From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758603Ab2BNBOd (ORCPT ); Mon, 13 Feb 2012 20:14:33 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:57106 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751161Ab2BNBOb (ORCPT ); Mon, 13 Feb 2012 20:14:31 -0500 Date: Mon, 13 Feb 2012 17:14:27 -0800 From: Tejun Heo To: Jens Axboe , linux-kernel@vger.kernel.org, Vivek Goyal Subject: [PATCH UPDATED block/for-linus] block: blk-throttle should be drained regardless of q->elevator Message-ID: <20120214011427.GJ12117@google.com> References: <20120213225248.GH12117@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120213225248.GH12117@google.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, blk_cleanup_queue() doesn't call elv_drain_elevator() if q->elevator doesn't exist; however, bio based drivers don't have elevator initialized but can still use blk-throttle. This patch moves q->elevator test inside blk_drain_queue() such that only elv_drain_elevator() is skipped if !q->elevator. -v2: loop can have registered queue which has NULL request_fn. Make sure we don't call into __blk_run_queue() in such cases. Signed-off-by: Tejun Heo Reported-by: Vivek Goyal Acked-by: Vivek Goyal --- Added check against NULL q->request_fn for loop driver. Thanks. block/blk-core.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) Index: work/block/blk-core.c =================================================================== --- work.orig/block/blk-core.c +++ work/block/blk-core.c @@ -365,17 +365,24 @@ void blk_drain_queue(struct request_queu spin_lock_irq(q->queue_lock); - elv_drain_elevator(q); + /* + * The caller might be trying to drain @q before its + * elevator is initialized. + */ + if (q->elevator) + elv_drain_elevator(q); + if (drain_all) blk_throtl_drain(q); /* * This function might be called on a queue which failed - * driver init after queue creation. Some drivers - * (e.g. fd) get unhappy in such cases. Kick queue iff - * dispatch queue has something on it. + * driver init after queue creation or is not yet fully + * active yet. Some drivers (e.g. fd and loop) get unhappy + * in such cases. Kick queue iff dispatch queue has + * something on it and @q has request_fn set. */ - if (!list_empty(&q->queue_head)) + if (!list_empty(&q->queue_head) && q->request_fn) __blk_run_queue(q); drain |= q->rq.elvpriv; @@ -428,13 +435,8 @@ void blk_cleanup_queue(struct request_qu spin_unlock_irq(lock); mutex_unlock(&q->sysfs_lock); - /* - * Drain all requests queued before DEAD marking. The caller might - * be trying to tear down @q before its elevator is initialized, in - * which case we don't want to call into draining. - */ - if (q->elevator) - blk_drain_queue(q, true); + /* drain all requests queued before DEAD marking */ + blk_drain_queue(q, true); /* @q won't process any more request, flush async actions */ del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);