From: Jens Axboe <[email protected]>
To: [email protected]
Cc: [email protected], [email protected],
[email protected], Jens Axboe <[email protected]>
Subject: [PATCH 5/9] kernel: abstract out task work helpers
Date: Thu, 20 Feb 2020 13:31:47 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
This is in preparation for adding a ditto sched_work list.
Signed-off-by: Jens Axboe <[email protected]>
---
kernel/task_work.c | 88 +++++++++++++++++++++++++++++-----------------
1 file changed, 56 insertions(+), 32 deletions(-)
diff --git a/kernel/task_work.c b/kernel/task_work.c
index 825f28259a19..3445421266e7 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -5,6 +5,22 @@
static struct callback_head work_exited; /* all we need is ->next == NULL */
+static int __task_work_add(struct task_struct *task,
+ struct callback_head **headptr,
+ struct callback_head *work)
+{
+ struct callback_head *head;
+
+ do {
+ head = READ_ONCE(*headptr);
+ if (unlikely(head == &work_exited))
+ return -ESRCH;
+ work->next = head;
+ } while (cmpxchg(headptr, head, work) != head);
+
+ return 0;
+}
+
/**
* task_work_add - ask the @task to execute @work->func()
* @task: the task which should run the callback
@@ -27,39 +43,25 @@ static struct callback_head work_exited; /* all we need is ->next == NULL */
int
task_work_add(struct task_struct *task, struct callback_head *work, bool notify)
{
- struct callback_head *head;
+ int ret;
- do {
- head = READ_ONCE(task->task_works);
- if (unlikely(head == &work_exited))
- return -ESRCH;
- work->next = head;
- } while (cmpxchg(&task->task_works, head, work) != head);
+ ret = __task_work_add(task, &task->task_works, work);
if (notify)
set_notify_resume(task);
- return 0;
+
+ return ret;
}
-/**
- * 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)
+static struct callback_head *__task_work_cancel(struct task_struct *task,
+ struct callback_head **headptr,
+ task_work_func_t func)
{
- struct callback_head **pprev = &task->task_works;
+ struct callback_head **pprev = headptr;
struct callback_head *work;
unsigned long flags;
- if (likely(!task->task_works))
+ if (likely(!(*headptr)))
return NULL;
/*
* If cmpxchg() fails we continue without updating pprev.
@@ -80,16 +82,25 @@ task_work_cancel(struct task_struct *task, task_work_func_t func)
}
/**
- * task_work_run - execute the works added by task_work_add()
+ * 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
*
- * 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.
+ * Find the last queued pending work with ->func == @func and remove
+ * it from queue.
+ *
+ * RETURNS:
+ * The found work or NULL if not found.
*/
-void task_work_run(void)
+struct callback_head *
+task_work_cancel(struct task_struct *task, task_work_func_t func)
+{
+ return __task_work_cancel(task, &task->task_works, func);
+}
+
+static void __task_work_run(struct task_struct *task,
+ struct callback_head **headptr)
{
- struct task_struct *task = current;
struct callback_head *work, *head, *next;
for (;;) {
@@ -99,14 +110,14 @@ void task_work_run(void)
*/
do {
head = NULL;
- work = READ_ONCE(task->task_works);
+ work = READ_ONCE(*headptr);
if (!work) {
if (task->flags & PF_EXITING)
head = &work_exited;
else
break;
}
- } while (cmpxchg(&task->task_works, work, head) != work);
+ } while (cmpxchg(headptr, work, head) != work);
if (!work)
break;
@@ -126,3 +137,16 @@ void task_work_run(void)
} while (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)
+{
+ __task_work_run(current, ¤t->task_works);
+}
--
2.25.1
next prev parent reply other threads:[~2020-02-20 20:32 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-20 20:31 [PATCHSET 0/9] io_uring: use polled async retry Jens Axboe
2020-02-20 20:31 ` [PATCH 1/9] io_uring: consider any io_read/write -EAGAIN as final Jens Axboe
2020-02-20 20:31 ` [PATCH 2/9] io_uring: io_accept() should hold on to submit reference on retry Jens Axboe
2020-02-20 20:31 ` [PATCH 3/9] sched: move io-wq/workqueue worker sched in/out into helpers Jens Axboe
2020-02-20 20:31 ` [PATCH 4/9] task_work_run: don't take ->pi_lock unconditionally Jens Axboe
2020-02-20 20:31 ` Jens Axboe [this message]
2020-02-20 21:07 ` [PATCH 5/9] kernel: abstract out task work helpers Peter Zijlstra
2020-02-20 21:08 ` Jens Axboe
2020-02-20 20:31 ` [PATCH 6/9] sched: add a sched_work list Jens Axboe
2020-02-20 21:17 ` Peter Zijlstra
2020-02-20 21:53 ` Jens Axboe
2020-02-20 22:02 ` Jens Axboe
2020-02-20 20:31 ` [PATCH 7/9] io_uring: add per-task callback handler Jens Axboe
2020-02-20 22:02 ` Jann Horn
2020-02-20 22:14 ` Jens Axboe
2020-02-20 22:18 ` Jens Axboe
2020-02-20 22:25 ` Jann Horn
2020-02-20 22:23 ` Jens Axboe
2020-02-20 22:38 ` Jann Horn
2020-02-20 22:56 ` Jens Axboe
2020-02-20 22:58 ` Jann Horn
2020-02-20 23:02 ` Jens Axboe
2020-02-20 22:23 ` Jann Horn
2020-02-20 23:00 ` Jens Axboe
2020-02-20 23:12 ` Jann Horn
2020-02-20 23:22 ` Jens Axboe
2020-02-21 1:29 ` Jann Horn
2020-02-21 17:32 ` Jens Axboe
2020-02-21 19:24 ` Jann Horn
2020-02-21 20:18 ` Jens Axboe
2020-02-20 22:56 ` Jann Horn
2020-02-21 10:47 ` Peter Zijlstra
2020-02-21 14:49 ` Jens Axboe
2020-02-21 15:02 ` Jann Horn
2020-02-21 16:12 ` Peter Zijlstra
2020-02-21 16:23 ` Peter Zijlstra
2020-02-21 20:13 ` Jens Axboe
2020-02-21 13:51 ` Pavel Begunkov
2020-02-21 14:50 ` Jens Axboe
2020-02-21 18:30 ` Pavel Begunkov
2020-02-21 19:10 ` Jens Axboe
2020-02-21 19:22 ` Pavel Begunkov
2020-02-23 6:00 ` Jens Axboe
2020-02-23 6:26 ` Jens Axboe
2020-02-23 11:02 ` Pavel Begunkov
2020-02-23 14:49 ` Jens Axboe
2020-02-23 14:58 ` Jens Axboe
2020-02-23 15:07 ` Jens Axboe
2020-02-23 18:04 ` Pavel Begunkov
2020-02-23 18:06 ` Jens Axboe
2020-02-23 17:55 ` Pavel Begunkov
2020-02-20 20:31 ` [PATCH 8/9] io_uring: mark requests that we can do poll async in io_op_defs Jens Axboe
2020-02-20 20:31 ` [PATCH 9/9] io_uring: use poll driven retry for files that support it Jens Axboe
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