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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 01B96C04AA9 for ; Sat, 4 May 2019 04:10:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1ADA206DF for ; Sat, 4 May 2019 04:10:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726241AbfEDEKs (ORCPT ); Sat, 4 May 2019 00:10:48 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:55786 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725796AbfEDEKs (ORCPT ); Sat, 4 May 2019 00:10:48 -0400 Received: from localhost (unknown [75.104.87.19]) (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 0F1A014D84551; Fri, 3 May 2019 21:10:29 -0700 (PDT) Date: Sat, 04 May 2019 00:10:25 -0400 (EDT) Message-Id: <20190504.001025.1191902881190952783.davem@davemloft.net> To: wenbin.zeng@gmail.com Cc: viro@zeniv.linux.org.uk, bfields@fieldses.org, jlayton@kernel.org, trond.myklebust@hammerspace.com, anna.schumaker@netapp.com, wenbinzeng@tencent.com, dsahern@gmail.com, nicolas.dichtel@6wind.com, willy@infradead.org, edumazet@google.com, jakub.kicinski@netronome.com, tyhicks@canonical.com, chuck.lever@oracle.com, neilb@suse.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH 2/3] netns: add netns_evict into netns_operations From: David Miller In-Reply-To: <1556692945-3996-3-git-send-email-wenbinzeng@tencent.com> References: <1556692945-3996-1-git-send-email-wenbinzeng@tencent.com> <1556692945-3996-3-git-send-email-wenbinzeng@tencent.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Fri, 03 May 2019 21:10:47 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Wenbin Zeng Date: Wed, 1 May 2019 14:42:24 +0800 > The newly added netns_evict() shall be called when the netns inode being > evicted. It provides another path to release netns refcounts, previously > netns_put() is the only choice, but it is not able to release all netns > refcount, for example, a rpc client holds two netns refcounts, these > refcounts are supposed to be released when the rpc client is freed, but > the code to free rpc client is normally triggered by put() callback only > when netns refcount gets to 0, specifically: > refcount=0 -> cleanup_net() -> ops_exit_list -> free rpc client > But netns refcount will never get to 0 before rpc client gets freed, to > break the deadlock, the code to free rpc client can be put into the newly > added netns_evict. > > Signed-off-by: Wenbin Zeng Acked-by: David S. Miller