Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756870Ab3H3QKJ (ORCPT ); Fri, 30 Aug 2013 12:10:09 -0400 Received: from static.92.5.9.176.clients.your-server.de ([176.9.5.92]:43375 "EHLO hallynmail2" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753886Ab3H3QKI (ORCPT ); Fri, 30 Aug 2013 12:10:08 -0400 Date: Fri, 30 Aug 2013 16:10:03 +0000 From: "Serge E. Hallyn" To: "Eric W. Biederman" Cc: Linux Containers , "Serge E. Hallyn" , linux-kernel@vger.kernel.org Subject: Re: [REVIEW][PATCH 1/5] namespaces: Simplify copy_namespaces so it is clear what is going on. Message-ID: <20130830161003.GA18857@mail.hallyn.com> References: <87ob8gys0d.fsf@xmission.com> <87ioyoyryr.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ioyoyryr.fsf@xmission.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2577 Lines: 86 Quoting Eric W. Biederman (ebiederm@xmission.com): > > Remove the test for the impossible case where tsk->nsproxy == NULL. Fork > will never be called with tsk->nsproxy == NULL. > > Only call get_nsproxy when we don't need to generate a new_nsproxy, > and mark the case where we don't generate a new nsproxy as likely. > > Remove the code to drop an unnecessarily acquired nsproxy value. > > Signed-off-by: "Eric W. Biederman" Acked-by: Serge Hallyn > --- > kernel/nsproxy.c | 35 +++++++++++------------------------ > 1 files changed, 11 insertions(+), 24 deletions(-) > > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c > index d9afd2563..a1ed011 100644 > --- a/kernel/nsproxy.c > +++ b/kernel/nsproxy.c > @@ -125,22 +125,16 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) > struct nsproxy *old_ns = tsk->nsproxy; > struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns); > struct nsproxy *new_ns; > - int err = 0; > > - if (!old_ns) > + if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | > + CLONE_NEWPID | CLONE_NEWNET)))) { > + get_nsproxy(old_ns); > return 0; > - > - get_nsproxy(old_ns); > - > - if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | > - CLONE_NEWPID | CLONE_NEWNET))) > - return 0; > - > - if (!ns_capable(user_ns, CAP_SYS_ADMIN)) { > - err = -EPERM; > - goto out; > } > > + if (!ns_capable(user_ns, CAP_SYS_ADMIN)) > + return -EPERM; > + > /* > * CLONE_NEWIPC must detach from the undolist: after switching > * to a new ipc namespace, the semaphore arrays from the old > @@ -149,22 +143,15 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) > * it along with CLONE_NEWIPC. > */ > if ((flags & (CLONE_NEWIPC | CLONE_SYSVSEM)) == > - (CLONE_NEWIPC | CLONE_SYSVSEM)) { > - err = -EINVAL; > - goto out; > - } > + (CLONE_NEWIPC | CLONE_SYSVSEM)) > + return -EINVAL; > > new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs); > - if (IS_ERR(new_ns)) { > - err = PTR_ERR(new_ns); > - goto out; > - } > + if (IS_ERR(new_ns)) > + return PTR_ERR(new_ns); > > tsk->nsproxy = new_ns; > - > -out: > - put_nsproxy(old_ns); > - return err; > + return 0; > } > > void free_nsproxy(struct nsproxy *ns) > -- > 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/