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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C57ACC43334 for ; Tue, 5 Jul 2022 07:42:03 +0000 (UTC) Received: from localhost ([::1]:49542 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o8dC6-0001CI-LN for qemu-devel@archiver.kernel.org; Tue, 05 Jul 2022 03:42:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54452) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o8dA4-0008EX-N0 for qemu-devel@nongnu.org; Tue, 05 Jul 2022 03:39:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:29750) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o8dA2-0003s0-Cz for qemu-devel@nongnu.org; Tue, 05 Jul 2022 03:39:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657006793; 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=7SRr3hZjPpbBQFg0kpkKaskm4/fn5rwiS918fsItvYk=; b=KQ3hq+qX3fdJwHcB30kKVjhjmcnYD3Gwd5+hz4rErcHwn8Fx0zzD8W7QA3icIfL8hrwNwN 6nNl16Bbyr6E/wXoeuBC/0QHVXYqo90m6ZynudnLfsShWxHJttDDTzPgbwuG0RWU/Auohg EdUulS2pG0o0k53grOd81Pkv58toX/k= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-663-0DmTshyAP8uiHsSxVYgtHw-1; Tue, 05 Jul 2022 03:39:50 -0400 X-MC-Unique: 0DmTshyAP8uiHsSxVYgtHw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 25F73185A7A4; Tue, 5 Jul 2022 07:39:50 +0000 (UTC) Received: from localhost (unknown [10.39.194.109]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8242240CF8ED; Tue, 5 Jul 2022 07:39:49 +0000 (UTC) Date: Tue, 5 Jul 2022 08:39:48 +0100 From: Stefan Hajnoczi To: Emanuele Giuseppe Esposito Cc: qemu-block@nongnu.org, Kevin Wolf , Hanna Reitz , Paolo Bonzini , John Snow , Vladimir Sementsov-Ogievskiy , Wen Congyang , Xie Changlong , Markus Armbruster , Fam Zheng , qemu-devel@nongnu.org Subject: Re: [PATCH v8 05/20] job.c: add job_lock/unlock while keeping job.h intact Message-ID: References: <20220629141538.3400679-1-eesposit@redhat.com> <20220629141538.3400679-6-eesposit@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="sxUFBxAHt6ECUmvJ" Content-Disposition: inline In-Reply-To: <20220629141538.3400679-6-eesposit@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --sxUFBxAHt6ECUmvJ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Jun 29, 2022 at 10:15:23AM -0400, Emanuele Giuseppe Esposito wrote: > +void job_ref(Job *job) > +{ > + JOB_LOCK_GUARD(); > + job_ref_locked(job); > +} You don't need to fix this, but just a note: This API seems dangerous. If we don't hold the lock, how can we be sure job won't be unreferenced before we call job_ref()? We would need to be sure there exists another reference that won't be released until job_ref() returns... --sxUFBxAHt6ECUmvJ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmLD6sQACgkQnKSrs4Gr c8iqNggAqgJNJzZFoMHl+MHSzUiTCW41g1jC3Ji6o395de/28JkkreMb/UdeO2YH FShz7c8CgNUYa6wan8B3U0yh7mcoK/OMKkuko4amHkYkyTU3Jd1LwqvOKquFKQcy +17jsqQ5P7Bhps06hHVjF8jbhHCRhHjgrQieZSThFDgtcrtFb2gwdRNs9xTCBQAn rzC0MJkjSucwKNWsaGCGhu9pxyKYKop1nSvZUrXByfRlr8GZbMo09Pyj0oZgtEXx BUX5I7TqtYSCCOuIhdARgBc4o2Jbe6E0l2jV0yDDEel6AXYLAWyrfrq+wuuCF9Pf Zp87C+RTk6RbO+eRK0Dk6mXe9Ri4wQ== =p+RF -----END PGP SIGNATURE----- --sxUFBxAHt6ECUmvJ--