diff options
Diffstat (limited to 'kernel/kthread.c')
| -rw-r--r-- | kernel/kthread.c | 53 |
1 files changed, 32 insertions, 21 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index 0fccf7d0c6a1..5b37a8567168 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -68,16 +68,6 @@ enum KTHREAD_BITS { KTHREAD_SHOULD_PARK, }; -static inline void set_kthread_struct(void *kthread) -{ - /* - * We abuse ->set_child_tid to avoid the new member and because it - * can't be wrongly copied by copy_process(). We also rely on fact - * that the caller can't exec, so PF_KTHREAD can't be cleared. - */ - current->set_child_tid = (__force void __user *)kthread; -} - static inline struct kthread *to_kthread(struct task_struct *k) { WARN_ON(!(k->flags & PF_KTHREAD)); @@ -103,6 +93,22 @@ static inline struct kthread *__to_kthread(struct task_struct *p) return kthread; } +void set_kthread_struct(struct task_struct *p) +{ + struct kthread *kthread; + + if (__to_kthread(p)) + return; + + kthread = kzalloc(sizeof(*kthread), GFP_KERNEL); + /* + * We abuse ->set_child_tid to avoid the new member and because it + * can't be wrongly copied by copy_process(). We also rely on fact + * that the caller can't exec, so PF_KTHREAD can't be cleared. + */ + p->set_child_tid = (__force void __user *)kthread; +} + void free_kthread_struct(struct task_struct *k) { struct kthread *kthread; @@ -272,8 +278,8 @@ static int kthread(void *_create) struct kthread *self; int ret; - self = kzalloc(sizeof(*self), GFP_KERNEL); - set_kthread_struct(self); + set_kthread_struct(current); + self = to_kthread(current); /* If user was SIGKILLed, I release the structure. */ done = xchg(&create->done, NULL); @@ -451,7 +457,7 @@ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data), } EXPORT_SYMBOL(kthread_create_on_node); -static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, long state) +static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, unsigned int state) { unsigned long flags; @@ -467,7 +473,7 @@ static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mas raw_spin_unlock_irqrestore(&p->pi_lock, flags); } -static void __kthread_bind(struct task_struct *p, unsigned int cpu, long state) +static void __kthread_bind(struct task_struct *p, unsigned int cpu, unsigned int state) { __kthread_bind_mask(p, cpumask_of(cpu), state); } @@ -1156,14 +1162,14 @@ static bool __kthread_cancel_work(struct kthread_work *work) * modify @dwork's timer so that it expires after @delay. If @delay is zero, * @work is guaranteed to be queued immediately. * - * Return: %true if @dwork was pending and its timer was modified, - * %false otherwise. + * Return: %false if @dwork was idle and queued, %true otherwise. * * A special case is when the work is being canceled in parallel. * It might be caused either by the real kthread_cancel_delayed_work_sync() * or yet another kthread_mod_delayed_work() call. We let the other command - * win and return %false here. The caller is supposed to synchronize these - * operations a reasonable way. + * win and return %true here. The return value can be used for reference + * counting and the number of queued works stays the same. Anyway, the caller + * is supposed to synchronize these operations a reasonable way. * * This function is safe to call from any context including IRQ handler. * See __kthread_cancel_work() and kthread_delayed_work_timer_fn() @@ -1175,13 +1181,15 @@ bool kthread_mod_delayed_work(struct kthread_worker *worker, { struct kthread_work *work = &dwork->work; unsigned long flags; - int ret = false; + int ret; raw_spin_lock_irqsave(&worker->lock, flags); /* Do not bother with canceling when never queued. */ - if (!work->worker) + if (!work->worker) { + ret = false; goto fast_queue; + } /* Work must not be used with >1 worker, see kthread_queue_work() */ WARN_ON_ONCE(work->worker != worker); @@ -1199,8 +1207,11 @@ bool kthread_mod_delayed_work(struct kthread_worker *worker, * be used for reference counting. */ kthread_cancel_delayed_work_timer(work, &flags); - if (work->canceling) + if (work->canceling) { + /* The number of works in the queue does not change. */ + ret = true; goto out; + } ret = __kthread_cancel_work(work); fast_queue: |