[PATCH 09/13] android: binder: add function for finding prior thread in transaction stack

[Riley Andrews <riandrews@android.com>]

Add a helper function to find a thread within a transaction stack.

Signed-off-by: Riley Andrews <riandrews@android.com>
---
 drivers/android/binder.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index f7f2217..abd5556 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -1634,6 +1634,19 @@ static int binder_tr_validate_stack(struct binder_thread *thread)
 	return BR_OK;
 }
 
+struct binder_thread *binder_find_used_thread(struct binder_proc *proc,
+					      struct binder_transaction *stack)
+{
+	struct binder_transaction *tr = stack;
+
+	while (tr) {
+		if (tr->from && tr->from->proc == proc)
+			return tr->from;
+		tr = tr->from_parent;
+	}
+	return NULL;
+}
+
 static void binder_transaction(struct binder_thread *thread,
 			       struct binder_transaction_data *tr, int reply)
 {
@@ -1688,18 +1701,12 @@ static void binder_transaction(struct binder_thread *thread,
 			goto err_invalid_target_handle;
 		}
 		if (!(tr->flags & TF_ONE_WAY) && thread->transaction_stack) {
-			struct binder_transaction *tmp;
-
 			return_error = binder_tr_validate_stack(thread);
 			if (return_error != BR_OK)
 				goto err_bad_call_stack;
 
-			tmp = thread->transaction_stack;
-			while (tmp) {
-				if (tmp->from && tmp->from->proc == target_proc)
-					target_thread = tmp->from;
-				tmp = tmp->from_parent;
-			}
+			target_thread = binder_find_used_thread(target_proc,
+						thread->transaction_stack);
 		}
 	}
 	if (target_thread) {
-- 
2.2.0.rc0.207.ga3a616c