Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946021AbbFSVO1 (ORCPT ); Fri, 19 Jun 2015 17:14:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51679 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756155AbbFSUjS (ORCPT ); Fri, 19 Jun 2015 16:39:18 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Snitzer , "Peter Zijlstra (Intel)" , Dan Williams , Nicholas Moulin , NeilBrown , Christoph Hellwig , Jens Axboe Subject: [PATCH 4.0 057/105] block: discard bdi_unregister() in favour of bdi_destroy() Date: Fri, 19 Jun 2015 13:35:47 -0700 Message-Id: <20150619203559.879535864@linuxfoundation.org> X-Mailer: git-send-email 2.4.4 In-Reply-To: <20150619203558.187802739@linuxfoundation.org> References: <20150619203558.187802739@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4258 Lines: 119 4.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit aad653a0bc09dd4ebcb5579f9f835bbae9ef2ba3 upstream. bdi_unregister() now contains very little functionality. It contains a "WARN_ON" if bdi->dev is NULL. This warning is of no real consequence as bdi->dev isn't needed by anything else in the function, and it triggers if blk_cleanup_queue() -> bdi_destroy() is called before bdi_unregister, which happens since Commit: 6cd18e711dd8 ("block: destroy bdi before blockdev is unregistered.") So this isn't wanted. It also calls bdi_set_min_ratio(). This needs to be called after writes through the bdi have all been flushed, and before the bdi is destroyed. Calling it early is better than calling it late as it frees up a global resource. Calling it immediately after bdi_wb_shutdown() in bdi_destroy() perfectly fits these requirements. So bdi_unregister() can be discarded with the important content moved to bdi_destroy(), as can the writeback_bdi_unregister event which is already not used. Reported-by: Mike Snitzer Fixes: c4db59d31e39 ("fs: don't reassign dirty inodes to default_backing_dev_info") Fixes: 6cd18e711dd8 ("block: destroy bdi before blockdev is unregistered.") Acked-by: Peter Zijlstra (Intel) Acked-by: Dan Williams Tested-by: Nicholas Moulin Signed-off-by: NeilBrown Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/genhd.c | 1 - include/linux/backing-dev.h | 1 - include/trace/events/writeback.h | 1 - mm/backing-dev.c | 18 +----------------- 4 files changed, 1 insertion(+), 20 deletions(-) --- a/block/genhd.c +++ b/block/genhd.c @@ -653,7 +653,6 @@ void del_gendisk(struct gendisk *disk) disk->flags &= ~GENHD_FL_UP; sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); - bdi_unregister(&disk->queue->backing_dev_info); blk_unregister_queue(disk); blk_unregister_region(disk_devt(disk), disk->minors); --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -116,7 +116,6 @@ __printf(3, 4) int bdi_register(struct backing_dev_info *bdi, struct device *parent, const char *fmt, ...); int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); -void bdi_unregister(struct backing_dev_info *bdi); int __must_check bdi_setup_and_register(struct backing_dev_info *, char *); void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, enum wb_reason reason); --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -233,7 +233,6 @@ DEFINE_EVENT(writeback_class, name, \ DEFINE_WRITEBACK_EVENT(writeback_nowork); DEFINE_WRITEBACK_EVENT(writeback_wake_background); DEFINE_WRITEBACK_EVENT(writeback_bdi_register); -DEFINE_WRITEBACK_EVENT(writeback_bdi_unregister); DECLARE_EVENT_CLASS(wbc_class, TP_PROTO(struct writeback_control *wbc, struct backing_dev_info *bdi), --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -359,23 +359,6 @@ static void bdi_wb_shutdown(struct backi flush_delayed_work(&bdi->wb.dwork); } -/* - * Called when the device behind @bdi has been removed or ejected. - * - * We can't really do much here except for reducing the dirty ratio at - * the moment. In the future we should be able to set a flag so that - * the filesystem can handle errors at mark_inode_dirty time instead - * of only at writeback time. - */ -void bdi_unregister(struct backing_dev_info *bdi) -{ - if (WARN_ON_ONCE(!bdi->dev)) - return; - - bdi_set_min_ratio(bdi, 0); -} -EXPORT_SYMBOL(bdi_unregister); - static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi) { memset(wb, 0, sizeof(*wb)); @@ -443,6 +426,7 @@ void bdi_destroy(struct backing_dev_info int i; bdi_wb_shutdown(bdi); + bdi_set_min_ratio(bdi, 0); WARN_ON(!list_empty(&bdi->work_list)); WARN_ON(delayed_work_pending(&bdi->wb.dwork)); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/