From 001fe6f617b1a352ad29cc3643384b3d8141dc07 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Fri, 22 May 2015 17:13:56 -0400
Subject: [PATCH] writeback: make wakeup_dirtytime_writeback() handle multiple
 bdi_writeback's

wakeup_dirtytime_writeback() currently only starts writeback on the
root wb (bdi_writeback).  For cgroup writeback support, update the
function to check all wbs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jan Kara <jack@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jens Axboe <axboe@fb.com>
---
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