posix-cpu-timers: Remove unnecessary locking around cpu_clock_sample_group
As of e78c349679
("time, signal: Protect resource use statistics
with seqlock") cpu_clock_sample_group no longers needs siglock
protection. Unfortunately no one realized it at the time.
Remove the extra locking that is for cpu_clock_sample_group and not
for cpu_clock_sample. This significantly simplifies the code.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/878skmvdts.fsf@x220.int.ebiederm.org
This commit is contained in:
parent
a2efdbf4fc
commit
60f2ceaa81
|
@ -718,31 +718,10 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp
|
|||
/*
|
||||
* Sample the clock to take the difference with the expiry time.
|
||||
*/
|
||||
if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
|
||||
if (CPUCLOCK_PERTHREAD(timer->it_clock))
|
||||
now = cpu_clock_sample(clkid, p);
|
||||
} else {
|
||||
struct sighand_struct *sighand;
|
||||
unsigned long flags;
|
||||
|
||||
/*
|
||||
* Protect against sighand release/switch in exit/exec and
|
||||
* also make timer sampling safe if it ends up calling
|
||||
* thread_group_cputime().
|
||||
*/
|
||||
sighand = lock_task_sighand(p, &flags);
|
||||
if (unlikely(sighand == NULL)) {
|
||||
/*
|
||||
* The process has been reaped.
|
||||
* We can't even collect a sample any more.
|
||||
* Disarm the timer, nothing else to do.
|
||||
*/
|
||||
cpu_timer_setexpires(ctmr, 0);
|
||||
return;
|
||||
} else {
|
||||
now = cpu_clock_sample_group(clkid, p, false);
|
||||
unlock_task_sighand(p, &flags);
|
||||
}
|
||||
}
|
||||
else
|
||||
now = cpu_clock_sample_group(clkid, p, false);
|
||||
|
||||
if (now < expires) {
|
||||
itp->it_value = ns_to_timespec64(expires - now);
|
||||
|
@ -986,43 +965,22 @@ static void posix_cpu_timer_rearm(struct k_itimer *timer)
|
|||
/*
|
||||
* Fetch the current sample and update the timer's expiry time.
|
||||
*/
|
||||
if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
|
||||
if (CPUCLOCK_PERTHREAD(timer->it_clock))
|
||||
now = cpu_clock_sample(clkid, p);
|
||||
bump_cpu_timer(timer, now);
|
||||
if (unlikely(p->exit_state))
|
||||
return;
|
||||
|
||||
/* Protect timer list r/w in arm_timer() */
|
||||
sighand = lock_task_sighand(p, &flags);
|
||||
if (!sighand)
|
||||
return;
|
||||
} else {
|
||||
/*
|
||||
* Protect arm_timer() and timer sampling in case of call to
|
||||
* thread_group_cputime().
|
||||
*/
|
||||
sighand = lock_task_sighand(p, &flags);
|
||||
if (unlikely(sighand == NULL)) {
|
||||
/*
|
||||
* The process has been reaped.
|
||||
* We can't even collect a sample any more.
|
||||
*/
|
||||
cpu_timer_setexpires(ctmr, 0);
|
||||
return;
|
||||
} else if (unlikely(p->exit_state) && thread_group_empty(p)) {
|
||||
/* If the process is dying, no need to rearm */
|
||||
goto unlock;
|
||||
}
|
||||
else
|
||||
now = cpu_clock_sample_group(clkid, p, true);
|
||||
bump_cpu_timer(timer, now);
|
||||
/* Leave the sighand locked for the call below. */
|
||||
}
|
||||
|
||||
bump_cpu_timer(timer, now);
|
||||
|
||||
/* Protect timer list r/w in arm_timer() */
|
||||
sighand = lock_task_sighand(p, &flags);
|
||||
if (unlikely(sighand == NULL))
|
||||
return;
|
||||
|
||||
/*
|
||||
* Now re-arm for the new expiry time.
|
||||
*/
|
||||
arm_timer(timer);
|
||||
unlock:
|
||||
unlock_task_sighand(p, &flags);
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue