writeback: remove broken rbtree_postorder_for_each_entry_safe() usage in cgwb_bdi_des...
authorTejun Heo <tj@kernel.org>
Tue, 13 Oct 2015 22:14:19 +0000 (18:14 -0400)
committerJens Axboe <axboe@fb.com>
Wed, 21 Oct 2015 14:17:29 +0000 (08:17 -0600)
commite27c5b9d23168cc2cb8fec147ae7ed1f7a2005c3
treed7ed4b0682df716b85b14e09e3da6337b2ee9f1d
parent0dfc70c33409afc232ef0b9ec210535dfbf9bc61
writeback: remove broken rbtree_postorder_for_each_entry_safe() usage in cgwb_bdi_destroy()

a20135ffbc44 ("writeback: don't drain bdi_writeback_congested on bdi
destruction") added rbtree_postorder_for_each_entry_safe() which is
used to remove all entries; however, according to Cody, the iterator
isn't safe against operations which may rebalance the tree.  Fix it by
switching to repeatedly removing rb_first() until empty.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Cody P Schafer <dev@codyps.com>
Fixes: a20135ffbc44 ("writeback: don't drain bdi_writeback_congested on bdi destruction")
Link: http://lkml.kernel.org/g/1443997973-1700-1-git-send-email-dev@codyps.com
Signed-off-by: Jens Axboe <axboe@fb.com>
mm/backing-dev.c