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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-23 15:48:35 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-23 15:48:35 -0700
commitc2468d32f5a57298b732826af84cdc39745d179c (patch)
treeadcb5668dbe43a173002f23107e3df8d2a1be396
parent549f3a1218ba18fcde11ef0e22b07e6365645788 (diff)
parent913ffdb54366f94eec65c656cae8c6e00e1ab1b0 (diff)
Merge branch 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup changes from Tejun Heo: "This contains two patches, both of which aren't fixes per-se but I think it'd be better to fast-track them. One removes bcache_subsys_id which was added without proper review through the block tree. Fortunately, bcache cgroup code is unconditionally disabled, so this was never exposed to userland. The cgroup subsys_id is removed. Kent will remove the affected (disabled) code through bcache branch. The other simplifies task_group_path_from_hierarchy(). The function doesn't currently have in-kernel users but there are external code and development going on dependent on the function and making the function available for 3.11 would make things go smoother" * 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: replace task_cgroup_path_from_hierarchy() with task_cgroup_path() cgroup: remove bcache_subsys_id which got added stealthily
-rw-r--r--include/linux/cgroup.h3
-rw-r--r--include/linux/cgroup_subsys.h45
-rw-r--r--kernel/cgroup.c31
3 files changed, 27 insertions, 52 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 297462b9f41..e9ac882868c 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -542,8 +542,7 @@ int cgroup_rm_cftypes(struct cgroup_subsys *ss, struct cftype *cfts);
bool cgroup_is_descendant(struct cgroup *cgrp, struct cgroup *ancestor);
int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen);
-int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
- char *buf, size_t buflen);
+int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen);
int cgroup_task_count(const struct cgroup *cgrp);
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index 6e7ec64b69a..b613ffd402d 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -1,86 +1,55 @@
-/* Add subsystem definitions of the form SUBSYS(<name>) in this
- * file. Surround each one by a line of comment markers so that
- * patches don't collide
+/*
+ * List of cgroup subsystems.
+ *
+ * DO NOT ADD ANY SUBSYSTEM WITHOUT EXPLICIT ACKS FROM CGROUP MAINTAINERS.
*/
-
-/* */
-
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CPUSETS)
SUBSYS(cpuset)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_DEBUG)
SUBSYS(debug)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_SCHED)
SUBSYS(cpu_cgroup)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_CPUACCT)
SUBSYS(cpuacct)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_MEMCG)
SUBSYS(mem_cgroup)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_DEVICE)
SUBSYS(devices)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_FREEZER)
SUBSYS(freezer)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_NET_CLS_CGROUP)
SUBSYS(net_cls)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_BLK_CGROUP)
SUBSYS(blkio)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_PERF)
SUBSYS(perf)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_NETPRIO_CGROUP)
SUBSYS(net_prio)
#endif
-/* */
-
#if IS_SUBSYS_ENABLED(CONFIG_CGROUP_HUGETLB)
SUBSYS(hugetlb)
#endif
-
-/* */
-
-#ifdef CONFIG_CGROUP_BCACHE
-SUBSYS(bcache)
-#endif
-
-/* */
+/*
+ * DO NOT ADD ANY SUBSYSTEM WITHOUT EXPLICIT ACKS FROM CGROUP MAINTAINERS.
+ */
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 0e0b20b8c5d..789ec4683db 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1845,36 +1845,43 @@ out:
EXPORT_SYMBOL_GPL(cgroup_path);
/**
- * task_cgroup_path_from_hierarchy - cgroup path of a task on a hierarchy
+ * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
- * @hierarchy_id: the hierarchy to look up @task's cgroup from
* @buf: the buffer to write the path into
* @buflen: the length of the buffer
*
- * Determine @task's cgroup on the hierarchy specified by @hierarchy_id and
- * copy its path into @buf. This function grabs cgroup_mutex and shouldn't
- * be used inside locks used by cgroup controller callbacks.
+ * Determine @task's cgroup on the first (the one with the lowest non-zero
+ * hierarchy_id) cgroup hierarchy and copy its path into @buf. This
+ * function grabs cgroup_mutex and shouldn't be used inside locks used by
+ * cgroup controller callbacks.
+ *
+ * Returns 0 on success, fails with -%ENAMETOOLONG if @buflen is too short.
*/
-int task_cgroup_path_from_hierarchy(struct task_struct *task, int hierarchy_id,
- char *buf, size_t buflen)
+int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
{
struct cgroupfs_root *root;
- struct cgroup *cgrp = NULL;
- int ret = -ENOENT;
+ struct cgroup *cgrp;
+ int hierarchy_id = 1, ret = 0;
+
+ if (buflen < 2)
+ return -ENAMETOOLONG;
mutex_lock(&cgroup_mutex);
- root = idr_find(&cgroup_hierarchy_idr, hierarchy_id);
+ root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
+
if (root) {
cgrp = task_cgroup_from_root(task, root);
ret = cgroup_path(cgrp, buf, buflen);
+ } else {
+ /* if no hierarchy exists, everyone is in "/" */
+ memcpy(buf, "/", 2);
}
mutex_unlock(&cgroup_mutex);
-
return ret;
}
-EXPORT_SYMBOL_GPL(task_cgroup_path_from_hierarchy);
+EXPORT_SYMBOL_GPL(task_cgroup_path);
/*
* Control Group taskset