tracing: Replace deprecated CPU-hotplug functions.

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Link: https://lkml.kernel.org/r/20210803141621.780504-37-bigeasy@linutronix.de

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/ring_buffer.c

@@ -2111,7 +2111,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 			}
 		}
 
-		get_online_cpus();
+		cpus_read_lock();
 		/*
 		 * Fire off all the required work handlers
 		 * We can't schedule on offline CPUs, but it's not necessary
@@ -2143,7 +2143,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 			cpu_buffer->nr_pages_to_update = 0;
 		}
 
-		put_online_cpus();
+		cpus_read_unlock();
 	} else {
 		cpu_buffer = buffer->buffers[cpu_id];
 
@@ -2171,7 +2171,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 			goto out_err;
 		}
 
-		get_online_cpus();
+		cpus_read_lock();
 
 		/* Can't run something on an offline CPU. */
 		if (!cpu_online(cpu_id))
@@ -2183,7 +2183,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 		}
 
 		cpu_buffer->nr_pages_to_update = 0;
-		put_online_cpus();
+		cpus_read_unlock();
 	}
 
  out:

kernel/trace/trace_hwlat.c

@@ -325,10 +325,10 @@ static void move_to_next_cpu(void)
 	if (!cpumask_equal(current_mask, current->cpus_ptr))
 		goto change_mode;
 
-	get_online_cpus();
+	cpus_read_lock();
 	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
 	next_cpu = cpumask_next(raw_smp_processor_id(), current_mask);
-	put_online_cpus();
+	cpus_read_unlock();
 
 	if (next_cpu >= nr_cpu_ids)
 		next_cpu = cpumask_first(current_mask);
@@ -398,7 +398,7 @@ static void stop_single_kthread(void)
 	struct hwlat_kthread_data *kdata = get_cpu_data();
 	struct task_struct *kthread;
 
-	get_online_cpus();
+	cpus_read_lock();
 	kthread = kdata->kthread;
 
 	if (!kthread)
@@ -408,7 +408,7 @@ static void stop_single_kthread(void)
 	kdata->kthread = NULL;
 
 out_put_cpus:
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 
@@ -425,14 +425,14 @@ static int start_single_kthread(struct trace_array *tr)
 	struct task_struct *kthread;
 	int next_cpu;
 
-	get_online_cpus();
+	cpus_read_lock();
 	if (kdata->kthread)
 		goto out_put_cpus;
 
 	kthread = kthread_create(kthread_fn, NULL, "hwlatd");
 	if (IS_ERR(kthread)) {
 		pr_err(BANNER "could not start sampling thread\n");
-		put_online_cpus();
+		cpus_read_unlock();
 		return -ENOMEM;
 	}
 
@@ -452,7 +452,7 @@ static int start_single_kthread(struct trace_array *tr)
 	wake_up_process(kthread);
 
 out_put_cpus:
-	put_online_cpus();
+	cpus_read_unlock();
 	return 0;
 }
 
@@ -479,10 +479,10 @@ static void stop_per_cpu_kthreads(void)
 {
 	unsigned int cpu;
 
-	get_online_cpus();
+	cpus_read_lock();
 	for_each_online_cpu(cpu)
 		stop_cpu_kthread(cpu);
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 /*
@@ -515,7 +515,7 @@ static void hwlat_hotplug_workfn(struct work_struct *dummy)
 
 	mutex_lock(&trace_types_lock);
 	mutex_lock(&hwlat_data.lock);
-	get_online_cpus();
+	cpus_read_lock();
 
 	if (!hwlat_busy || hwlat_data.thread_mode != MODE_PER_CPU)
 		goto out_unlock;
@@ -526,7 +526,7 @@ static void hwlat_hotplug_workfn(struct work_struct *dummy)
 	start_cpu_kthread(cpu);
 
 out_unlock:
-	put_online_cpus();
+	cpus_read_unlock();
 	mutex_unlock(&hwlat_data.lock);
 	mutex_unlock(&trace_types_lock);
 }
@@ -582,7 +582,7 @@ static int start_per_cpu_kthreads(struct trace_array *tr)
 	unsigned int cpu;
 	int retval;
 
-	get_online_cpus();
+	cpus_read_lock();
 	/*
 	 * Run only on CPUs in which hwlat is allowed to run.
 	 */
@@ -596,12 +596,12 @@ static int start_per_cpu_kthreads(struct trace_array *tr)
 		if (retval)
 			goto out_error;
 	}
-	put_online_cpus();
+	cpus_read_unlock();
 
 	return 0;
 
 out_error:
-	put_online_cpus();
+	cpus_read_unlock();
 	stop_per_cpu_kthreads();
 	return retval;
 }

kernel/trace/trace_osnoise.c

@@ -1498,12 +1498,12 @@ static void stop_per_cpu_kthreads(void)
 {
 	int cpu;
 
-	get_online_cpus();
+	cpus_read_lock();
 
 	for_each_online_cpu(cpu)
 		stop_kthread(cpu);
 
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 /*
@@ -1551,7 +1551,7 @@ static int start_per_cpu_kthreads(struct trace_array *tr)
 	int retval;
 	int cpu;
 
-	get_online_cpus();
+	cpus_read_lock();
 	/*
 	 * Run only on CPUs in which trace and osnoise are allowed to run.
 	 */
@@ -1572,7 +1572,7 @@ static int start_per_cpu_kthreads(struct trace_array *tr)
 		}
 	}
 
-	put_online_cpus();
+	cpus_read_unlock();
 
 	return 0;
 }
@@ -1590,7 +1590,7 @@ static void osnoise_hotplug_workfn(struct work_struct *dummy)
 		goto out_unlock_trace;
 
 	mutex_lock(&interface_lock);
-	get_online_cpus();
+	cpus_read_lock();
 
 	if (!cpumask_test_cpu(cpu, &osnoise_cpumask))
 		goto out_unlock;
@@ -1601,7 +1601,7 @@ static void osnoise_hotplug_workfn(struct work_struct *dummy)
 	start_kthread(cpu);
 
 out_unlock:
-	put_online_cpus();
+	cpus_read_unlock();
 	mutex_unlock(&interface_lock);
 out_unlock_trace:
 	mutex_unlock(&trace_types_lock);
@@ -1743,11 +1743,11 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
 	/*
 	 * osnoise_cpumask is read by CPU hotplug operations.
 	 */
-	get_online_cpus();
+	cpus_read_lock();
 
 	cpumask_copy(&osnoise_cpumask, osnoise_cpumask_new);
 
-	put_online_cpus();
+	cpus_read_unlock();
 	mutex_unlock(&interface_lock);
 
 	if (running)