Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753889AbaJQTTf (ORCPT ); Fri, 17 Oct 2014 15:19:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48466 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753837AbaJQTTe (ORCPT ); Fri, 17 Oct 2014 15:19:34 -0400 Date: Fri, 17 Oct 2014 21:16:22 +0200 From: Oleg Nesterov To: Andrew Morton , Martin Schwidefsky Cc: Tetsuo Handa , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org Subject: [PATCH 1/2] usermodehelper: don't use CLONE_VFORK for ____call_usermodehelper() Message-ID: <20141017191622.GB22270@redhat.com> References: <20141016160042.7f898871@mschwide> <201410170157.AFH86961.FQtFHJVLOFSOOM@I-love.SAKURA.ne.jp> <20141016174209.GB18318@redhat.com> <201410170630.EBH48400.FSOHVQJOFMLtFO@I-love.SAKURA.ne.jp> <20141016215834.GA28864@redhat.com> <20141017093653.6fa60dff@mschwide> <20141017191557.GA22270@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141017191557.GA22270@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After the previous fix CLONE_VFORK in __call_usermodehelper() buys nothing, we rely on on umh_complete() in ____call_usermodehelper() anyway. Remove it. This also eliminates the unnecessary sleep/wakeup in the likely case, and this allows the next change. While at it, kill the "int wait" locals in ____call_usermodehelper() and __call_usermodehelper(), they can safely use sub_info->wait. Signed-off-by: Oleg Nesterov --- kernel/kmod.c | 12 +++--------- 1 files changed, 3 insertions(+), 9 deletions(-) diff --git a/kernel/kmod.c b/kernel/kmod.c index 80f7a6d..4621771 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -223,7 +223,6 @@ static void umh_complete(struct subprocess_info *sub_info) static int ____call_usermodehelper(void *data) { struct subprocess_info *sub_info = data; - int wait = sub_info->wait & ~UMH_KILLABLE; struct cred *new; int retval; @@ -267,7 +266,7 @@ static int ____call_usermodehelper(void *data) out: sub_info->retval = retval; /* wait_for_helper() will call umh_complete if UHM_WAIT_PROC. */ - if (wait != UMH_WAIT_PROC) + if (!(sub_info->wait & UMH_WAIT_PROC)) umh_complete(sub_info); if (!retval) return 0; @@ -323,18 +322,13 @@ static void __call_usermodehelper(struct work_struct *work) { struct subprocess_info *sub_info = container_of(work, struct subprocess_info, work); - int wait = sub_info->wait & ~UMH_KILLABLE; pid_t pid; - /* CLONE_VFORK: wait until the usermode helper has execve'd - * successfully We need the data structures to stay around - * until that is done. */ - if (wait == UMH_WAIT_PROC) + if (sub_info->wait & UMH_WAIT_PROC) pid = kernel_thread(wait_for_helper, sub_info, CLONE_FS | CLONE_FILES | SIGCHLD); else { - pid = kernel_thread(call_helper, sub_info, - CLONE_VFORK | SIGCHLD); + pid = kernel_thread(call_helper, sub_info, SIGCHLD); /* Worker thread stopped blocking khelper thread. */ kmod_thread_locker = NULL; } -- 1.5.5.1 -- 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/