From patchwork Sun Nov 8 19:28:17 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 7579381 Return-Path: X-Original-To: patchwork-linux-block@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 05FD09F392 for ; Sun, 8 Nov 2015 19:34:03 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E997520591 for ; Sun, 8 Nov 2015 19:34:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B7E932058A for ; Sun, 8 Nov 2015 19:34:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751761AbbKHTeA (ORCPT ); Sun, 8 Nov 2015 14:34:00 -0500 Received: from mga03.intel.com ([134.134.136.65]:55899 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751649AbbKHTeA (ORCPT ); Sun, 8 Nov 2015 14:34:00 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP; 08 Nov 2015 11:34:00 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,263,1444719600"; d="scan'208";a="846146101" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.39]) by fmsmga002.fm.intel.com with ESMTP; 08 Nov 2015 11:33:59 -0800 Subject: [PATCH v4 10/14] block: notify queue death confirmation From: Dan Williams To: axboe@fb.com Cc: Jens Axboe , jack@suse.cz, linux-nvdimm@lists.01.org, david@fromorbit.com, linux-block@vger.kernel.org, ross.zwisler@linux.intel.com, hch@lst.de Date: Sun, 08 Nov 2015 14:28:17 -0500 Message-ID: <20151108192817.9104.15236.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <20151108192722.9104.86664.stgit@dwillia2-desk3.amr.corp.intel.com> References: <20151108192722.9104.86664.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The pmem driver arranges for references to be taken against the queue while pages it allocated via devm_memremap_pages() are in use. At shutdown time, before those pages can be deallocated, they need to be unmapped, and guaranteed to be idle. The unmap scan can only be done once we are certain no new page references will be taken. Once the blk queue percpu_ref is confirmed dead the dax core will cease allowing new references and we can free these "device" pages. Cc: Jens Axboe Cc: Christoph Hellwig Cc: Ross Zwisler Signed-off-by: Dan Williams --- block/blk-core.c | 12 +++++++++--- block/blk-mq.c | 19 +++++++++++++++---- include/linux/blkdev.h | 4 +++- 3 files changed, 27 insertions(+), 8 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/block/blk-core.c b/block/blk-core.c index 6ebe33ed5154..5159946a2b41 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -516,6 +516,12 @@ void blk_set_queue_dying(struct request_queue *q) } EXPORT_SYMBOL_GPL(blk_set_queue_dying); +void blk_wait_queue_dead(struct request_queue *q) +{ + wait_event(q->q_freeze_wq, q->q_usage_dead); +} +EXPORT_SYMBOL(blk_wait_queue_dead); + /** * blk_cleanup_queue - shutdown a request queue * @q: request queue to shutdown @@ -641,7 +647,7 @@ int blk_queue_enter(struct request_queue *q, gfp_t gfp) if (!(gfp & __GFP_WAIT)) return -EBUSY; - ret = wait_event_interruptible(q->mq_freeze_wq, + ret = wait_event_interruptible(q->q_freeze_wq, !atomic_read(&q->mq_freeze_depth) || blk_queue_dying(q)); if (blk_queue_dying(q)) @@ -661,7 +667,7 @@ static void blk_queue_usage_counter_release(struct percpu_ref *ref) struct request_queue *q = container_of(ref, struct request_queue, q_usage_counter); - wake_up_all(&q->mq_freeze_wq); + wake_up_all(&q->q_freeze_wq); } struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) @@ -723,7 +729,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) q->bypass_depth = 1; __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags); - init_waitqueue_head(&q->mq_freeze_wq); + init_waitqueue_head(&q->q_freeze_wq); /* * Init percpu_ref in atomic mode so that it's faster to shutdown. diff --git a/block/blk-mq.c b/block/blk-mq.c index 6c240712553a..e0417febbcd4 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -78,13 +78,23 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, clear_bit(CTX_TO_BIT(hctx, ctx), &bm->word); } +static void blk_confirm_queue_death(struct percpu_ref *ref) +{ + struct request_queue *q = container_of(ref, typeof(*q), + q_usage_counter); + + q->q_usage_dead = 1; + wake_up_all(&q->q_freeze_wq); +} + void blk_mq_freeze_queue_start(struct request_queue *q) { int freeze_depth; freeze_depth = atomic_inc_return(&q->mq_freeze_depth); if (freeze_depth == 1) { - percpu_ref_kill(&q->q_usage_counter); + percpu_ref_kill_and_confirm(&q->q_usage_counter, + blk_confirm_queue_death); blk_mq_run_hw_queues(q, false); } } @@ -92,7 +102,7 @@ EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start); static void blk_mq_freeze_queue_wait(struct request_queue *q) { - wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter)); + wait_event(q->q_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter)); } /* @@ -130,7 +140,8 @@ void blk_mq_unfreeze_queue(struct request_queue *q) WARN_ON_ONCE(freeze_depth < 0); if (!freeze_depth) { percpu_ref_reinit(&q->q_usage_counter); - wake_up_all(&q->mq_freeze_wq); + q->q_usage_dead = 0; + wake_up_all(&q->q_freeze_wq); } } EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); @@ -149,7 +160,7 @@ void blk_mq_wake_waiters(struct request_queue *q) * dying, we need to ensure that processes currently waiting on * the queue are notified as well. */ - wake_up_all(&q->mq_freeze_wq); + wake_up_all(&q->q_freeze_wq); } bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index b78e01542e9e..e121e5e0c6ac 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -431,6 +431,7 @@ struct request_queue { */ unsigned int flush_flags; unsigned int flush_not_queueable:1; + unsigned int q_usage_dead:1; struct blk_flush_queue *fq; struct list_head requeue_list; @@ -453,7 +454,7 @@ struct request_queue { struct throtl_data *td; #endif struct rcu_head rcu_head; - wait_queue_head_t mq_freeze_wq; + wait_queue_head_t q_freeze_wq; struct percpu_ref q_usage_counter; struct list_head all_q_node; @@ -953,6 +954,7 @@ extern struct request_queue *blk_init_queue_node(request_fn_proc *rfn, extern struct request_queue *blk_init_queue(request_fn_proc *, spinlock_t *); extern struct request_queue *blk_init_allocated_queue(struct request_queue *, request_fn_proc *, spinlock_t *); +extern void blk_wait_queue_dead(struct request_queue *q); extern void blk_cleanup_queue(struct request_queue *); extern void blk_queue_make_request(struct request_queue *, make_request_fn *); extern void blk_queue_bounce_limit(struct request_queue *, u64);