perf thread: Adopt get_main_thread from db-export.c

Move the get_main_thread function from db-export.c to thread.c so that
it can be used elsewhere.

Signed-off-by: Andi Kleen <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
[ Removed leftover bits from db-export.h ]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/db-export.c

···
 	return 0;
 }
 
-static struct thread *get_main_thread(struct machine *machine, struct thread *thread)
-{
-	if (thread->pid_ == thread->tid)
-		return thread__get(thread);
-
-	if (thread->pid_ == -1)
-		return NULL;
-
-	return machine__find_thread(machine, thread->pid_, thread->pid_);
-}
-
 static int db_ids_from_al(struct db_export *dbe, struct addr_location *al,
 			  u64 *dso_db_id, u64 *sym_db_id, u64 *offset)
 {
···
 	if (err)
 		return err;
 
-	main_thread = get_main_thread(al->machine, thread);
+	main_thread = thread__main_thread(al->machine, thread);
 	if (main_thread)
 		comm = machine__thread_exec_comm(al->machine, main_thread);
 

tools/perf/util/thread.c

···
 			break;
 	}
 }
+
+struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
+{
+	if (thread->pid_ == thread->tid)
+		return thread__get(thread);
+
+	if (thread->pid_ == -1)
+		return NULL;
+
+	return machine__find_thread(machine, thread->pid_, thread->pid_);
+}

tools/perf/util/thread.h

···
 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp);
 size_t thread__fprintf(struct thread *thread, FILE *fp);
 
+struct thread *thread__main_thread(struct machine *machine, struct thread *thread);
+
 void thread__find_addr_map(struct thread *thread,
 			   u8 cpumode, enum map_type type, u64 addr,
 			   struct addr_location *al);