From: Riley Andrews <riandr...@google.com>

Use wake_up_interruptible_sync() to hint to the scheduler binder
transactions are synchronous wakeups. Disable preemption while waking
to avoid ping-ponging on the binder lock.

Signed-off-by: Todd Kjos <tk...@google.com>
Signed-off-by: Omprakash Dhyade <odhy...@codeaurora.org>
---
 drivers/android/binder.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 9393924ae8e8..f7665c31feca 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2200,8 +2200,12 @@ static void binder_transaction(struct binder_proc *proc,
        list_add_tail(&t->work.entry, target_list);
        tcomplete->type = BINDER_WORK_TRANSACTION_COMPLETE;
        list_add_tail(&tcomplete->entry, &thread->todo);
-       if (target_wait)
-               wake_up_interruptible(target_wait);
+       if (target_wait) {
+               if (reply || !(t->flags & TF_ONE_WAY))
+                       wake_up_interruptible_sync(target_wait);
+               else
+                       wake_up_interruptible(target_wait);
+       }
        return;
 
 err_translate_failed:
-- 
2.13.2.725.g09c95d1e9-goog

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