move cgroupfs_root to include/linux/cgroup.h

While controllers shouldn't be accessing cgroupfs_root directly, it
being hidden inside kern/cgroup.c makes somethings pretty silly.  This
makes routing hierarchy-wide settings which need to be visible to
controllers cumbersome.

We're gonna add another hierarchy-wide setting which needs to be
accessed from controllers.  Move cgroupfs_root and its flags to the
header file so that we can access root settings with inline helpers.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Li Zefan <lizefan@huawei.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 45aee0fc6b98..b21881e1ea08 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -19,6 +19,7 @@
 #include <linux/idr.h>
 #include <linux/workqueue.h>
 #include <linux/xattr.h>
+#include <linux/fs.h>
 
 #ifdef CONFIG_CGROUPS
 
@@ -238,6 +239,62 @@ struct cgroup {
         struct simple_xattrs xattrs;
 };
 
+#define MAX_CGROUP_ROOT_NAMELEN 64
+
+/* cgroupfs_root->flags */
+enum {
+        CGRP_ROOT_NOPREFIX      = (1 << 1), /* mounted subsystems have no named prefix */
+        CGRP_ROOT_XATTR         = (1 << 2), /* supports extended attributes */
+};
+
+/*
+ * A cgroupfs_root represents the root of a cgroup hierarchy, and may be
+ * associated with a superblock to form an active hierarchy.  This is
+ * internal to cgroup core.  Don't access directly from controllers.
+ */
+struct cgroupfs_root {
+        struct super_block *sb;
+
+        /*
+         * The bitmask of subsystems intended to be attached to this
+         * hierarchy
+         */
+        unsigned long subsys_mask;
+
+        /* Unique id for this hierarchy. */
+        int hierarchy_id;
+
+        /* The bitmask of subsystems currently attached to this hierarchy */
+        unsigned long actual_subsys_mask;
+
+        /* A list running through the attached subsystems */
+        struct list_head subsys_list;
+
+        /* The root cgroup for this hierarchy */
+        struct cgroup top_cgroup;
+
+        /* Tracks how many cgroups are currently defined in hierarchy.*/
+        int number_of_cgroups;
+
+        /* A list running through the active hierarchies */
+        struct list_head root_list;
+
+        /* All cgroups on this root, cgroup_mutex protected */
+        struct list_head allcg_list;
+
+        /* Hierarchy-specific flags */
+        unsigned long flags;
+
+        /* IDs for cgroups in this hierarchy */
+        struct ida cgroup_ida;
+
+        /* The path to use for release notifications. */
+        char release_agent_path[PATH_MAX];
+
+        /* The name for this hierarchy - may be empty */
+        char name[MAX_CGROUP_ROOT_NAMELEN];
+};
+
 /*
  * A css_set is a structure holding pointers to a set of
  * cgroup_subsys_state objects. This saves space in the task struct