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 X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01785C49ED6 for ; Wed, 11 Sep 2019 17:41:47 +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 CE0032081B for ; Wed, 11 Sep 2019 17:41:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE0032081B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:54190 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i86cj-0000Vb-RL for qemu-devel@archiver.kernel.org; Wed, 11 Sep 2019 13:41:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52498) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i86bw-0008VF-8p for qemu-devel@nongnu.org; Wed, 11 Sep 2019 13:40:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i86bv-0002rs-0c for qemu-devel@nongnu.org; Wed, 11 Sep 2019 13:40:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44810) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i86bu-0002qt-P6 for qemu-devel@nongnu.org; Wed, 11 Sep 2019 13:40:54 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id B40B3190C102 for ; Wed, 11 Sep 2019 17:40:53 +0000 (UTC) Received: from [10.3.116.234] (ovpn-116-234.phx2.redhat.com [10.3.116.234]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D0EE45D9E2; Wed, 11 Sep 2019 17:40:52 +0000 (UTC) To: "Dr. David Alan Gilbert (git)" , qemu-devel@nongnu.org, pbonzini@redhat.com, berrange@redhat.com, quintela@redhat.com References: <20190911164202.31136-1-dgilbert@redhat.com> <20190911164202.31136-2-dgilbert@redhat.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: <1a03f787-5cf8-6b8e-7489-3f90c3311032@redhat.com> Date: Wed, 11 Sep 2019 12:40:51 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190911164202.31136-2-dgilbert@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="p71Il7lcb5yFZZddKSgj4mF1gpRtmyIcR" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.70]); Wed, 11 Sep 2019 17:40:53 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --p71Il7lcb5yFZZddKSgj4mF1gpRtmyIcR Content-Type: multipart/mixed; boundary="e5sPTJgMgEVwCS1SqBvaHOWCF1uM73jYm"; protected-headers="v1" From: Eric Blake To: "Dr. David Alan Gilbert (git)" , qemu-devel@nongnu.org, pbonzini@redhat.com, berrange@redhat.com, quintela@redhat.com Message-ID: <1a03f787-5cf8-6b8e-7489-3f90c3311032@redhat.com> Subject: Re: [Qemu-devel] [PATCH 1/3] rcu: Add automatically released rcu_read_lock variant References: <20190911164202.31136-1-dgilbert@redhat.com> <20190911164202.31136-2-dgilbert@redhat.com> In-Reply-To: <20190911164202.31136-2-dgilbert@redhat.com> --e5sPTJgMgEVwCS1SqBvaHOWCF1uM73jYm Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 9/11/19 11:42 AM, Dr. David Alan Gilbert (git) wrote: > From: "Dr. David Alan Gilbert" >=20 > RCU_READ_LOCK_AUTO takes the rcu_read_lock and then uses glib's > g_auto infrastrcture (and thus whatever the compilers hooks are) to > release it on all exits of the block. >=20 > Note this macro has a variable declaration in, and hence is not in > a while loop. >=20 > Signed-off-by: Dr. David Alan Gilbert > --- > include/qemu/rcu.h | 12 ++++++++++++ > 1 file changed, 12 insertions(+) >=20 > diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h > index 22876d1428..6a25b27d28 100644 > --- a/include/qemu/rcu.h > +++ b/include/qemu/rcu.h > @@ -154,6 +154,18 @@ extern void call_rcu1(struct rcu_head *head, RCUCB= Func *func); > }), = \ > (RCUCBFunc *)g_free); > =20 > +typedef char rcu_read_auto_t; Declaring new types ending in _t collides with the namespace reserved by POSIX. While I don't think it will bite us, it's still worth considering if a different name is better. > +static inline void rcu_read_auto_unlock(rcu_read_auto_t *r) > +{ > + rcu_read_unlock(); > +} > + > +G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(rcu_read_auto_t, rcu_read_auto_unlock= ) > + > +#define RCU_READ_LOCK_AUTO g_auto(rcu_read_auto_t) \ > + _rcu_read_auto =3D 'x'; \ I'm a bit lost at where _rcu_read_auto is declared. (I could understand if an earlier macro had created that typedef via concatenating _ with rcu_read_auto_t, but making the preprocessor drop _t is not possible. Is this a typo, and if so, why did the compiler not complain?) > + rcu_read_lock(); > + > #ifdef __cplusplus > } > #endif >=20 --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --e5sPTJgMgEVwCS1SqBvaHOWCF1uM73jYm-- --p71Il7lcb5yFZZddKSgj4mF1gpRtmyIcR Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAl15MaMACgkQp6FrSiUn Q2qvhAf/Ql2ladoOrIk8Oi5qcUes+na3dGmbSPTf6gO2kd9Lbk6up/hj+JP6QUlU WBW5RHcGFNUQP3pghMvg93U2yS6PZRr5SHvOkqoea7pWU/5SWEFNM579UrI508FW Gvgca4bSm3ypNF90HcWMR0Ct+B5WaKmiSS1IG2/2ymYN0Afn7svUmKJ7naIVW92c AgZ+0gc976jZ0cSo3bv+ZMHekamjQrAXnYnUA9CVWzf2pjEI0ELcToWnYtcqRf7J eNtcqL3m2YFDSFTF1yNa2lHTv6amKLFsmFK0OnLYOuXZmiBEfUSkdOTIIM5FoaPu slong0hv4yI13puM10pnyVPkinwOsA== =VHl9 -----END PGP SIGNATURE----- --p71Il7lcb5yFZZddKSgj4mF1gpRtmyIcR--