tracing: Move trace_flags from global to a trace_array field

In preparation to make trace options per instance, the global trace_flags
needs to be moved from being a global variable to a field within the trace
instance trace_array structure.

There's still more work to do, as there's some functions that use
trace_flags without passing in a way to get to the current_trace array. For
those, the global_trace is used directly (from trace.c). This includes
setting and clearing the trace_flags. This means that when a new instance is
created, it just gets the trace_flags of the global_trace and will not be
able to modify them. Depending on the functions that have access to the
trace_array, the flags of an instance may not affect parts of its trace,
where the global_trace is used. These will be fixed in future changes.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_kdb.c

@@ -21,20 +21,22 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
 	/* use static because iter can be a bit big for the stack */
 	static struct trace_iterator iter;
 	static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
+	struct trace_array *tr;
 	unsigned int old_userobj;
 	int cnt = 0, cpu;
 
 	trace_init_global_iter(&iter);
 	iter.buffer_iter = buffer_iter;
+	tr = iter.tr;
 
 	for_each_tracing_cpu(cpu) {
 		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
 	}
 
-	old_userobj = trace_flags;
+	old_userobj = tr->trace_flags;
 
 	/* don't look at user memory in panic mode */
-	trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
+	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
 
 	kdb_printf("Dumping ftrace buffer:\n");
 
@@ -82,7 +84,7 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
 		kdb_printf("---------------------------------\n");
 
 out:
-	trace_flags = old_userobj;
+	tr->trace_flags = old_userobj;
 
 	for_each_tracing_cpu(cpu) {
 		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);