1 // SPDX-License-Identifier: GPL-2.0
7 static struct callback_head work_exited; /* all we need is ->next == NULL */
19  * task_work_add - ask the @task to execute @work->func()
36  * user mode, or before entering guest mode.
41  * Otherwise @work->func() will be called when the @task goes through one of
52  * 0 if succeeds or -ESRCH.
61 			return -EINVAL;  in task_work_add()
63 			return -EINVAL;  in task_work_add()
68 	head = READ_ONCE(task->task_works);  in task_work_add()
71 			return -ESRCH;  in task_work_add()
72 		work->next = head;  in task_work_add()
73 	} while (!try_cmpxchg(&task->task_works, &head, work));  in task_work_add()
101  * task_work_cancel_match - cancel a pending work added by task_work_add()
114 	struct callback_head **pprev = &task->task_works;  in task_work_cancel_match()
126 	raw_spin_lock_irqsave(&task->pi_lock, flags);  in task_work_cancel_match()
130 			pprev = &work->next;  in task_work_cancel_match()
132 		} else if (try_cmpxchg(pprev, &work, work->next))  in task_work_cancel_match()
135 	raw_spin_unlock_irqrestore(&task->pi_lock, flags);  in task_work_cancel_match()
142 	return cb->func == data;  in task_work_func_match()
146  * task_work_cancel_func - cancel a pending work matching a function added by task_work_add()
150  * Find the last queued pending work with ->func == @func and remove
168  * task_work_cancel - cancel a pending work added by task_work_add()
187  * task_work_run - execute the works added by task_work_add()
190  * Called before the task returns to the user-mode or stops, or when
197 	struct callback_head *work, *head, *next;  in task_work_run()  local
201 		 * work->func() can do task_work_add(), do not set  in task_work_run()
204 		work = READ_ONCE(task->task_works);  in task_work_run()
208 				if (task->flags & PF_EXITING)  in task_work_run()
213 		} while (!try_cmpxchg(&task->task_works, &work, head));  in task_work_run()
220 		 * But it can remove another entry from the ->next list.  in task_work_run()
222 		raw_spin_lock_irq(&task->pi_lock);  in task_work_run()
223 		raw_spin_unlock_irq(&task->pi_lock);  in task_work_run()
226 			next = work->next;  in task_work_run()
227 			work->func(work);  in task_work_run()
228 			work = next;  in task_work_run()