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| author | Oleg Nesterov <oleg@redhat.com> | 2016-11-29 20:51:03 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-12-08 16:36:19 +0300 |
| commit | efb29fbfa50c490dac64a9418ebe553be82df781 (patch) | |
| tree | 8b67af676011ff5aa7f4f3b008351952ece99fbb /kernel/kthread.c | |
| parent | eff9662547f358239b98dfc4a8e6905b494e14d6 (diff) | |
| download | linux-efb29fbfa50c490dac64a9418ebe553be82df781.tar.xz | |
kthread: Don't use to_live_kthread() in kthread_stop()
kthread_stop() had to use to_live_kthread() simply because it was not
possible to access kthread->exited after the exiting task clears
task_struct->vfork_done. Now that to_kthread() is always valid,
wake_up_process() + wait_for_completion() can be done
ununconditionally. It's not an issue anymore if the task has already issued
complete_vfork_done() or died.
The exiting task can get the spurious wakeup after mm_release() but this is
possible without this change too and is fine; do_task_dead() ensures that
this can't make any harm.
As a further enhancement this could be converted to task_work_add() later,
so ->vfork_done can be avoided completely.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Chunming Zhou <David1.Zhou@amd.com>
Cc: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20161129175103.GA5336@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/kthread.c')
| -rw-r--r-- | kernel/kthread.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index 7891a940007d..4dcbc8b5d6b6 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -532,13 +532,11 @@ int kthread_stop(struct task_struct *k) trace_sched_kthread_stop(k); get_task_struct(k); - kthread = to_live_kthread(k); - if (kthread) { - set_bit(KTHREAD_SHOULD_STOP, &kthread->flags); - __kthread_unpark(k, kthread); - wake_up_process(k); - wait_for_completion(&kthread->exited); - } + kthread = to_kthread(k); + set_bit(KTHREAD_SHOULD_STOP, &kthread->flags); + __kthread_unpark(k, kthread); + wake_up_process(k); + wait_for_completion(&kthread->exited); ret = k->exit_code; put_task_struct(k); |