From cc045e3952175e84c38dad22dea14465b9fc8fb5 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizefan@huawei.com>
Date: Fri, 14 Feb 2014 16:56:04 +0800
Subject: [PATCH] cgroup: deal with dummp_top in cgroup_name() and
cgroup_path()
My kernel fails to boot, because blkcg calls cgroup_path() while
cgroupfs is not mounted.
Fix both cgroup_name() and cgroup_path().
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
include/linux/cgroup.h | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index ef0b3af0e61c..8c283a910b91 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -487,13 +487,21 @@ struct cgroup_subsys_state *seq_css(struct seq_file *seq);
static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
{
- return kernfs_name(cgrp->kn, buf, buflen);
+ /* dummy_top doesn't have a kn associated */
+ if (cgrp->kn)
+ return kernfs_name(cgrp->kn, buf, buflen);
+ else
+ return strlcpy(buf, "/", buflen);
}
static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf,
size_t buflen)
{
- return kernfs_path(cgrp->kn, buf, buflen);
+ /* dummy_top doesn't have a kn associated */
+ if (cgrp->kn)
+ return kernfs_path(cgrp->kn, buf, buflen);
+ strlcpy(buf, "/", buflen);
+ return (buflen <= 2) ? NULL : buf;
}
static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
--
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