From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 3/8] cgroup: grab cgroup_mutex earlier in cgroup_subtree_control_write() Date: Tue, 6 May 2014 16:19:29 -0400 Message-ID: <1399407574-21472-4-git-send-email-tj@kernel.org> References: <1399407574-21472-1-git-send-email-tj@kernel.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=RWobBymw4MCF1UEFfvcg36Gk6d2aVpEtbEFubAhxWFk=; b=QMT/QaeUGrYgKxhuz1a1sI58Y7yiOJzgZH3HSzlLTMc36QUTw4anBzScDggRQ+Oe5q vZ15mXR3adDXN9GZvHemyLrtkRzXsJp5u2japvqoSZBBdwY0ZLirTFOOwRqpoyyt9zWl rzE1pIKOawZ/AkB1/XmP5lvDyA5VDigVzLwgyS9vVyIkvsN7CMoQgxrxT/5TOI52uLv6 cM8/eHYuA3EbDejlacc7f3HboDF0SgnuB2mQoM6/+yTBM8FFha8XsHe0J2uet5SEB45h ihZEFMAGJyYPcH8+GREmUNSPROdwi6vd6dx7YbS17oSq9o7e89h5kNpmt1eIcWi/WruH /5YQ== In-Reply-To: <1399407574-21472-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lizefan@huawei.com Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo Move cgroup_lock_live_group() invocation upwards to right below cgroup_tree_mutex in cgroup_subtree_control_write(). This is to help the planned locking simplification. This doesn't make any userland-visible behavioral changes. Signed-off-by: Tejun Heo --- kernel/cgroup.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 69c0ed9..f544e46 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -2583,6 +2583,10 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, kernfs_break_active_protection(of->kn); mutex_lock(&cgroup_tree_mutex); + if (!cgroup_lock_live_group(cgrp)) { + ret = -ENODEV; + goto out_unlock_tree; + } for_each_subsys(ss, ssid) { if (enable & (1 << ssid)) { @@ -2606,6 +2610,7 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, cgroup_get(child); prepare_to_wait(&child->offline_waitq, &wait, TASK_UNINTERRUPTIBLE); + mutex_unlock(&cgroup_mutex); mutex_unlock(&cgroup_tree_mutex); schedule(); finish_wait(&child->offline_waitq, &wait); @@ -2620,7 +2625,7 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, (cgrp->parent && !(cgrp->parent->child_subsys_mask & (1 << ssid)))) { ret = -ENOENT; - goto out_unlock_tree; + goto out_unlock; } } else if (disable & (1 << ssid)) { if (!(cgrp->child_subsys_mask & (1 << ssid))) { @@ -2632,7 +2637,7 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, cgroup_for_each_live_child(child, cgrp) { if (child->child_subsys_mask & (1 << ssid)) { ret = -EBUSY; - goto out_unlock_tree; + goto out_unlock; } } } @@ -2640,12 +2645,7 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, if (!enable && !disable) { ret = 0; - goto out_unlock_tree; - } - - if (!cgroup_lock_live_group(cgrp)) { - ret = -ENODEV; - goto out_unlock_tree; + goto out_unlock; } /* -- 1.9.0