diff options
author | Oleg Nesterov <oleg@redhat.com> | 2013-09-11 14:23:31 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:58:27 -0700 |
commit | 892f6668f3a7088c7e30049c3d8e1844531602dc (patch) | |
tree | 68ad5c81f3bccaae821a891f1611135056829dc0 | |
parent | 205e550a0fb469ae73f91a903f27f4f63e774037 (diff) | |
download | linux-892f6668f3a7088c7e30049c3d8e1844531602dc.tar.bz2 |
task_work: documentation
No functional changes, just comments.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | kernel/task_work.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/kernel/task_work.c b/kernel/task_work.c index 6ee09856f725..8727032e3a6f 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -4,6 +4,23 @@ static struct callback_head work_exited; /* all we need is ->next == NULL */ +/** + * task_work_add - ask the @task to execute @work->func() + * @task: the task which should run the callback + * @work: the callback to run + * @notify: send the notification if true + * + * Queue @work for task_work_run() below and notify the @task if @notify. + * Fails if the @task is exiting/exited and thus it can't process this @work. + * Otherwise @work->func() will be called when the @task returns from kernel + * mode or exits. + * + * This is like the signal handler which runs in kernel mode, but it doesn't + * try to wake up the @task. + * + * RETURNS: + * 0 if succeeds or -ESRCH. + */ int task_work_add(struct task_struct *task, struct callback_head *work, bool notify) { @@ -21,6 +38,17 @@ task_work_add(struct task_struct *task, struct callback_head *work, bool notify) return 0; } +/** + * task_work_cancel - cancel a pending work added by task_work_add() + * @task: the task which should execute the work + * @func: identifies the work to remove + * + * Find the last queued pending work with ->func == @func and remove + * it from queue. + * + * RETURNS: + * The found work or NULL if not found. + */ struct callback_head * task_work_cancel(struct task_struct *task, task_work_func_t func) { @@ -46,6 +74,14 @@ task_work_cancel(struct task_struct *task, task_work_func_t func) return work; } +/** + * task_work_run - execute the works added by task_work_add() + * + * Flush the pending works. Should be used by the core kernel code. + * Called before the task returns to the user-mode or stops, or when + * it exits. In the latter case task_work_add() can no longer add the + * new work after task_work_run() returns. + */ void task_work_run(void) { struct task_struct *task = current; |