binder: Use wake up hint for synchronous transactions.

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 <[email protected]> Signed-off-by: Omprakash Dhyade <[email protected]> Cc: stable <[email protected]> # 4.4+ Signed-off-by: Greg Kroah-Hartman <[email protected]>
marcb · Jul 17, 2017 · 00b40d6 · 00b40d6
1 parent c4ea41b
commit 00b40d6
Showing 1 changed file with 6 additions and 2 deletions.
diff --git 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: