIBLE;
-       expire = schedule_timeout(expire);
+       expire = timespec_to_nsecs(&t);
+       set_current_state(TASK_INTERRUPTIBLE);
+       expire = schedule_timeout_nsecs(expire);
 
        ret = 0;
        if (expire) {
                struct restart_block *restart;
-               jiffies_to_timespec(expire, &t);
+               t = nsecs_to_timespec(expire);
                if (rmtp && copy_to_user(rmtp, &t, sizeof(t)))
                        return -EFAULT;
 
                restart = &current_thread_info()->restart_block;
                restart->fn = nanosleep_restart;
-               restart->arg0 = jiffies + expire;
+               restart->arg0 = do_monotonic_clock() + expire;
                restart->arg1 = (unsigned long) rmtp;
                ret = -ERESTART_RESTARTBLOCK;
        }
@@ -1642,7 +1642,7 @@ static void __devinit init_timers_cpu(in
        for (j = 0; j < TVR_SIZE; j++)
                INIT_LIST_HEAD(base->tv1.vec + j);
 
-       base->timer_jiffies = jiffies;
+       base->last_timer_time = 0UL;
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-
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