X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fitimer.c;h=6a5fe93dd8bdd76a83732c18f27e5eb0f42de773;hb=483b4ee60edbefdfbff0dd538fb81f368d9e7c0d;hp=1dc988e0d2c77e962063c776b7b035800f51b9be;hpb=b7e4e85337060354f8b860cc38066725559313a4;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/itimer.c b/kernel/itimer.c index 1dc988e..6a5fe93 100644 --- a/kernel/itimer.c +++ b/kernel/itimer.c @@ -7,54 +7,63 @@ /* These are all the functions necessary to implement itimers */ #include -#include #include #include #include #include +#include #include -static unsigned long it_real_value(struct signal_struct *sig) +/** + * itimer_get_remtime - get remaining time for the timer + * + * @timer: the timer to read + * + * Returns the delta between the expiry time and now, which can be + * less than zero or 1usec for an pending expired timer + */ +static struct timeval itimer_get_remtime(struct hrtimer *timer) { - unsigned long val = 0; - if (timer_pending(&sig->real_timer)) { - val = sig->real_timer.expires - jiffies; + ktime_t rem = hrtimer_get_remaining(timer); - /* look out for negative/zero itimer.. */ - if ((long) val <= 0) - val = 1; - } - return val; + /* + * Racy but safe: if the itimer expires after the above + * hrtimer_get_remtime() call but before this condition + * then we return 0 - which is correct. + */ + if (hrtimer_active(timer)) { + if (rem.tv64 <= 0) + rem.tv64 = NSEC_PER_USEC; + } else + rem.tv64 = 0; + + return ktime_to_timeval(rem); } int do_getitimer(int which, struct itimerval *value) { struct task_struct *tsk = current; - unsigned long interval, val; cputime_t cinterval, cval; switch (which) { case ITIMER_REAL: spin_lock_irq(&tsk->sighand->siglock); - interval = tsk->signal->it_real_incr; - val = it_real_value(tsk->signal); + value->it_value = itimer_get_remtime(&tsk->signal->real_timer); + value->it_interval = + ktime_to_timeval(tsk->signal->it_real_incr); spin_unlock_irq(&tsk->sighand->siglock); - jiffies_to_timeval(val, &value->it_value); - jiffies_to_timeval(interval, &value->it_interval); break; case ITIMER_VIRTUAL: - read_lock(&tasklist_lock); spin_lock_irq(&tsk->sighand->siglock); cval = tsk->signal->it_virt_expires; cinterval = tsk->signal->it_virt_incr; if (!cputime_eq(cval, cputime_zero)) { - struct task_struct *t = tsk; - cputime_t utime = tsk->signal->utime; - do { - utime = cputime_add(utime, t->utime); - t = next_thread(t); - } while (t != tsk); + struct task_cputime cputime; + cputime_t utime; + + thread_group_cputime(tsk, &cputime); + utime = cputime.utime; if (cputime_le(cval, utime)) { /* about to fire */ cval = jiffies_to_cputime(1); } else { @@ -62,25 +71,19 @@ int do_getitimer(int which, struct itimerval *value) } } spin_unlock_irq(&tsk->sighand->siglock); - read_unlock(&tasklist_lock); cputime_to_timeval(cval, &value->it_value); cputime_to_timeval(cinterval, &value->it_interval); break; case ITIMER_PROF: - read_lock(&tasklist_lock); spin_lock_irq(&tsk->sighand->siglock); cval = tsk->signal->it_prof_expires; cinterval = tsk->signal->it_prof_incr; if (!cputime_eq(cval, cputime_zero)) { - struct task_struct *t = tsk; - cputime_t ptime = cputime_add(tsk->signal->utime, - tsk->signal->stime); - do { - ptime = cputime_add(ptime, - cputime_add(t->utime, - t->stime)); - t = next_thread(t); - } while (t != tsk); + struct task_cputime times; + cputime_t ptime; + + thread_group_cputime(tsk, ×); + ptime = cputime_add(times.utime, times.stime); if (cputime_le(cval, ptime)) { /* about to fire */ cval = jiffies_to_cputime(1); } else { @@ -88,7 +91,6 @@ int do_getitimer(int which, struct itimerval *value) } } spin_unlock_irq(&tsk->sighand->siglock); - read_unlock(&tasklist_lock); cputime_to_timeval(cval, &value->it_value); cputime_to_timeval(cinterval, &value->it_interval); break; @@ -98,7 +100,7 @@ int do_getitimer(int which, struct itimerval *value) return 0; } -asmlinkage long sys_getitimer(int which, struct itimerval __user *value) +SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value) { int error = -EFAULT; struct itimerval get_buffer; @@ -112,66 +114,68 @@ asmlinkage long sys_getitimer(int which, struct itimerval __user *value) return error; } + /* - * Called with P->sighand->siglock held and P->signal->real_timer inactive. - * If interval is nonzero, arm the timer for interval ticks from now. + * The timer is automagically restarted, when interval != 0 */ -static inline void it_real_arm(struct task_struct *p, unsigned long interval) +enum hrtimer_restart it_real_fn(struct hrtimer *timer) { - p->signal->it_real_value = interval; /* XXX unnecessary field?? */ - if (interval == 0) - return; - if (interval > (unsigned long) LONG_MAX) - interval = LONG_MAX; - /* the "+ 1" below makes sure that the timer doesn't go off before - * the interval requested. This could happen if - * time requested % (usecs per jiffy) is more than the usecs left - * in the current jiffy */ - p->signal->real_timer.expires = jiffies + interval + 1; - add_timer(&p->signal->real_timer); -} + struct signal_struct *sig = + container_of(timer, struct signal_struct, real_timer); -void it_real_fn(unsigned long __data) -{ - struct task_struct * p = (struct task_struct *) __data; + kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid); - send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p); - - /* - * Now restart the timer if necessary. We don't need any locking - * here because do_setitimer makes sure we have finished running - * before it touches anything. - */ - it_real_arm(p, p->signal->it_real_incr); + return HRTIMER_NORESTART; } +/* + * Returns true if the timeval is in canonical form + */ +#define timeval_valid(t) \ + (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC)) + int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) { struct task_struct *tsk = current; - unsigned long val, interval; + struct hrtimer *timer; + ktime_t expires; cputime_t cval, cinterval, nval, ninterval; + /* + * Validate the timevals in value. + */ + if (!timeval_valid(&value->it_value) || + !timeval_valid(&value->it_interval)) + return -EINVAL; + switch (which) { case ITIMER_REAL: +again: spin_lock_irq(&tsk->sighand->siglock); - interval = tsk->signal->it_real_incr; - val = it_real_value(tsk->signal); - if (val) - del_timer_sync(&tsk->signal->real_timer); - tsk->signal->it_real_incr = - timeval_to_jiffies(&value->it_interval); - it_real_arm(tsk, timeval_to_jiffies(&value->it_value)); - spin_unlock_irq(&tsk->sighand->siglock); + timer = &tsk->signal->real_timer; if (ovalue) { - jiffies_to_timeval(val, &ovalue->it_value); - jiffies_to_timeval(interval, - &ovalue->it_interval); + ovalue->it_value = itimer_get_remtime(timer); + ovalue->it_interval + = ktime_to_timeval(tsk->signal->it_real_incr); + } + /* We are sharing ->siglock with it_real_fn() */ + if (hrtimer_try_to_cancel(timer) < 0) { + spin_unlock_irq(&tsk->sighand->siglock); + goto again; } + expires = timeval_to_ktime(value->it_value); + if (expires.tv64 != 0) { + tsk->signal->it_real_incr = + timeval_to_ktime(value->it_interval); + hrtimer_start(timer, expires, HRTIMER_MODE_REL); + } else + tsk->signal->it_real_incr.tv64 = 0; + + spin_unlock_irq(&tsk->sighand->siglock); break; case ITIMER_VIRTUAL: nval = timeval_to_cputime(&value->it_value); ninterval = timeval_to_cputime(&value->it_interval); - read_lock(&tasklist_lock); spin_lock_irq(&tsk->sighand->siglock); cval = tsk->signal->it_virt_expires; cinterval = tsk->signal->it_virt_incr; @@ -186,7 +190,6 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) tsk->signal->it_virt_expires = nval; tsk->signal->it_virt_incr = ninterval; spin_unlock_irq(&tsk->sighand->siglock); - read_unlock(&tasklist_lock); if (ovalue) { cputime_to_timeval(cval, &ovalue->it_value); cputime_to_timeval(cinterval, &ovalue->it_interval); @@ -195,7 +198,6 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) case ITIMER_PROF: nval = timeval_to_cputime(&value->it_value); ninterval = timeval_to_cputime(&value->it_interval); - read_lock(&tasklist_lock); spin_lock_irq(&tsk->sighand->siglock); cval = tsk->signal->it_prof_expires; cinterval = tsk->signal->it_prof_incr; @@ -210,7 +212,6 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) tsk->signal->it_prof_expires = nval; tsk->signal->it_prof_incr = ninterval; spin_unlock_irq(&tsk->sighand->siglock); - read_unlock(&tasklist_lock); if (ovalue) { cputime_to_timeval(cval, &ovalue->it_value); cputime_to_timeval(cinterval, &ovalue->it_interval); @@ -222,9 +223,45 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) return 0; } -asmlinkage long sys_setitimer(int which, - struct itimerval __user *value, - struct itimerval __user *ovalue) +/** + * alarm_setitimer - set alarm in seconds + * + * @seconds: number of seconds until alarm + * 0 disables the alarm + * + * Returns the remaining time in seconds of a pending timer or 0 when + * the timer is not active. + * + * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid + * negative timeval settings which would cause immediate expiry. + */ +unsigned int alarm_setitimer(unsigned int seconds) +{ + struct itimerval it_new, it_old; + +#if BITS_PER_LONG < 64 + if (seconds > INT_MAX) + seconds = INT_MAX; +#endif + it_new.it_value.tv_sec = seconds; + it_new.it_value.tv_usec = 0; + it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; + + do_setitimer(ITIMER_REAL, &it_new, &it_old); + + /* + * We can't return 0 if we have an alarm pending ... And we'd + * better return too much than too little anyway + */ + if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) || + it_old.it_value.tv_usec >= 500000) + it_old.it_value.tv_sec++; + + return it_old.it_value.tv_sec; +} + +SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, + struct itimerval __user *, ovalue) { struct itimerval set_buffer, get_buffer; int error; @@ -240,6 +277,6 @@ asmlinkage long sys_setitimer(int which, return error; if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) - return -EFAULT; + return -EFAULT; return 0; }