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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59BCAC4332F for ; Thu, 7 Oct 2021 12:03:44 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DC4A06103B for ; Thu, 7 Oct 2021 12:03:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DC4A06103B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:46282 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mYS7j-0003pF-4x for qemu-devel@archiver.kernel.org; Thu, 07 Oct 2021 08:03:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42150) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mYS5c-00023k-RR for qemu-devel@nongnu.org; Thu, 07 Oct 2021 08:01:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37678) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mYS5U-00038Z-NK for qemu-devel@nongnu.org; Thu, 07 Oct 2021 08:01:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633608082; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9Req2CBiecKu07DEdZfui/wjJRXyFApYGvN6Qq2DkWQ=; b=ieFm2/1AdHKxaVxi/QNR8P0dvjjO15Uu7eeUc5B9Bx7lPdS4Fhn/8/nvn0kzw6Aubh3mY9 hA6th4xNwBHvYNUV26OOmp7LTe8CsK/NtLIS9u6ODP2hTkngCPRPoDBgQJeqp4ezDX6aaS rXJAsuXIqnqLnWUpb6LZOElQn1sHT4M= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-529-3xpQLtD5Ngm245B1zwdEwg-1; Thu, 07 Oct 2021 08:01:05 -0400 X-MC-Unique: 3xpQLtD5Ngm245B1zwdEwg-1 Received: by mail-wr1-f69.google.com with SMTP id c2-20020adfa302000000b0015e4260febdso4475253wrb.20 for ; Thu, 07 Oct 2021 05:01:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=9Req2CBiecKu07DEdZfui/wjJRXyFApYGvN6Qq2DkWQ=; b=QvAxdTDuouX+mtFcyjLZlKM0gOAvn8C4cyVkOH3tBkaMR24Zn4u6Yqkp+IOjcMSIby WlNhvDVfz7FbQkouIZByIYW8hHCEkx5WvN6IizdFNPhwXLScNvyYJFDBM5TVznvVNbMt XsgYHFlpClCx6FnR9/balQeMdh4svgXgPgXvEHd/UQWDf/VI54gcMlE+rrtZk/9ByUEK JOqPyWAlewT5LY8409fYDOtkxpC9TPCtNkR8aLNjtEw9IJwtfRzQicW90N9b7/JNsrZL IR54/T5tBk1FT3R4S/61bF4evsAyMWMcm+8Z+oI0nNr/065zZHPtD8Rc/9VuQCFY4nJN l7uQ== X-Gm-Message-State: AOAM530SE2eZK5+m93+KIHc0i7dii7w8qkX3l0y2JfT2BC9wkVKOxRA5 KItb5ufNb6hzL/djf5MkRr5Vi3vvBJlpOjBuYTX8YCp5fILzHPeX2UOLnYSN4i7BzWVKYkw3Zyc /reuotpdmhA9nH24= X-Received: by 2002:a1c:2543:: with SMTP id l64mr15949255wml.9.1633608064201; Thu, 07 Oct 2021 05:01:04 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyLpdh1DyyKefDIhQfh9sNEs3QqzX59e/uKghVcZmgbs7s6bZ6DXQIRfj5Q5FCARldTYZfroQ== X-Received: by 2002:a1c:2543:: with SMTP id l64mr15949202wml.9.1633608063866; Thu, 07 Oct 2021 05:01:03 -0700 (PDT) Received: from ?IPV6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id r205sm4723242wma.3.2021.10.07.05.01.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Oct 2021 05:01:03 -0700 (PDT) Message-ID: Date: Thu, 7 Oct 2021 14:01:01 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 Subject: Re: [RFC PATCH v2 08/25] block: introduce assert_bdrv_graph_writable To: Emanuele Giuseppe Esposito , qemu-block@nongnu.org References: <20211005143215.29500-1-eesposit@redhat.com> <20211005143215.29500-9-eesposit@redhat.com> From: Paolo Bonzini In-Reply-To: <20211005143215.29500-9-eesposit@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pbonzini@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -47 X-Spam_score: -4.8 X-Spam_bar: ---- X-Spam_report: (-4.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.05, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-1.964, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , Vladimir Sementsov-Ogievskiy , =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , Eduardo Habkost , Juan Quintela , Eric Blake , Richard Henderson , qemu-devel@nongnu.org, Markus Armbruster , Hanna Reitz , Stefan Hajnoczi , John Snow , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 05/10/21 16:31, Emanuele Giuseppe Esposito wrote: > We want to be sure that the functions that write the child and > parent list of a bs are either under BQL or drain. > If this guarantee holds, then we can read the list also in the I/O APIs. > > Signed-off-by: Emanuele Giuseppe Esposito > --- > block.c | 5 +++++ > block/io.c | 5 +++++ > include/block/block_int-global-state.h | 8 +++++++- > 3 files changed, 17 insertions(+), 1 deletion(-) > > diff --git a/block.c b/block.c > index b912f517a4..7d1eb847a4 100644 > --- a/block.c > +++ b/block.c > @@ -2711,12 +2711,14 @@ static void bdrv_replace_child_noperm(BdrvChild *child, > if (child->klass->detach) { > child->klass->detach(child); > } > + assert_bdrv_graph_writable(old_bs); > QLIST_REMOVE(child, next_parent); > } > > child->bs = new_bs; > > if (new_bs) { > + assert_bdrv_graph_writable(new_bs); > QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); > > /* > @@ -2917,6 +2919,7 @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, > return ret; > } > > + assert_bdrv_graph_writable(parent_bs); > QLIST_INSERT_HEAD(&parent_bs->children, *child, next); > /* > * child is removed in bdrv_attach_child_common_abort(), so don't care to > @@ -3117,6 +3120,7 @@ static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child, > void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) > { > g_assert(qemu_in_main_thread()); > + assert_bdrv_graph_writable(parent); > if (child == NULL) { > return; > } > @@ -4878,6 +4882,7 @@ static void bdrv_remove_filter_or_cow_child_abort(void *opaque) > BdrvRemoveFilterOrCowChild *s = opaque; > BlockDriverState *parent_bs = s->child->opaque; > > + assert_bdrv_graph_writable(parent_bs); > QLIST_INSERT_HEAD(&parent_bs->children, s->child, next); > if (s->is_backing) { > parent_bs->backing = s->child; > diff --git a/block/io.c b/block/io.c > index 21dcc5d962..d184183b07 100644 > --- a/block/io.c > +++ b/block/io.c > @@ -739,6 +739,11 @@ void bdrv_drain_all(void) > bdrv_drain_all_end(); > } > > +void assert_bdrv_graph_writable(BlockDriverState *bs) > +{ > + g_assert(qatomic_read(&bs->quiesce_counter) > 0 || qemu_in_main_thread()); > +} > + > /** > * Remove an active request from the tracked requests list > * > diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h > index aad549cb85..a53ab146fc 100644 > --- a/include/block/block_int-global-state.h > +++ b/include/block/block_int-global-state.h > @@ -343,4 +343,10 @@ void bdrv_remove_aio_context_notifier(BlockDriverState *bs, > */ > void bdrv_drain_all_end_quiesce(BlockDriverState *bs); > > -#endif /* BLOCK_INT_GLOBAL_STATE*/ > +/** > + * Make sure that the function is either running under > + * drain, or under BQL. > + */ > +void assert_bdrv_graph_writable(BlockDriverState *bs); > + > +#endif /* BLOCK_INT_GLOBAL_STATE */ > Reviewed-by: Paolo Bonzini