ftrace: Use this_cpu_ptr() instead of per_cpu_ptr(smp_processor_id())

Use this_cpu_ptr() instead of open coding the equivalent in various
ftrace functions.

Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/87y14t6ofi.wl-me@linux.beauty
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

kernel/trace/trace_functions.c

@@ -184,7 +184,6 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
 	struct trace_array_cpu *data;
 	unsigned int trace_ctx;
 	int bit;
-	int cpu;
 
 	if (unlikely(!tr->function_enabled))
 		return;
@@ -195,8 +194,7 @@ function_trace_call(unsigned long ip, unsigned long parent_ip,
 
 	trace_ctx = tracing_gen_ctx();
 
-	cpu = smp_processor_id();
-	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	data = this_cpu_ptr(tr->array_buffer.data);
 	if (!atomic_read(&data->disabled))
 		trace_function(tr, ip, parent_ip, trace_ctx);
 
@@ -300,7 +298,6 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
 	unsigned int trace_ctx;
 	unsigned long flags;
 	int bit;
-	int cpu;
 
 	if (unlikely(!tr->function_enabled))
 		return;
@@ -309,8 +306,7 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
 	if (bit < 0)
 		return;
 
-	cpu = smp_processor_id();
-	data = per_cpu_ptr(tr->array_buffer.data, cpu);
+	data = this_cpu_ptr(tr->array_buffer.data);
 	if (atomic_read(&data->disabled))
 		goto out;
 
@@ -321,7 +317,7 @@ function_no_repeats_trace_call(unsigned long ip, unsigned long parent_ip,
 	 * TODO: think about a solution that is better than just hoping to be
 	 * lucky.
 	 */
-	last_info = per_cpu_ptr(tr->last_func_repeats, cpu);
+	last_info = this_cpu_ptr(tr->last_func_repeats);
 	if (is_repeat_check(tr, last_info, ip, parent_ip))
 		goto out;