From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: [PATCH 2/2] cgroups: Clean up cgroup_pidlist_find() a bit Date: Tue, 26 Jan 2010 16:17:04 +0800 Message-ID: <4B5EA500.5040802@cn.fujitsu.com> References: <4B5EA4EC.8020700@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B5EA4EC.8020700@cn.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org To: Li Zefan Cc: Andrew Morton , Paul Menage , Ben Blum , LKML , "containers@lists.osdl.org" List-Id: containers.vger.kernel.org Don't Call get_pid_ns() before we locate/alloc the ns. Signed-off-by: Li Zefan --- cgroup.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/kernel/cgroup.c.orig 2010-01-26 14:24:29.000000000 +0800 +++ a/kernel/cgroup.c 2010-01-26 14:24:44.000000000 +0800 @@ -2643,7 +2643,8 @@ static struct cgroup_pidlist *cgroup_pid { struct cgroup_pidlist *l; /* don't need task_nsproxy() if we're looking at ourself */ - struct pid_namespace *ns = get_pid_ns(current->nsproxy->pid_ns); + struct pid_namespace *ns = current->nsproxy->pid_ns; + /* * We can't drop the pidlist_mutex before taking the l->mutex in case * the last ref-holder is trying to remove l from the list at the same @@ -2653,8 +2654,6 @@ static struct cgroup_pidlist *cgroup_pid mutex_lock(&cgrp->pidlist_mutex); list_for_each_entry(l, &cgrp->pidlists, links) { if (l->key.type == type && l->key.ns == ns) { - /* found a matching list - drop the extra refcount */ - put_pid_ns(ns); /* make sure l doesn't vanish out from under us */ down_write(&l->mutex); mutex_unlock(&cgrp->pidlist_mutex); @@ -2665,13 +2664,12 @@ static struct cgroup_pidlist *cgroup_pid l = kmalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL); if (!l) { mutex_unlock(&cgrp->pidlist_mutex); - put_pid_ns(ns); return l; } init_rwsem(&l->mutex); down_write(&l->mutex); l->key.type = type; - l->key.ns = ns; + l->key.ns = get_pid_ns(ns); l->use_count = 0; /* don't increment here */ l->list = NULL; l->owner = cgrp;