Merge tag 'trace-v6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

- Fix setting affinity of hwlat threads in containers

Using sched_set_affinity() has unwanted side effects when being
called within a container. Use set_cpus_allowed_ptr() instead

- Fix per cpu thread management of the hwlat tracer:
- Do not start per_cpu threads if one is already running for the CPU
- When starting per_cpu threads, do not clear the kthread variable
as it may already be set to running per cpu threads

- Fix return value for test_gen_kprobe_cmd()

On error the return value was overwritten by being set to the result
of the call from kprobe_event_delete(), which would likely succeed,
and thus have the function return success

- Fix splice() reads from the trace file that was broken by commit
36e2c7421f02 ("fs: don't allow splice read/write without explicit
ops")

- Remove obsolete and confusing comment in ring_buffer.c

The original design of the ring buffer used struct page flags for
tricks to optimize, which was shortly removed due to them being
tricks. But a comment for those tricks remained

- Set local functions and variables to static

* tag 'trace-v6.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr
ring-buffer: remove obsolete comment for free_buffer_page()
tracing: Make splice_read available again
ftrace: Set direct_ops storage-class-specifier to static
trace/hwlat: Do not start per-cpu thread if it is already running
trace/hwlat: Do not wipe the contents of per-cpu thread data
tracing/osnoise: set several trace_osnoise.c variables storage-class-specifier to static
tracing: Fix wrong return in kprobe_event_gen_test.c

kernel/trace/ftrace.c

···
 	arch_ftrace_set_direct_caller(fregs, addr);
 }
 
-struct ftrace_ops direct_ops = {
+static struct ftrace_ops direct_ops = {
 	.func		= call_direct_funcs,
 	.flags		= FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
 			  | FTRACE_OPS_FL_PERMANENT,

kernel/trace/kprobe_event_gen_test.c

···
 	if (trace_event_file_is_valid(gen_kprobe_test))
 		gen_kprobe_test = NULL;
 	/* We got an error after creating the event, delete it */
-	ret = kprobe_event_delete("gen_kprobe_test");
+	kprobe_event_delete("gen_kprobe_test");
 	goto out;
 }
 
···
 	if (trace_event_file_is_valid(gen_kretprobe_test))
 		gen_kretprobe_test = NULL;
 	/* We got an error after creating the event, delete it */
-	ret = kprobe_event_delete("gen_kretprobe_test");
+	kprobe_event_delete("gen_kretprobe_test");
 	goto out;
 }
 

kernel/trace/ring_buffer.c

···
 	local_set(&bpage->commit, 0);
 }
 
-/*
- * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
- * this issue out.
- */
 static void free_buffer_page(struct buffer_page *bpage)
 {
 	free_page((unsigned long)bpage->page);

kernel/trace/trace.c

···
 static const struct file_operations tracing_fops = {
 	.open		= tracing_open,
 	.read		= seq_read,
+	.read_iter	= seq_read_iter,
+	.splice_read	= generic_file_splice_read,
 	.write		= tracing_write_stub,
 	.llseek		= tracing_lseek,
 	.release	= tracing_release,

kernel/trace/trace_hwlat.c

···
 	cpumask_clear(current_mask);
 	cpumask_set_cpu(next_cpu, current_mask);
 
-	sched_setaffinity(0, current_mask);
+	set_cpus_allowed_ptr(current, current_mask);
 	return;
 
  change_mode:
···
 
 	}
 
-	sched_setaffinity(kthread->pid, current_mask);
+	set_cpus_allowed_ptr(kthread, current_mask);
 
 	kdata->kthread = kthread;
 	wake_up_process(kthread);
···
 static int start_cpu_kthread(unsigned int cpu)
 {
 	struct task_struct *kthread;
+
+	/* Do not start a new hwlatd thread if it is already running */
+	if (per_cpu(hwlat_per_cpu_data, cpu).kthread)
+		return 0;
 
 	kthread = kthread_run_on_cpu(kthread_fn, NULL, cpu, "hwlatd/%u");
 	if (IS_ERR(kthread)) {
···
 	 * Run only on CPUs in which hwlat is allowed to run.
 	 */
 	cpumask_and(current_mask, cpu_online_mask, tr->tracing_cpumask);
-
-	for_each_online_cpu(cpu)
-		per_cpu(hwlat_per_cpu_data, cpu).kthread = NULL;
 
 	for_each_cpu(cpu, current_mask) {
 		retval = start_cpu_kthread(cpu);

kernel/trace/trace_osnoise.c

···
 /*
  * Per-cpu runtime information.
  */
-DEFINE_PER_CPU(struct osnoise_variables, per_cpu_osnoise_var);
+static DEFINE_PER_CPU(struct osnoise_variables, per_cpu_osnoise_var);
 
 /*
  * this_cpu_osn_var - Return the per-cpu osnoise_variables on its relative CPU
···
 	u64			count;
 };
 
-DEFINE_PER_CPU(struct timerlat_variables, per_cpu_timerlat_var);
+static DEFINE_PER_CPU(struct timerlat_variables, per_cpu_timerlat_var);
 
 /*
  * this_cpu_tmr_var - Return the per-cpu timerlat_variables on its relative CPU
···
 /*
  * Protect the interface.
  */
-struct mutex interface_lock;
+static struct mutex interface_lock;
 
 /*
  * Tracer data.
···
 /*
  * osnoise/timerlat_period: min 100 us, max 1 s
  */
-u64 timerlat_min_period = 100;
-u64 timerlat_max_period = 1000000;
+static u64 timerlat_min_period = 100;
+static u64 timerlat_max_period = 1000000;
 static struct trace_min_max_param timerlat_period = {
 	.lock	= &interface_lock,
 	.val	= &osnoise_data.timerlat_period,