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| author | Tejun Heo <tj@kernel.org> | 2015-10-13 18:14:19 -0400 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-10-21 08:17:29 -0600 |
| commit | e27c5b9d23168cc2cb8fec147ae7ed1f7a2005c3 (patch) | |
| tree | d7ed4b0682df716b85b14e09e3da6337b2ee9f1d /mm/backing-dev.c | |
| parent | 0dfc70c33409afc232ef0b9ec210535dfbf9bc61 (diff) | |
| download | lwn-e27c5b9d23168cc2cb8fec147ae7ed1f7a2005c3.tar.gz lwn-e27c5b9d23168cc2cb8fec147ae7ed1f7a2005c3.zip | |
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>
Diffstat (limited to 'mm/backing-dev.c')
| -rw-r--r-- | mm/backing-dev.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 9e841399041a..619984fc07ec 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -681,7 +681,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi) static void cgwb_bdi_destroy(struct backing_dev_info *bdi) { struct radix_tree_iter iter; - struct bdi_writeback_congested *congested, *congested_n; + struct rb_node *rbn; void **slot; WARN_ON(test_bit(WB_registered, &bdi->wb.state)); @@ -691,9 +691,11 @@ static void cgwb_bdi_destroy(struct backing_dev_info *bdi) radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0) cgwb_kill(*slot); - rbtree_postorder_for_each_entry_safe(congested, congested_n, - &bdi->cgwb_congested_tree, rb_node) { - rb_erase(&congested->rb_node, &bdi->cgwb_congested_tree); + while ((rbn = rb_first(&bdi->cgwb_congested_tree))) { + struct bdi_writeback_congested *congested = + rb_entry(rbn, struct bdi_writeback_congested, rb_node); + + rb_erase(rbn, &bdi->cgwb_congested_tree); congested->bdi = NULL; /* mark @congested unlinked */ } |