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signals: Use hrtimer for sigtimedwait()

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We've converted most timeout related syscalls to hrtimers, but
sigtimedwait() did not get this treatment.

Convert it so we get a reasonable accuracy and remove the
user space exposure to the timer wheel properties.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: Cyril Hrubis <chrubis@suse.cz>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160704094341.787164909@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Thomas Gleixner 2016-07-04 09:50:25 +00:00 committed by Ingo Molnar
parent 177ec0a0a5
commit 2b1ecc3d1a
1 changed files with 10 additions and 14 deletions
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24
kernel/signal.c
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@ -2751,23 +2751,18 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
* @ts: upper bound on process time suspension
*/
int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
const struct timespec *ts)
const struct timespec *ts)
{
ktime_t *to = NULL, timeout = { .tv64 = KTIME_MAX };
struct task_struct *tsk = current;
long timeout = MAX_SCHEDULE_TIMEOUT;
sigset_t mask = *which;
int sig;
int sig, ret = 0;
if (ts) {
if (!timespec_valid(ts))
return -EINVAL;
timeout = timespec_to_jiffies(ts);
/*
* We can be close to the next tick, add another one
* to ensure we will wait at least the time asked for.
*/
if (ts->tv_sec || ts->tv_nsec)
timeout++;
timeout = timespec_to_ktime(*ts);
to = &timeout;
}
/*
@ -2778,7 +2773,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
spin_lock_irq(&tsk->sighand->siglock);
sig = dequeue_signal(tsk, &mask, info);
if (!sig && timeout) {
if (!sig && timeout.tv64) {
/*
* None ready, temporarily unblock those we're interested
* while we are sleeping in so that we'll be awakened when
@ -2790,8 +2785,9 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
recalc_sigpending();
spin_unlock_irq(&tsk->sighand->siglock);
timeout = freezable_schedule_timeout_interruptible(timeout);
__set_current_state(TASK_INTERRUPTIBLE);
ret = freezable_schedule_hrtimeout_range(to, tsk->timer_slack_ns,
HRTIMER_MODE_REL);
spin_lock_irq(&tsk->sighand->siglock);
__set_task_blocked(tsk, &tsk->real_blocked);
sigemptyset(&tsk->real_blocked);
@ -2801,7 +2797,7 @@ int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
if (sig)
return sig;
return timeout ? -EINTR : -EAGAIN;
return ret ? -EINTR : -EAGAIN;
}
/**