[PATCH 3/3] cgroup: deal with dummp_top in cgroup_name() and cgroup_path()

2014-02-14 Thread Li Zefan 
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 
---
 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 ef0b3af..8c283a9 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)
-- 
1.8.0.2

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[PATCH 3/3] cgroup: deal with dummp_top in cgroup_name() and cgroup_path()

2014-02-14 Thread Li Zefan 
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 lize...@huawei.com
---
 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 ef0b3af..8c283a9 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)
-- 
1.8.0.2

--
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Please read the FAQ at  http://www.tux.org/lkml/