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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E6111C433EF for ; Fri, 14 Jan 2022 15:50:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242656AbiANPu4 convert rfc822-to-8bit (ORCPT ); Fri, 14 Jan 2022 10:50:56 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:31915 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235921AbiANPuz (ORCPT ); Fri, 14 Jan 2022 10:50:55 -0500 Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-253-GIvS9ALiNESe27UbGfp3lA-1; Fri, 14 Jan 2022 15:50:53 +0000 X-MC-Unique: GIvS9ALiNESe27UbGfp3lA-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.26; Fri, 14 Jan 2022 15:50:53 +0000 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.026; Fri, 14 Jan 2022 15:50:53 +0000 From: David Laight To: 'Eric Dumazet' , "David S . Miller" , Jakub Kicinski CC: netdev , Eric Dumazet , syzbot , Ido Schimmel , "Jiri Pirko" Subject: RE: [PATCH net] ipv4: make fib_info_cnt atomic Thread-Topic: [PATCH net] ipv4: make fib_info_cnt atomic Thread-Index: AQHYCVzfksLEUKQs60+YleAr3D+cVKxiqY3A Date: Fri, 14 Jan 2022 15:50:52 +0000 Message-ID: <2f8ea7358c17449682f7e72eaed1ce54@AcuMS.aculab.com> References: <20220114153902.1989393-1-eric.dumazet@gmail.com> In-Reply-To: <20220114153902.1989393-1-eric.dumazet@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 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet > Sent: 14 January 2022 15:39 > > Instead of making sure all free_fib_info() callers > hold rtnl, it seems better to convert fib_info_cnt > to an atomic_t. Since fib_info_cnt is only used to control the size of the hash table could it be incremented when a fid is added to the hash table and decremented when it is removed. This is all inside the fib_info_lock. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)