Received: by 2002:a05:6358:7058:b0:131:369:b2a3 with SMTP id 24csp10780923rwp; Fri, 21 Jul 2023 05:03:52 -0700 (PDT) X-Google-Smtp-Source: APBJJlE4K7342G1DP8S6zAKeNnPe8KQPCf0pn4fY6vjjTM53DXeDIKMYJMjHArUkT23mkLh64ULx X-Received: by 2002:a17:907:2cf6:b0:99b:5c3c:3e61 with SMTP id hz22-20020a1709072cf600b0099b5c3c3e61mr1570106ejc.1.1689941032620; Fri, 21 Jul 2023 05:03:52 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1689941032; cv=none; d=google.com; s=arc-20160816; b=NVvZpQvL397AU+DlDBpOiB6A4o0JRvNh5hACPSQehvgQyfsVnLdcSfXxfNDmMt0O/D gJksD5F23kqJ3/ni0UW2WJszzuk1TQoT4t8ODsksQS9+rTrBenDkI8Fp9idiHdMNfdX4 A/9eqeJ+tYShchELDLkZn2UEew8f4coEb9XY8Bku1vlN3DCJdkgQFd8w85XzW62lFoSr CzarHzDLoT648QyxgU93Ok8TrBTKuTDV1EKIFEtLpS0VEhaPfotMWmrPPM/xKD7TWD4e 7qZD0RapUxuzJaDBP/m0ivwInf9laX8/HJVvQmROKW2vy66Qc8ld/vqrZPhOofguBRj5 eWAw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:content-language :mime-version:accept-language:in-reply-to:references:message-id:date :thread-index:thread-topic:subject:cc:to:from; bh=JEzqx26tJBfcnEwuBFkhZdMfwqmDZYZ8GS6IM8l4soA=; fh=wViNJC9HGpe5hqMHw6nW7NYsT9l9kIuvPpxHDkKfxkE=; b=QLNel4vI61t9Eqh9zXoxHMJ1JdvHRVI+hXHt2Ntg4SOPWMJcVPXPGKIzna2vZ/d0xz M9r22YvQjC+PL/aFB5E9doIyTcNvF40C5aHbfwxWkZXMf1/0KReMo/zwB4VFztxbWCy5 V5esb9x981YTIY4evuDL3E+/82ZGE+tmqVL0z2Q6Cmhocccn7QKqTyAyxiWpDS7vpy4a Z2w6KIm0H/xDs2NTyvNy++c+T7K5jOi/Y8UxrQYp7VrtSftF7w2oD7Q+9Gmj3HAhGVFL ncKuhGaP1eM5r3q9+IMFEHio6ZRwRKPPdiDPQdZBdTJkiaUcNvTpO2y4hVLLe2oXjgZ2 nnag== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=aculab.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id q21-20020a170906361500b00992a0966793si2048806ejb.814.2023.07.21.05.03.17; Fri, 21 Jul 2023 05:03:52 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=aculab.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230049AbjGULvr (ORCPT + 99 others); Fri, 21 Jul 2023 07:51:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230224AbjGULvq (ORCPT ); Fri, 21 Jul 2023 07:51:46 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.85.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 707982D7F for ; Fri, 21 Jul 2023 04:51:43 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-148-z_DqXMMUPVCfSx5Bf5_Iew-1; Fri, 21 Jul 2023 12:51:40 +0100 X-MC-Unique: z_DqXMMUPVCfSx5Bf5_Iew-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Fri, 21 Jul 2023 12:51:39 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Fri, 21 Jul 2023 12:51:39 +0100 From: David Laight To: 'Alan Huang' , "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" , "rcu@vger.kernel.org" CC: "Paul E. McKenney" , Eric Dumazet , "roman.gushchin@linux.dev" Subject: RE: Question about the barrier() in hlist_nulls_for_each_entry_rcu() Thread-Topic: Question about the barrier() in hlist_nulls_for_each_entry_rcu() Thread-Index: AQHZuzuWW9UBwZmf30GL9p6MGC4yBq/EGshg Date: Fri, 21 Jul 2023 11:51:39 +0000 Message-ID: References: <04C1E631-725C-47AD-9914-25D5CE04DFF4@gmail.com> In-Reply-To: <04C1E631-725C-47AD-9914-25D5CE04DFF4@gmail.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RnJvbTogQWxhbiBIdWFuZw0KPiBTZW50OiAyMCBKdWx5IDIwMjMgMTk6NTQNCj4gDQo+IEkgbm90 aWNlZCBhIGNvbW1pdCBjODdhMTI0YTVkNWUo4oCcbmV0OiBmb3JjZSBhIHJlbG9hZCBvZiBmaXJz dCBpdGVtIGluIGhsaXN0X251bGxzX2Zvcl9lYWNoX2VudHJ5X3JjdeKAnSkNCj4gYW5kIGEgcmVs YXRlZCBkaXNjdXNzaW9uIFsxXS4NCg0KSG1tbS4uLiB0aGF0IHdhcyBhbGwgYWJvdXQgdGhlIHJl dHJ5IGxvb3AgaW4gaXB2NC91ZHAuYw0KDQpBRkFJQ1QgdGhhdCByZXRyeSBnb3QgZGVsZXRlZCBi eSBjYTA2NWQwYy4NCg0KVGhhdCBhbHNvIGNoYW5nZXMgdGhlIGxpc3QgZnJvbSBobGlzdF9udWxs c194eHggdG8gaGxpc3RfeHh4Lg0KKEknbSBub3Qgc3VyZSBvZiB0aGUgZGlmZmVyZW5jZSkNCg0K VGhpcyBtaWdodCBiZSB3aHkgd2UncmUgc2VlaW5nIHVuZXhwZWN0ZWQgJ3BvcnQgdW5yZWFjaGFi bGUnIG1lc3NhZ2VzPw0KDQpRdWl0ZSB3aHkgdGhhdCBoYXMganVzdCBzdGFydGVkIGhhcHBlbmlu ZyBpcyBhbm90aGVyIGlzc3VlLg0KTW9zdCBvZiB0aGUgVURQIHNvY2tldHMgd2UgY3JlYXRlIGFy ZW4ndCAnY29ubmVjdGVkJyBzbyBJIGRvbid0DQpiZWxpZXZlIHRoZXkgZ2V0IG1vdmVkIGJldHdl ZW4gaGFzaCBjaGFpbnMgLSBqdXN0IGRlbGV0ZWQuDQpUaGUgZGVsZXRpb24gc2hvdWxkIGxlYXZl IHRoZSBoYXNoIGNoYWluIGludGFjdC4NCg0KCURhdmlkDQoNCi0NClJlZ2lzdGVyZWQgQWRkcmVz cyBMYWtlc2lkZSwgQnJhbWxleSBSb2FkLCBNb3VudCBGYXJtLCBNaWx0b24gS2V5bmVzLCBNSzEg MVBULCBVSw0KUmVnaXN0cmF0aW9uIE5vOiAxMzk3Mzg2IChXYWxlcykNCg==