From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750977AbWGFWju (ORCPT ); Thu, 6 Jul 2006 18:39:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750981AbWGFWjt (ORCPT ); Thu, 6 Jul 2006 18:39:49 -0400 Received: from postel.suug.ch ([194.88.212.233]:41363 "EHLO postel.suug.ch") by vger.kernel.org with ESMTP id S1750976AbWGFWjs (ORCPT ); Thu, 6 Jul 2006 18:39:48 -0400 Date: Fri, 7 Jul 2006 00:40:09 +0200 From: Thomas Graf To: Andrew Morton Cc: nagar@watson.ibm.com, jlan@sgi.com, pj@sgi.com, Valdis.Kletnieks@vt.edu, balbir@in.ibm.com, csturtiv@sgi.com, linux-kernel@vger.kernel.org, hadi@cyberus.ca, netdev@vger.kernel.org Subject: Re: [PATCH] per-task delay accounting taskstats interface: control exit data through cpumasks] Message-ID: <20060706224009.GA14627@postel.suug.ch> References: <44ACD7C3.5040008@watson.ibm.com> <20060706025633.cd4b1c1d.akpm@osdl.org> <1152185865.5986.15.camel@localhost.localdomain> <20060706120835.GY14627@postel.suug.ch> <20060706144808.1dd5fadf.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060706144808.1dd5fadf.akpm@osdl.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Andrew Morton 2006-07-06 14:48 > In the interests of keeping this work decoupled from netlink enhancements > I'd propose the below. Is it bad to modify the data at nla_data()? Yes, it points into a skb data buffer which may be shared by sitting on other queues if the message is to be broadcasted. In this case it would be harmless but the policy is to leave it unmodified. Otherwise I agree it's better to move forward and not wait for the API change. > --- a/kernel/taskstats.c~per-task-delay-accounting-taskstats-interface-control-exit-data-through-cpumasks-fix > +++ a/kernel/taskstats.c > @@ -299,6 +299,23 @@ cleanup: > return 0; > } > > +static int parse(struct nlattr *na, cpumask_t *mask) > +{ > + char *data; > + int len; > + > + if (na == NULL) > + return 1; > + len = nla_len(na); > + if (len > TASKSTATS_CPUMASK_MAXLEN) > + return -E2BIG; > + if (len < 1) > + return -EINVAL; > + data = nla_data(na); > + data[len - 1] = '\0'; > + return cpulist_parse(data, *mask); > +} Usually this is done by using strlcpy: Example fro genetlink.c if (info->attrs[CTRL_ATTR_FAMILY_NAME]) { char name[GENL_NAMSIZ]; if (nla_strlcpy(name, info->attrs[CTRL_ATTR_FAMILY_NAME], GENL_NAMSIZ) >= GENL_NAMSIZ) goto errout; res = genl_family_find_byname(name); }