From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752917AbaIGXER (ORCPT ); Sun, 7 Sep 2014 19:04:17 -0400 Received: from mail-pd0-f170.google.com ([209.85.192.170]:38809 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751947AbaIGXEO (ORCPT ); Sun, 7 Sep 2014 19:04:14 -0400 From: Tejun Heo To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 4/6] bdi: make backing_dev_info->wb.dwork canceling stricter Date: Mon, 8 Sep 2014 08:03:59 +0900 Message-Id: <1410131041-1881-5-git-send-email-tj@kernel.org> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1410131041-1881-1-git-send-email-tj@kernel.org> References: <1410131041-1881-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- mm/backing-dev.c | 15 ++------------- 1 file 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]); -- 1.9.3