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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT 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 24776C32789 for ; Thu, 8 Nov 2018 06:59:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D94F02086C for ; Thu, 8 Nov 2018 06:59:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D94F02086C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=stgolabs.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 S1726642AbeKHQdx (ORCPT ); Thu, 8 Nov 2018 11:33:53 -0500 Received: from mx2.suse.de ([195.135.220.15]:54350 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726027AbeKHQdx (ORCPT ); Thu, 8 Nov 2018 11:33:53 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 70512ABCE; Thu, 8 Nov 2018 06:59:49 +0000 (UTC) Date: Wed, 7 Nov 2018 22:59:42 -0800 From: Davidlohr Bueso To: "chouryzhou(??????)" Cc: "gregkh@linuxfoundation.org" , "arve@android.com" , "tkjos@android.com" , "akpm@linux-foundation.org" , "devel@driverdev.osuosl.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH V2] binder: ipc namespace support for android binder Message-ID: <20181108065942.6gnb675xb2wuerrl@linux-r8p5> References: <5FBCBE569E134E4CA167B91C0A77FD610198F6BB7D@EXMBX-SZMAIL022.tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <5FBCBE569E134E4CA167B91C0A77FD610198F6BB7D@EXMBX-SZMAIL022.tencent.com> User-Agent: NeoMutt/20180323 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 29 Oct 2018, chouryzhou(??????) wrote: >@@ -63,6 +63,12 @@ struct ipc_namespace { > unsigned int mq_msg_default; > unsigned int mq_msgsize_default; > >+ /* next fields are for binder */ >+ struct mutex binder_procs_lock; >+ struct hlist_head binder_procs; >+ struct mutex binder_contexts_lock; >+ struct hlist_head binder_contexts; I don't think you want a mutex here protecting the binder_contexts list. Afaict there is no concurrency going on: you only modify it in when doing namespace init and exit (for which you have no serialization); do you even need a lock here? Or at least I would think a more lightweight alternative (rcu/spinlock/rwlock) would suffice. Thanks, Davidlohr