From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40A8DC433F5 for ; Sat, 22 Jan 2022 11:12:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230226AbiAVLM6 (ORCPT ); Sat, 22 Jan 2022 06:12:58 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:50355 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230400AbiAVLM6 (ORCPT ); Sat, 22 Jan 2022 06:12:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1642849977; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=G+NRXXc+hwDjuvMZtnwreB6eugOj8g0/jJ/eXBY93LM=; b=FuLc8ZE9VS9Vr+H2iyj+cEwBwNm+ToJlLdWK9Rcg0gWcmmhP+VxwwK2sXCR1PKsnRNizdw 7fE1T8Ru2W6q7NNEazMiL/8ekerY6jchG9exa8rwQQ2lmLs0nt2gls+Cq9beVxhNUUI/Sz MOREVcOF5CAmBGEN/OQeMxbV0Fg+Wjk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-222-dQCM9ynzOlCq1WlgVh7rGg-1; Sat, 22 Jan 2022 06:12:52 -0500 X-MC-Unique: dQCM9ynzOlCq1WlgVh7rGg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B281818397A7; Sat, 22 Jan 2022 11:12:51 +0000 (UTC) Received: from localhost (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id F0E7D752CF; Sat, 22 Jan 2022 11:12:47 +0000 (UTC) From: Ming Lei To: Christoph Hellwig , Jens Axboe , "Martin K . Petersen" Cc: linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, Ming Lei Subject: [PATCH V2 13/13] block: don't drain file system I/O on del_gendisk Date: Sat, 22 Jan 2022 19:10:54 +0800 Message-Id: <20220122111054.1126146-14-ming.lei@redhat.com> In-Reply-To: <20220122111054.1126146-1-ming.lei@redhat.com> References: <20220122111054.1126146-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Commit 8e141f9eb803 ("block: drain file system I/O on del_gendisk") is added for avoiding to reference of q->disk after disk is released, since disk release can be done before running into blk_cleanup_queue(), but it can't avoid the issue completely, and the approach is very fragile: 1) queue freezing can't drain FS I/O for bio based driver, so there is still inflight bios after disk is deleted, so blk-cgroup shutdown can't be moved to del_gendisk(); meantime elevator shutdown can't be moved to del_gendisk() because freezing queue isn't enough to drain io issue activities. So both block-cgroup and elevator code may still refer to q->disk somewhere. Same with q->disk referring for bio based driver. 2) the added flag of GD_DEAD may not be observed reliably in __bio_queue_enter() because queue freezing might not imply rcu grace period. Now we have moved blkcg, rqos and elevator shutdown code into disk_release() where it is guaranteed that no any FS IO is inflight. Meantime we only account passthrough IO issued from userspace, where q->disk is always valid. Then q->disk can be guaranteed to be referred before releasing disk. So not necessary to drain FS I/O in del_gendisk() any more. Signed-off-by: Ming Lei --- block/blk-core.c | 21 +++++++++------------ block/blk.h | 1 - block/genhd.c | 21 --------------------- include/linux/genhd.h | 1 - 4 files changed, 9 insertions(+), 35 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index bcb4d982cd80..2216360165c9 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -270,8 +270,10 @@ void blk_put_queue(struct request_queue *q) } EXPORT_SYMBOL(blk_put_queue); -void blk_queue_start_drain(struct request_queue *q) +void blk_set_queue_dying(struct request_queue *q) { + blk_queue_flag_set(QUEUE_FLAG_DYING, q); + /* * When queue DYING flag is set, we need to block new req * entering queue, so we call blk_freeze_queue_start() to @@ -283,12 +285,6 @@ void blk_queue_start_drain(struct request_queue *q) /* Make blk_queue_enter() reexamine the DYING flag. */ wake_up_all(&q->mq_freeze_wq); } - -void blk_set_queue_dying(struct request_queue *q) -{ - blk_queue_flag_set(QUEUE_FLAG_DYING, q); - blk_queue_start_drain(q); -} EXPORT_SYMBOL_GPL(blk_set_queue_dying); /** @@ -322,6 +318,9 @@ void blk_cleanup_queue(struct request_queue *q) blk_queue_flag_set(QUEUE_FLAG_DEAD, q); + /* for synchronous bio-based driver finish in-flight integrity i/o */ + blk_flush_integrity(); + blk_sync_queue(q); if (queue_is_mq(q)) { blk_mq_cancel_work_sync(q); @@ -381,10 +380,8 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) int __bio_queue_enter(struct request_queue *q, struct bio *bio) { while (!blk_try_enter_queue(q, false)) { - struct gendisk *disk = bio->bi_bdev->bd_disk; - if (bio->bi_opf & REQ_NOWAIT) { - if (test_bit(GD_DEAD, &disk->state)) + if (blk_queue_dying(q)) goto dead; bio_wouldblock_error(bio); return -EBUSY; @@ -401,8 +398,8 @@ int __bio_queue_enter(struct request_queue *q, struct bio *bio) wait_event(q->mq_freeze_wq, (!q->mq_freeze_depth && blk_pm_resume_queue(false, q)) || - test_bit(GD_DEAD, &disk->state)); - if (test_bit(GD_DEAD, &disk->state)) + blk_queue_dying(q)); + if (blk_queue_dying(q)) goto dead; } diff --git a/block/blk.h b/block/blk.h index a038e25d8637..6adedf97cba2 100644 --- a/block/blk.h +++ b/block/blk.h @@ -43,7 +43,6 @@ struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size, void blk_free_flush_queue(struct blk_flush_queue *q); void blk_freeze_queue(struct request_queue *q); -void blk_queue_start_drain(struct request_queue *q); int __bio_queue_enter(struct request_queue *q, struct bio *bio); bool submit_bio_checks(struct bio *bio); diff --git a/block/genhd.c b/block/genhd.c index 2f0e92cdcf6d..90742679f949 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -569,8 +569,6 @@ EXPORT_SYMBOL(device_add_disk); */ void del_gendisk(struct gendisk *disk) { - struct request_queue *q = disk->queue; - might_sleep(); if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN))) @@ -587,17 +585,8 @@ void del_gendisk(struct gendisk *disk) fsync_bdev(disk->part0); __invalidate_device(disk->part0, true); - /* - * Fail any new I/O. - */ - set_bit(GD_DEAD, &disk->state); set_capacity(disk, 0); - /* - * Prevent new I/O from crossing bio_queue_enter(). - */ - blk_queue_start_drain(q); - if (!(disk->flags & GENHD_FL_HIDDEN)) { sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); @@ -619,16 +608,6 @@ void del_gendisk(struct gendisk *disk) sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); device_del(disk_to_dev(disk)); - - blk_mq_freeze_queue_wait(q); - - blk_sync_queue(q); - blk_flush_integrity(); - /* - * Allow using passthrough request again after the queue is torn down. - */ - __blk_mq_unfreeze_queue(q, true); - } EXPORT_SYMBOL(del_gendisk); diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 6906a45bc761..3e9f234495e4 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -108,7 +108,6 @@ struct gendisk { unsigned long state; #define GD_NEED_PART_SCAN 0 #define GD_READ_ONLY 1 -#define GD_DEAD 2 #define GD_NATIVE_CAPACITY 3 struct mutex open_mutex; /* open/close mutex */ -- 2.31.1