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authorTejun Heo <tj@kernel.org>2014-09-08 08:03:59 +0900
committerJens Axboe <axboe@fb.com>2014-09-08 10:00:39 -0600
commitc0ea1c22bce63a27b47da90ad1ac49ce48e1a8aa (patch)
tree5a5fe4a6b86c4208afb3b812426dfb34f54ae75a /mm
parentb68757341d8015d28e261990deea58dd836e04da (diff)
downloadop-kernel-dev-c0ea1c22bce63a27b47da90ad1ac49ce48e1a8aa.zip
op-kernel-dev-c0ea1c22bce63a27b47da90ad1ac49ce48e1a8aa.tar.gz
bdi: make backing_dev_info->wb.dwork canceling stricter
Canceling of bdi->wb.dwork is currently a bit mushy. bdi_wb_shutdown() performs cancel_delayed_work_sync() at the end after shutting down and flushing the delayed_work and bdi_destroy() tries yet again after bdi_unregister(). bdi->wb.dwork is queued only after checking BDI_registered while holding bdi->wb_lock and bdi_wb_shutdown() clears the flag while holding the same lock and then flushes the delayed_work. There's no way the delayed_work can be queued again after that. Replace the two unnecessary cancel_delayed_work_sync() invocations with WARNs on pending. This simplifies and clarifies the code a bit and will help future changes in further isolating bdi_writeback handling. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/backing-dev.c15
1 files changed, 2 insertions, 13 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 4afeefe..cb7c5e3 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -376,13 +376,7 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi)
mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0);
flush_delayed_work(&bdi->wb.dwork);
WARN_ON(!list_empty(&bdi->work_list));
-
- /*
- * This shouldn't be necessary unless @bdi for some reason has
- * unflushed dirty IO after work_list is drained. Do it anyway
- * just in case.
- */
- cancel_delayed_work_sync(&bdi->wb.dwork);
+ WARN_ON(delayed_work_pending(&bdi->wb.dwork));
}
/*
@@ -497,12 +491,7 @@ void bdi_destroy(struct backing_dev_info *bdi)
bdi_unregister(bdi);
- /*
- * If bdi_unregister() had already been called earlier, the dwork
- * could still be pending because bdi_prune_sb() can race with the
- * bdi_wakeup_thread_delayed() calls from __mark_inode_dirty().
- */
- cancel_delayed_work_sync(&bdi->wb.dwork);
+ WARN_ON(delayed_work_pending(&bdi->wb.dwork));
for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
percpu_counter_destroy(&bdi->bdi_stat[i]);
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