Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756080Ab3H2Xx0 (ORCPT ); Thu, 29 Aug 2013 19:53:26 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:52805 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752998Ab3H2XxY (ORCPT ); Thu, 29 Aug 2013 19:53:24 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Linux Containers Cc: "Serge E. Hallyn" , References: <87ob8gys0d.fsf@xmission.com> Date: Thu, 29 Aug 2013 16:53:16 -0700 In-Reply-To: <87ob8gys0d.fsf@xmission.com> (Eric W. Biederman's message of "Thu, 29 Aug 2013 16:52:18 -0700") Message-ID: <87ioyoyryr.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX1/Uq2QGal2rD09GdCzInIl7AktJ+zuRYD4= X-SA-Exim-Connect-IP: 98.207.154.105 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 1.5 TR_Symld_Words too many words that have symbols inside * 0.7 XMSubLong Long Subject * -0.0 BAYES_20 BODY: Bayes spam probability is 5 to 20% * [score: 0.0553] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject * 0.0 T_TooManySym_02 5+ unique symbols in subject X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: **;Linux Containers X-Spam-Relay-Country: Subject: [REVIEW][PATCH 1/5] namespaces: Simplify copy_namespaces so it is clear what is going on. X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 14 Nov 2012 14:26:46 -0700) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2319 Lines: 83 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" --- 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/