[for-next][PATCH 1/9] tracing: Replace deprecated CPU-hotplug functions.

From: Steven Rostedt
Date: Fri Aug 20 2021 - 10:12:04 EST


From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx

Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
kernel/trace/ring_buffer.c | 8 ++++----
kernel/trace/trace_hwlat.c | 28 ++++++++++++++--------------
kernel/trace/trace_osnoise.c | 16 ++++++++--------
3 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index e592d1df6f88..c5a3fbf19617 100644
--- a/kernel/trace/ring_buffer.c
+++ b/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:
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index 14f46aae1981..1b83d75eb103 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/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;
}
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index b61eefe5ccf5..65b08b8e5bf8 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/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)
--
2.30.2