Patch "binder: Use wake up hint for synchronous transactions." has been added to the 4.4-stable tree

Patch "binder: Use wake up hint for synchronous transactions." has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    binder: Use wake up hint for synchronous transactions.

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     binder-use-wake-up-hint-for-synchronous-transactions.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 00b40d613352c623aaae88a44e5ded7c912909d7 Mon Sep 17 00:00:00 2001
From: Riley Andrews <riandrews@google.com>
Date: Thu, 29 Jun 2017 12:01:37 -0700
Subject: binder: Use wake up hint for synchronous transactions.

From: Riley Andrews <riandrews@google.com>

commit 00b40d613352c623aaae88a44e5ded7c912909d7 upstream.

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 <tkjos@google.com>
Signed-off-by: Omprakash Dhyade <odhyade@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/android/binder.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -1718,8 +1718,12 @@ static void binder_transaction(struct bi
 	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_get_unused_fd_failed:


Patches currently in stable-queue which might be from riandrews@google.com are

queue-4.4/binder-use-wake-up-hint-for-synchronous-transactions.patch