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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 26592C6778F for ; Thu, 26 Jul 2018 20:55:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D618320883 for ; Thu, 26 Jul 2018 20:55:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D618320883 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731662AbeGZWNr (ORCPT ); Thu, 26 Jul 2018 18:13:47 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:46676 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730452AbeGZWNr (ORCPT ); Thu, 26 Jul 2018 18:13:47 -0400 Received: from localhost (unknown [172.58.43.154]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 9EFFA108CAEA2; Thu, 26 Jul 2018 13:55:13 -0700 (PDT) Date: Thu, 26 Jul 2018 13:55:12 -0700 (PDT) Message-Id: <20180726.135512.137481791294209800.davem@davemloft.net> To: neilb@suse.com Cc: herbert@gondor.apana.org.au, tgraf@suug.ch, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, eric.dumazet@gmail.com Subject: Re: [PATCH net-next] rhashtable: detect when object movement between tables might have invalidated a lookup From: David Miller In-Reply-To: <876016r9z5.fsf@notabene.neil.brown.name> References: <87fu0kt5m0.fsf@notabene.neil.brown.name> <20180719.051440.931407144963903326.davem@davemloft.net> <876016r9z5.fsf@notabene.neil.brown.name> X-Mailer: Mew version 6.7 on Emacs 26 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-7 Content-Transfer-Encoding: base64 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 26 Jul 2018 13:55:14 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RnJvbTogTmVpbEJyb3duIDxuZWlsYkBzdXNlLmNvbT4NCkRhdGU6IE1vbiwgMjMgSnVsIDIwMTgg MTE6NTY6MTQgKzEwMDANCg0KPiBTb21lIHVzZXJzIG9mIHJoYXNodGFibGVzIG1pZ2h0IG5lZWQg dG8gbW92ZSBhbiBvYmplY3QgZnJvbSBvbmUgdGFibGUNCj4gdG8gYW5vdGhlciAtICB0aGlzIGFw cGVhcnMgdG8gYmUgdGhlIHJlYXNvbiBmb3IgdGhlIGluY29tcGxldGUgdXNhZ2UNCj4gb2YgTlVM TFMgbWFya2Vycy4NCj4gDQo+IFRvIHN1cHBvcnQgdGhlc2UsIHdlIHN0b3JlIGEgdW5pcXVlIE5V TExTX01BUktFUiBhdCB0aGUgZW5kIG9mDQo+IGVhY2ggY2hhaW4sIGFuZCB3aGVuIGEgc2VhcmNo IGZhaWxzIHRvIGZpbmQgYSBtYXRjaCwgd2UgY2hlY2sNCj4gaWYgdGhlIE5VTExTIG1hcmtlciBm b3VuZCB3YXMgdGhlIGV4cGVjdGVkIG9uZS4gIElmIG5vdCwNCj4gdGhlIHNlYXJjaCBpcyByZXBl YXRlZC4NCiAuLi4NCj4gVGhpcyBpcyBhIHNpbXBsaWZpZWQgdmVyc2lvbiBvZiBhIHByZXZpb3Vz IHBhdGNoLg0KPiBJdCBwcm92aWRlcyBOVUxMU19NQVJLRVIgc3VwcG9ydCBvbmx5IGZvciB0aGUg c3BlY2lmaWMgdXNlIGNhc2UNCj4gd2hpY2ggaXMgY3VycmVudGx5IHRob3VnaHQgYmUgdmFsdWFi bGUgdG8gaW4tdHJlZSB1c2Vycw0KPiBvZiByaGFzaHRhYmxlcy4NCg0KTmVpbCwgdGhpcyBkb2Vz bid0IGV2ZW4gY29tcGlsZToNCg0KSW4gZmlsZSBpbmNsdWRlZCBmcm9tIGxpYi9yaGFzaHRhYmxl LmM6Mjg6DQpsaWIvcmhhc2h0YWJsZS5jOiBJbiBmdW5jdGlvbiChcmh0X2J1Y2tldF9uZXN0ZWSi Og0KLi9pbmNsdWRlL2xpbnV4L3JoYXNodGFibGUuaDo3OToyOiBlcnJvcjogaW5pdGlhbGl6ZXIg ZWxlbWVudCBpcyBub3QgY29tcHV0YWJsZSBhdCBsb2FkIHRpbWUNCiAgKCh2b2lkICopTlVMTFNf TUFSS0VSKCgodW5zaWduZWQgbG9uZykgKHB0cikpID4+IDEpKQ0KICBeDQpsaWIvcmhhc2h0YWJs ZS5jOjExNzg6NDM6IG5vdGU6IGluIGV4cGFuc2lvbiBvZiBtYWNybyChUkhUX05VTExTX01BUktF UqINCiAgc3RhdGljIHN0cnVjdCByaGFzaF9oZWFkIF9fcmN1ICpyaG51bGwgPSBSSFRfTlVMTFNf TUFSS0VSKCZyaG51bGwpOw0KICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAg ICAgIF5+fn5+fn5+fn5+fn5+fn4NCm1ha2VbMV06ICoqKiBbc2NyaXB0cy9NYWtlZmlsZS5idWls ZDozMTg6IGxpYi9yaGFzaHRhYmxlLm9dIEVycm9yIDENCm1ha2U6ICoqKiBbTWFrZWZpbGU6MTY1 MzogbGliL3JoYXNodGFibGUub10gRXJyb3IgMg0KDQpJIGltYWdpbmUgeW91IGhhdmUgYSBtaXgg b2Ygb3RoZXIgY2hhbmdlcyBvciB3aGF0ZXZlciBpbiB5b3VyIHRyZWUsIHNvIEknbGwNCmdpdmUg eW91IHRoZSBiZW5lZml0IG9mIHRoZSBkb3VidC4NCg0KQnV0IHRoaXMgaXMgdGhlIHNlY29uZCB0 aW1lIHRoaXMgaGFzIGhhcHBlbmVkIHdpdGggeW91ciByaGFzaHRhYmxlIGNoYW5nZXMsDQpzby4u Lg0K