[PATCH v6 02/20] kthread: Allow to call __kthread_create_on_node() with va_list args

Petr Mladek
2016-04-14T15:15:18Z

kthread_create_on_node() implements a bunch of logic to create
the kthread. It is already called by kthread_create_on_cpu().

We are going to extend the kthread worker API and will
need to call kthread_create_on_node() with va_list args there.

This patch does only a refactoring and does not modify the existing
behavior.

Signed-off-by: Petr Mladek <pmladek@suse.com>
---
kernel/kthread.c | 72 +++++++++++++++++++++++++++++++++-----------------------
1 file changed, 42 insertions(+), 30 deletions(-)

diff --git a/kernel/kthread.c b/kernel/kthread.c
index 1ffc11ec5546..bfe8742c4217 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -244,33 +244,10 @@ static void create_kthread(struct kthread_create_info *create)
}
}

-/**
- * kthread_create_on_node - create a kthread.
- * @threadfn: the function to run until signal_pending(current).
- * @data: data ptr for @threadfn.
- * @node: task and thread structures for the thread are allocated on this node
- * @namefmt: printf-style name for the thread.
- *
- * Description: This helper function creates and names a kernel
- * thread. The thread will be stopped: use wake_up_process() to start
- * it. See also kthread_run(). The new thread has SCHED_NORMAL policy and
- * is affine to all CPUs.
- *
- * If thread is going to be bound on a particular cpu, give its node
- * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE.
- * When woken, the thread will run @threadfn() with @data as its
- * argument. @threadfn() can either call do_exit() directly if it is a
- * standalone thread for which no one will call kthread_stop(), or
- * return when 'kthread_should_stop()' is true (which means
- * kthread_stop() has been called). The return value should be zero
- * or a negative error number; it will be passed to kthread_stop().
- *
- * Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR).
- */
-struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
- void *data, int node,
- const char namefmt[],
- ...)
+static struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
+ void *data, int node,
+ const char namefmt[],
+ va_list args)
{
DECLARE_COMPLETION_ONSTACK(done);
struct task_struct *task;
@@ -311,11 +288,8 @@ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
task = create->result;
if (!IS_ERR(task)) {
static const struct sched_param param = { .sched_priority = 0 };
- va_list args;

- va_start(args, namefmt);
vsnprintf(task->comm, sizeof(task->comm), namefmt, args);
- va_end(args);
/*
* root may have changed our (kthreadd's) priority or CPU mask.
* The kernel thread should not inherit these properties.
@@ -326,6 +300,44 @@ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
kfree(create);
return task;
}
+
+/**
+ * kthread_create_on_node - create a kthread.
+ * @threadfn: the function to run until signal_pending(current).
+ * @data: data ptr for @threadfn.
+ * @node: task and thread structures for the thread are allocated on this node
+ * @namefmt: printf-style name for the thread.
+ *
+ * Description: This helper function creates and names a kernel
+ * thread. The thread will be stopped: use wake_up_process() to start
+ * it. See also kthread_run(). The new thread has SCHED_NORMAL policy and
+ * is affine to all CPUs.
+ *
+ * If thread is going to be bound on a particular cpu, give its node
+ * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE.
+ * When woken, the thread will run @threadfn() with @data as its
+ * argument. @threadfn() can either call do_exit() directly if it is a
+ * standalone thread for which no one will call kthread_stop(), or
+ * return when 'kthread_should_stop()' is true (which means
+ * kthread_stop() has been called). The return value should be zero
+ * or a negative error number; it will be passed to kthread_stop().
+ *
+ * Returns a task_struct or ERR_PTR(-ENOMEM) or ERR_PTR(-EINTR).
+ */
+struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
+ void *data, int node,
+ const char namefmt[],
+ ...)
+{
+ struct task_struct *task;
+ va_list args;
+
+ va_start(args, namefmt);
+ task = __kthread_create_on_node(threadfn, data, node, namefmt, args);
+ va_end(args);
+
+ return task;
+}
EXPORT_SYMBOL(kthread_create_on_node);

static void __kthread_bind_mask(struct task_struct *p, const struct cpumask *mask, long state)
--
1.8.5.6