Hi Arnd,
 
> The code looks correct, but I think it would be nicer to change 
> hrtimer_nanosleep to take a kernel pointer and have all three
> callers (common_nsleep, sys_nanosleep and compat_sys_nanosleep)
> do the copy_to_user/put_compat_timespec in the caller.

Good idea, I had considered that but thought a larger cleanup might run
afoul of the merge rules :)

Regardless, here it is. Id appreciate a once over since it does affect
more code than the previous patch :)

Anton

--

Now we have high res timers on ppc64 I thought Id test them. It turns
out compat_sys_nanosleep hasnt been converted to the hrtimer code and so
is limited to HZ resolution.

The following patch pulls the copy_to_user out of hrtimer_nanosleep and
into the callers (common_nsleep, sys_nanosleep and compat_sys_nanosleep)
thus avoiding any set_fs(KERNEL_DS) or compat_alloc_userspace tricks.
 
Signed-off-by: Anton Blanchard <[EMAIL PROTECTED]>
---

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 540799b..7a9398e 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -300,7 +300,7 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t 
interval);
 
 /* Precise sleep: */
 extern long hrtimer_nanosleep(struct timespec *rqtp,
-                             struct timespec __user *rmtp,
+                             struct timespec *rmtp,
                              const enum hrtimer_mode mode,
                              const clockid_t clockid);
 extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
diff --git a/kernel/compat.c b/kernel/compat.c
index 3bae374..44abfce 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -40,62 +40,26 @@ int put_compat_timespec(const struct timespec *ts, struct 
compat_timespec __user
                        __put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
 }
 
-static long compat_nanosleep_restart(struct restart_block *restart)
-{
-       unsigned long expire = restart->arg0, now = jiffies;
-       struct compat_timespec __user *rmtp;
-
-       /* Did it expire while we handled signals? */
-       if (!time_after(expire, now))
-               return 0;
-
-       expire = schedule_timeout_interruptible(expire - now);
-       if (expire == 0)
-               return 0;
-
-       rmtp = (struct compat_timespec __user *)restart->arg1;
-       if (rmtp) {
-               struct compat_timespec ct;
-               struct timespec t;
-
-               jiffies_to_timespec(expire, &t);
-               ct.tv_sec = t.tv_sec;
-               ct.tv_nsec = t.tv_nsec;
-               if (copy_to_user(rmtp, &ct, sizeof(ct)))
-                       return -EFAULT;
-       }
-       /* The 'restart' block is already filled in */
-       return -ERESTART_RESTARTBLOCK;
-}
-
 asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
-               struct compat_timespec __user *rmtp)
+                                    struct compat_timespec __user *rmtp)
 {
-       struct timespec t;
-       struct restart_block *restart;
-       unsigned long expire;
+       struct timespec tu, rmt;
+       long ret;
 
-       if (get_compat_timespec(&t, rqtp))
+       if (get_compat_timespec(&tu, rqtp))
                return -EFAULT;
 
-       if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0))
+       if (!timespec_valid(&tu))
                return -EINVAL;
 
-       expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
-       expire = schedule_timeout_interruptible(expire);
-       if (expire == 0)
-               return 0;
+       ret = hrtimer_nanosleep(&tu, &rmt, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 
-       if (rmtp) {
-               jiffies_to_timespec(expire, &t);
-               if (put_compat_timespec(&t, rmtp))
+       if (ret) {
+               if (put_compat_timespec(&rmt, rmtp))
                        return -EFAULT;
        }
-       restart = &current_thread_info()->restart_block;
-       restart->fn = compat_nanosleep_restart;
-       restart->arg0 = jiffies + expire;
-       restart->arg1 = (unsigned long) rmtp;
-       return -ERESTART_RESTARTBLOCK;
+
+       return ret;
 }
 
 static inline long get_compat_itimerval(struct itimerval *o,
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index dc8a445..095e09e 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1286,8 +1286,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper 
*t, enum hrtimer_mode mod
 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 {
        struct hrtimer_sleeper t;
-       struct timespec __user *rmtp;
-       struct timespec tu;
+       struct timespec *rmtp;
        ktime_t time;
 
        restart->fn = do_no_restart_syscall;
@@ -1298,14 +1297,12 @@ long __sched hrtimer_nanosleep_restart(struct 
restart_block *restart)
        if (do_nanosleep(&t, HRTIMER_MODE_ABS))
                return 0;
 
-       rmtp = (struct timespec __user *) restart->arg1;
+       rmtp = (struct timespec *)restart->arg1;
        if (rmtp) {
                time = ktime_sub(t.timer.expires, t.timer.base->get_time());
                if (time.tv64 <= 0)
                        return 0;
-               tu = ktime_to_timespec(time);
-               if (copy_to_user(rmtp, &tu, sizeof(tu)))
-                       return -EFAULT;
+               *rmtp = ktime_to_timespec(time);
        }
 
        restart->fn = hrtimer_nanosleep_restart;
@@ -1314,12 +1311,11 @@ long __sched hrtimer_nanosleep_restart(struct 
restart_block *restart)
        return -ERESTART_RESTARTBLOCK;
 }
 
-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
                       const enum hrtimer_mode mode, const clockid_t clockid)
 {
        struct restart_block *restart;
        struct hrtimer_sleeper t;
-       struct timespec tu;
        ktime_t rem;
 
        hrtimer_init(&t.timer, clockid, mode);
@@ -1335,9 +1331,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct 
timespec __user *rmtp,
                rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
                if (rem.tv64 <= 0)
                        return 0;
-               tu = ktime_to_timespec(rem);
-               if (copy_to_user(rmtp, &tu, sizeof(tu)))
-                       return -EFAULT;
+               *rmtp = ktime_to_timespec(rem);
        }
 
        restart = &current_thread_info()->restart_block;
@@ -1353,7 +1347,8 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct 
timespec __user *rmtp,
 asmlinkage long
 sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 {
-       struct timespec tu;
+       struct timespec tu, rmt;
+       int ret;
 
        if (copy_from_user(&tu, rqtp, sizeof(tu)))
                return -EFAULT;
@@ -1361,7 +1356,14 @@ sys_nanosleep(struct timespec __user *rqtp, struct 
timespec __user *rmtp)
        if (!timespec_valid(&tu))
                return -EINVAL;
 
-       return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+       ret = hrtimer_nanosleep(&tu, &rmt, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+
+       if (ret) {
+               if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+                       return -EFAULT;
+       }
+
+       return ret;
 }
 
 /*
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 7a15afb..fc7dac2 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -980,9 +980,19 @@ sys_clock_getres(const clockid_t which_clock, struct 
timespec __user *tp)
 static int common_nsleep(const clockid_t which_clock, int flags,
                         struct timespec *tsave, struct timespec __user *rmtp)
 {
-       return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
+       struct timespec rmt;
+       int ret;
+
+       ret = hrtimer_nanosleep(tsave, &rmt, flags & TIMER_ABSTIME ?
                                 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
                                 which_clock);
+
+       if (ret) {
+               if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+                       return -EFAULT;
+       }
+
+       return ret;
 }
 
 asmlinkage long
-
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