trace/hwlat: make use of the helper function kthread_run_on_cpu()

[ Upstream commit ff78f6679d2e223e073fcbdc8f70b6bc0abadf99 ]

Replace kthread_create_on_cpu/wake_up_process() with kthread_run_on_cpu()
to simplify the code.

Link: https://lkml.kernel.org/r/20211022025711.3673-7-caihuoqing@baidu.com
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Cc: Bernard Metzler <bmt@zurich.ibm.com>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stable-dep-of: 08697bca9bbb ("trace/hwlat: Do not start per-cpu thread if it is already running")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 455f5edf008b85c897d808d4bf5b60ac2d491e50..72eeab938f1de3fe63644a6fbb126a1be35e247c 100644 (file)
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -491,18 +491,14 @@ static void stop_per_cpu_kthreads(void)
 static int start_cpu_kthread(unsigned int cpu)
 {
        struct task_struct *kthread;
-       char comm[24];
 
-       snprintf(comm, 24, "hwlatd/%d", cpu);
-
-       kthread = kthread_create_on_cpu(kthread_fn, NULL, cpu, comm);
+       kthread = kthread_run_on_cpu(kthread_fn, NULL, cpu, "hwlatd/%u");
        if (IS_ERR(kthread)) {
                pr_err(BANNER "could not start sampling thread\n");
                return -ENOMEM;
        }
 
        per_cpu(hwlat_per_cpu_data, cpu).kthread = kthread;
-       wake_up_process(kthread);
 
        return 0;
 }