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 76059C433EF for ; Tue, 11 Jan 2022 18:12:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233632AbiAKSMU (ORCPT ); Tue, 11 Jan 2022 13:12:20 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:20527 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243701AbiAKSMU (ORCPT ); Tue, 11 Jan 2022 13:12:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641924739; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=unAIvjnusz8VbzzgZbifDy0WCsnXknUvxf3V3Nius8k=; b=DxspO3eWPsFy7Q5v9bqZzdALqvspLSzRVhBj8OoNP12/Veve+rs20bK1RA6aP1uiz1kECo y63MHb+21DEdSFueXFaaQL7WHq9mjM2enlSkuA+eq3e23AcbGP6zq/iRIJlzoNUBcwM0Nr YU8YARz7PjDdGU0Tqeh3RpGvdcwz1nI= 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-376-CmtqQZj6N-adXsFkjRY4Rw-1; Tue, 11 Jan 2022 13:12:16 -0500 X-MC-Unique: CmtqQZj6N-adXsFkjRY4Rw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5194D104FC11; Tue, 11 Jan 2022 18:12:15 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8F713108F844; Tue, 11 Jan 2022 18:12:10 +0000 (UTC) From: Jeff Moyer To: Ming Lei Cc: Jens Axboe , Mike Snitzer , linux-block@vger.kernel.org, dm-devel@redhat.com Subject: Re: [dm-devel] [PATCH 3/3] dm: mark dm queue as blocking if any underlying is blocking References: <20211221141459.1368176-1-ming.lei@redhat.com> <20211221141459.1368176-4-ming.lei@redhat.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Tue, 11 Jan 2022 13:14:41 -0500 In-Reply-To: <20211221141459.1368176-4-ming.lei@redhat.com> (Ming Lei's message of "Tue, 21 Dec 2021 22:14:59 +0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Ming Lei writes: > dm request based driver doesn't set BLK_MQ_F_BLOCKING, so dm_queue_rq() > is supposed to not sleep. > > However, blk_insert_cloned_request() is used by dm_queue_rq() for > queuing underlying request, but the underlying queue may be marked as > BLK_MQ_F_BLOCKING, so blk_insert_cloned_request() may become to block > current context, then rcu warning is triggered. > > Fixes the issue by marking dm request based queue as BLK_MQ_F_BLOCKING > if any underlying queue is marked as BLK_MQ_F_BLOCKING, meantime we > need to allocate srcu beforehand. > > Signed-off-by: Ming Lei Acked-by: Jeff Moyer > --- > drivers/md/dm-rq.c | 5 ++++- > drivers/md/dm-rq.h | 3 ++- > drivers/md/dm-table.c | 14 ++++++++++++++ > drivers/md/dm.c | 5 +++-- > drivers/md/dm.h | 1 + > 5 files changed, 24 insertions(+), 4 deletions(-) > > diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c > index 579ab6183d4d..2297d37c62a9 100644 > --- a/drivers/md/dm-rq.c > +++ b/drivers/md/dm-rq.c > @@ -535,7 +535,8 @@ static const struct blk_mq_ops dm_mq_ops = { > .init_request = dm_mq_init_request, > }; > > -int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) > +int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t, > + bool blocking) > { > struct dm_target *immutable_tgt; > int err; > @@ -550,6 +551,8 @@ int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) > md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING; > md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues(); > md->tag_set->driver_data = md; > + if (blocking) > + md->tag_set->flags |= BLK_MQ_F_BLOCKING; > > md->tag_set->cmd_size = sizeof(struct dm_rq_target_io); > immutable_tgt = dm_table_get_immutable_target(t); > diff --git a/drivers/md/dm-rq.h b/drivers/md/dm-rq.h > index 1eea0da641db..5f3729f277d7 100644 > --- a/drivers/md/dm-rq.h > +++ b/drivers/md/dm-rq.h > @@ -30,7 +30,8 @@ struct dm_rq_clone_bio_info { > struct bio clone; > }; > > -int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t); > +int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t, > + bool blocking); > void dm_mq_cleanup_mapped_device(struct mapped_device *md); > > void dm_start_queue(struct request_queue *q); > diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c > index aa173f5bdc3d..e4bdd4f757a3 100644 > --- a/drivers/md/dm-table.c > +++ b/drivers/md/dm-table.c > @@ -1875,6 +1875,20 @@ static bool dm_table_supports_write_zeroes(struct dm_table *t) > return true; > } > > +/* If the device can block inside ->queue_rq */ > +static int device_is_io_blocking(struct dm_target *ti, struct dm_dev *dev, > + sector_t start, sector_t len, void *data) > +{ > + struct request_queue *q = bdev_get_queue(dev->bdev); > + > + return blk_queue_blocking(q); > +} > + > +bool dm_table_has_blocking_dev(struct dm_table *t) > +{ > + return dm_table_any_dev_attr(t, device_is_io_blocking, NULL); > +} > + > static int device_not_nowait_capable(struct dm_target *ti, struct dm_dev *dev, > sector_t start, sector_t len, void *data) > { > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index 280918cdcabd..2f72877752dd 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -1761,7 +1761,7 @@ static struct mapped_device *alloc_dev(int minor) > * established. If request-based table is loaded: blk-mq will > * override accordingly. > */ > - md->disk = blk_alloc_disk(md->numa_node_id); > + md->disk = blk_alloc_disk_srcu(md->numa_node_id); > if (!md->disk) > goto bad; > md->queue = md->disk->queue; > @@ -2046,7 +2046,8 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t) > switch (type) { > case DM_TYPE_REQUEST_BASED: > md->disk->fops = &dm_rq_blk_dops; > - r = dm_mq_init_request_queue(md, t); > + r = dm_mq_init_request_queue(md, t, > + dm_table_has_blocking_dev(t)); > if (r) { > DMERR("Cannot initialize queue for request-based dm mapped device"); > return r; > diff --git a/drivers/md/dm.h b/drivers/md/dm.h > index 742d9c80efe1..f7f92b272cce 100644 > --- a/drivers/md/dm.h > +++ b/drivers/md/dm.h > @@ -60,6 +60,7 @@ int dm_calculate_queue_limits(struct dm_table *table, > struct queue_limits *limits); > int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, > struct queue_limits *limits); > +bool dm_table_has_blocking_dev(struct dm_table *t); > struct list_head *dm_table_get_devices(struct dm_table *t); > void dm_table_presuspend_targets(struct dm_table *t); > void dm_table_presuspend_undo_targets(struct dm_table *t);