return a;
}
+/*
+ * Divide and limit the result to res >= 1
+ *
+ * This is necessary to prevent signal delivery starvation, when the result of
+ * the division would be rounded down to 0.
+ */
+static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
+{
+ cputime_t res = cputime_div(time, div);
+
+ return max_t(cputime_t, res, 1);
+}
+
/*
* Update expiry time from increment, and increase overrun count,
* given the current clock sample.
BUG();
break;
case CPUCLOCK_PROF:
- left = cputime_div(cputime_sub(expires.cpu, val.cpu),
- nthreads);
+ left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+ nthreads);
do {
if (likely(!(t->flags & PF_EXITING))) {
ticks = cputime_add(prof_ticks(t), left);
} while (t != p);
break;
case CPUCLOCK_VIRT:
- left = cputime_div(cputime_sub(expires.cpu, val.cpu),
- nthreads);
+ left = cputime_div_non_zero(cputime_sub(expires.cpu, val.cpu),
+ nthreads);
do {
if (likely(!(t->flags & PF_EXITING))) {
ticks = cputime_add(virt_ticks(t), left);
case CPUCLOCK_SCHED:
nsleft = expires.sched - val.sched;
do_div(nsleft, nthreads);
+ nsleft = max_t(unsigned long long, nsleft, 1);
do {
if (likely(!(t->flags & PF_EXITING))) {
ns = t->sched_time + nsleft;
struct cpu_timer_list *next;
unsigned long i;
- if (CPUCLOCK_PERTHREAD(timer->it_clock) && (p->flags & PF_EXITING))
- return;
-
head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
p->cpu_timers : p->signal->cpu_timers);
head += CPUCLOCK_WHICH(timer->it_clock);
prof_left = cputime_sub(prof_expires, utime);
prof_left = cputime_sub(prof_left, stime);
- prof_left = cputime_div(prof_left, nthreads);
+ prof_left = cputime_div_non_zero(prof_left, nthreads);
virt_left = cputime_sub(virt_expires, utime);
- virt_left = cputime_div(virt_left, nthreads);
+ virt_left = cputime_div_non_zero(virt_left, nthreads);
if (sched_expires) {
sched_left = sched_expires - sched_time;
do_div(sched_left, nthreads);
+ sched_left = max_t(unsigned long long, sched_left, 1);
} else {
sched_left = 0;
}
t = tsk;
do {
+ if (unlikely(t->flags & PF_EXITING))
+ continue;
+
ticks = cputime_add(cputime_add(t->utime, t->stime),
prof_left);
if (!cputime_eq(prof_expires, cputime_zero) &&
t->it_sched_expires > sched)) {
t->it_sched_expires = sched;
}
-
- do {
- t = next_thread(t);
- } while (unlikely(t->flags & PF_EXITING));
- } while (t != tsk);
+ } while ((t = next_thread(t)) != tsk);
}
}
#undef UNEXPIRED
- BUG_ON(tsk->exit_state);
-
/*
* Double-check with locks held.
*/
read_lock(&tasklist_lock);
- spin_lock(&tsk->sighand->siglock);
+ if (likely(tsk->signal != NULL)) {
+ spin_lock(&tsk->sighand->siglock);
- /*
- * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
- * all the timers that are firing, and put them on the firing list.
- */
- check_thread_timers(tsk, &firing);
- check_process_timers(tsk, &firing);
+ /*
+ * Here we take off tsk->cpu_timers[N] and tsk->signal->cpu_timers[N]
+ * all the timers that are firing, and put them on the firing list.
+ */
+ check_thread_timers(tsk, &firing);
+ check_process_timers(tsk, &firing);
- /*
- * We must release these locks before taking any timer's lock.
- * There is a potential race with timer deletion here, as the
- * siglock now protects our private firing list. We have set
- * the firing flag in each timer, so that a deletion attempt
- * that gets the timer lock before we do will give it up and
- * spin until we've taken care of that timer below.
- */
- spin_unlock(&tsk->sighand->siglock);
+ /*
+ * We must release these locks before taking any timer's lock.
+ * There is a potential race with timer deletion here, as the
+ * siglock now protects our private firing list. We have set
+ * the firing flag in each timer, so that a deletion attempt
+ * that gets the timer lock before we do will give it up and
+ * spin until we've taken care of that timer below.
+ */
+ spin_unlock(&tsk->sighand->siglock);
+ }
read_unlock(&tasklist_lock);
/*
}
}
-static long posix_cpu_clock_nanosleep_restart(struct restart_block *);
-
-int posix_cpu_nsleep(const clockid_t which_clock, int flags,
- struct timespec *rqtp)
+static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
+ struct timespec *rqtp, struct itimerspec *it)
{
- struct restart_block *restart_block =
- ¤t_thread_info()->restart_block;
struct k_itimer timer;
int error;
- /*
- * Diagnose required errors first.
- */
- if (CPUCLOCK_PERTHREAD(which_clock) &&
- (CPUCLOCK_PID(which_clock) == 0 ||
- CPUCLOCK_PID(which_clock) == current->pid))
- return -EINVAL;
-
/*
* Set up a temporary timer and then wait for it to go off.
*/
error = posix_cpu_timer_create(&timer);
timer.it_process = current;
if (!error) {
- struct timespec __user *rmtp;
static struct itimerspec zero_it;
- struct itimerspec it = { .it_value = *rqtp,
- .it_interval = {} };
+
+ memset(it, 0, sizeof *it);
+ it->it_value = *rqtp;
spin_lock_irq(&timer.it_lock);
- error = posix_cpu_timer_set(&timer, flags, &it, NULL);
+ error = posix_cpu_timer_set(&timer, flags, it, NULL);
if (error) {
spin_unlock_irq(&timer.it_lock);
return error;
* We were interrupted by a signal.
*/
sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
- posix_cpu_timer_set(&timer, 0, &zero_it, &it);
+ posix_cpu_timer_set(&timer, 0, &zero_it, it);
spin_unlock_irq(&timer.it_lock);
- if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
+ if ((it->it_value.tv_sec | it->it_value.tv_nsec) == 0) {
/*
* It actually did fire already.
*/
return 0;
}
+ error = -ERESTART_RESTARTBLOCK;
+ }
+
+ return error;
+}
+
+int posix_cpu_nsleep(const clockid_t which_clock, int flags,
+ struct timespec *rqtp, struct timespec __user *rmtp)
+{
+ struct restart_block *restart_block =
+ ¤t_thread_info()->restart_block;
+ struct itimerspec it;
+ int error;
+
+ /*
+ * Diagnose required errors first.
+ */
+ if (CPUCLOCK_PERTHREAD(which_clock) &&
+ (CPUCLOCK_PID(which_clock) == 0 ||
+ CPUCLOCK_PID(which_clock) == current->pid))
+ return -EINVAL;
+
+ error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
+
+ if (error == -ERESTART_RESTARTBLOCK) {
+
+ if (flags & TIMER_ABSTIME)
+ return -ERESTARTNOHAND;
/*
- * Report back to the user the time still remaining.
- */
- rmtp = (struct timespec __user *) restart_block->arg1;
- if (rmtp != NULL && !(flags & TIMER_ABSTIME) &&
- copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+ * Report back to the user the time still remaining.
+ */
+ if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
return -EFAULT;
- restart_block->fn = posix_cpu_clock_nanosleep_restart;
- /* Caller already set restart_block->arg1 */
+ restart_block->fn = posix_cpu_nsleep_restart;
restart_block->arg0 = which_clock;
+ restart_block->arg1 = (unsigned long) rmtp;
restart_block->arg2 = rqtp->tv_sec;
restart_block->arg3 = rqtp->tv_nsec;
-
- error = -ERESTART_RESTARTBLOCK;
}
-
return error;
}
-static long
-posix_cpu_clock_nanosleep_restart(struct restart_block *restart_block)
+long posix_cpu_nsleep_restart(struct restart_block *restart_block)
{
clockid_t which_clock = restart_block->arg0;
- struct timespec t = { .tv_sec = restart_block->arg2,
- .tv_nsec = restart_block->arg3 };
+ struct timespec __user *rmtp;
+ struct timespec t;
+ struct itimerspec it;
+ int error;
+
+ rmtp = (struct timespec __user *) restart_block->arg1;
+ t.tv_sec = restart_block->arg2;
+ t.tv_nsec = restart_block->arg3;
+
restart_block->fn = do_no_restart_syscall;
- return posix_cpu_nsleep(which_clock, TIMER_ABSTIME, &t);
+ error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
+
+ if (error == -ERESTART_RESTARTBLOCK) {
+ /*
+ * Report back to the user the time still remaining.
+ */
+ if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+ return -EFAULT;
+
+ restart_block->fn = posix_cpu_nsleep_restart;
+ restart_block->arg0 = which_clock;
+ restart_block->arg1 = (unsigned long) rmtp;
+ restart_block->arg2 = t.tv_sec;
+ restart_block->arg3 = t.tv_nsec;
+ }
+ return error;
+
}
return posix_cpu_timer_create(timer);
}
static int process_cpu_nsleep(const clockid_t which_clock, int flags,
- struct timespec *rqtp)
+ struct timespec *rqtp,
+ struct timespec __user *rmtp)
{
- return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
+ return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
+}
+static long process_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+ return -EINVAL;
}
static int thread_cpu_clock_getres(const clockid_t which_clock,
struct timespec *tp)
return posix_cpu_timer_create(timer);
}
static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
- struct timespec *rqtp)
+ struct timespec *rqtp, struct timespec __user *rmtp)
+{
+ return -EINVAL;
+}
+static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
{
return -EINVAL;
}
.clock_set = do_posix_clock_nosettime,
.timer_create = process_cpu_timer_create,
.nsleep = process_cpu_nsleep,
+ .nsleep_restart = process_cpu_nsleep_restart,
};
struct k_clock thread = {
.clock_getres = thread_cpu_clock_getres,
.clock_set = do_posix_clock_nosettime,
.timer_create = thread_cpu_timer_create,
.nsleep = thread_cpu_nsleep,
+ .nsleep_restart = thread_cpu_nsleep_restart,
};
register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
git.openpandora.org / pandora-kernel.git / blobdiff