a2d4c71d15
It doesn't matter on normal return to userland path (we'll recheck the NOTIFY_RESUME flag anyway), but in case of exit_task_work() we'll need that as soon as we get callbacks capable of triggering more task_work_add(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
80 lines
1.7 KiB
C
80 lines
1.7 KiB
C
#include <linux/spinlock.h>
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#include <linux/task_work.h>
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#include <linux/tracehook.h>
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int
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task_work_add(struct task_struct *task, struct callback_head *twork, bool notify)
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{
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struct callback_head *last, *first;
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unsigned long flags;
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/*
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* Not inserting the new work if the task has already passed
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* exit_task_work() is the responisbility of callers.
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*/
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raw_spin_lock_irqsave(&task->pi_lock, flags);
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last = task->task_works;
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first = last ? last->next : twork;
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twork->next = first;
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if (last)
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last->next = twork;
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task->task_works = twork;
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raw_spin_unlock_irqrestore(&task->pi_lock, flags);
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/* test_and_set_bit() implies mb(), see tracehook_notify_resume(). */
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if (notify)
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set_notify_resume(task);
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return 0;
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}
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struct callback_head *
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task_work_cancel(struct task_struct *task, task_work_func_t func)
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{
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unsigned long flags;
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struct callback_head *last, *res = NULL;
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raw_spin_lock_irqsave(&task->pi_lock, flags);
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last = task->task_works;
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if (last) {
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struct callback_head *q = last, *p = q->next;
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while (1) {
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if (p->func == func) {
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q->next = p->next;
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if (p == last)
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task->task_works = q == p ? NULL : q;
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res = p;
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break;
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}
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if (p == last)
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break;
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q = p;
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p = q->next;
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}
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}
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raw_spin_unlock_irqrestore(&task->pi_lock, flags);
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return res;
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}
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void task_work_run(void)
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{
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struct task_struct *task = current;
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struct callback_head *p, *q;
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while (1) {
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raw_spin_lock_irq(&task->pi_lock);
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p = task->task_works;
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task->task_works = NULL;
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raw_spin_unlock_irq(&task->pi_lock);
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if (unlikely(!p))
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return;
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q = p->next; /* head */
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p->next = NULL; /* cut it */
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while (q) {
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p = q->next;
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q->func(q);
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q = p;
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}
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}
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}
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