[001/146] kthread: add the helper function kthread_run_on_cpu()

Commit Message

Andrew Morton Jan. 14, 2022, 10:02 p.m. UTC

From: Cai Huoqing <[e-mail]>
Subject: kthread: add the helper function kthread_run_on_cpu()

the helper function kthread_run_on_cpu() includes
kthread_create_on_cpu/wake_up_process().  In some cases, use
kthread_run_on_cpu() directly instead of
kthread_create_on_node/kthread_bind/wake_up_process() or
kthread_create_on_cpu/wake_up_process() or
kthreadd_create/kthread_bind/wake_up_process() to simplify the code.

[[e-mail]: export kthread_create_on_cpu to modules]
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Cai Huoqing <[e-mail]>
Cc: Bernard Metzler <[e-mail]>
Cc: Cai Huoqing <[e-mail]>
Cc: Daniel Bristot de Oliveira <[e-mail]>
Cc: Davidlohr Bueso <[e-mail]>
Cc: Doug Ledford <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jason Gunthorpe <[e-mail]>
Cc: Joel Fernandes (Google) <[e-mail]>
Cc: Josh Triplett <[e-mail]>
Cc: Lai Jiangshan <[e-mail]>
Cc: Mathieu Desnoyers <[e-mail]>
Cc: "Paul E . McKenney" <[e-mail]>
Cc: Steven Rostedt <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 include/linux/kthread.h |   25 +++++++++++++++++++++++++
 kernel/kthread.c        |    1 +
 2 files changed, 26 insertions(+)

Patch

--- a/include/linux/kthread.h~kthread-add-the-helper-function-kthread_run_on_cpu
+++ a/include/linux/kthread.h
@@ -56,6 +56,31 @@  bool kthread_is_per_cpu(struct task_stru
 	__k;								   \
 })
 
+/**
+ * kthread_run_on_cpu - create and wake a cpu bound thread.
+ * @threadfn: the function to run until signal_pending(current).
+ * @data: data ptr for @threadfn.
+ * @cpu: The cpu on which the thread should be bound,
+ * @namefmt: printf-style name for the thread. Format is restricted
+ *	     to "name.*%u". Code fills in cpu number.
+ *
+ * Description: Convenient wrapper for kthread_create_on_cpu()
+ * followed by wake_up_process().  Returns the kthread or
+ * ERR_PTR(-ENOMEM).
+ */
+static inline struct task_struct *
+kthread_run_on_cpu(int (*threadfn)(void *data), void *data,
+			unsigned int cpu, const char *namefmt)
+{
+	struct task_struct *p;
+
+	p = kthread_create_on_cpu(threadfn, data, cpu, namefmt);
+	if (!IS_ERR(p))
+		wake_up_process(p);
+
+	return p;
+}
+
 void free_kthread_struct(struct task_struct *k);
 void kthread_bind(struct task_struct *k, unsigned int cpu);
 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
--- a/kernel/kthread.c~kthread-add-the-helper-function-kthread_run_on_cpu
+++ a/kernel/kthread.c
@@ -523,6 +523,7 @@  struct task_struct *kthread_create_on_cp
 	to_kthread(p)->cpu = cpu;
 	return p;
 }
+EXPORT_SYMBOL(kthread_create_on_cpu);
 
 void kthread_set_per_cpu(struct task_struct *k, int cpu)
 {