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From:   Cai Huoqing <caihuoqing@baidu.com>
To:     <caihuoqing@baidu.com>
CC:     Bernard Metzler <bmt@zurich.ibm.com>,
        Doug Ledford <dledford@redhat.com>,
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        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
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        Ingo Molnar <mingo@redhat.com>,
        Daniel Bristot de Oliveira <bristot@kernel.org>,
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        <rcu@vger.kernel.org>
Subject: [PATCH 1/6] kthread: Add the helper macro kthread_run_on_cpu()
Date:   Thu, 21 Oct 2021 20:01:30 +0800
Message-ID: <20211021120135.3003-2-caihuoqing@baidu.com>
In-Reply-To: <20211021120135.3003-1-caihuoqing@baidu.com>
References: <20211021120135.3003-1-caihuoqing@baidu.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

the helper macro kthread_run_on_cpu() inculdes
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.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
---
 include/linux/kthread.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 346b0f269161..dfd125523aa9 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -56,6 +56,28 @@ bool kthread_is_per_cpu(struct task_struct *k);
 	__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_node()
+ * followed by wake_up_process().  Returns the kthread or
+ * ERR_PTR(-ENOMEM).
+ */
+#define kthread_run_on_cpu(threadfn, data, cpu, namefmt)		  \
+({									  \
+	struct task_struct *__k						  \
+		= kthread_create_on_cpu(threadfn, data, cpu_to_node(cpu), \
+					namefmt);			  \
+	if (!IS_ERR(__k))						  \
+		wake_up_process(__k);					  \
+	__k;								  \
+})
+
 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);
-- 
2.25.1