[PATCH 12/13] cgroup: relocate functions in preparation of kernfs conversion

From: Tejun Heo
Date: Tue Jan 28 2014 - 18:56:16 EST


Relocate cgroup_init/exit_root_id(), cgroup_free_root(),
cgroup_kill_sb() and cgroup_file_name() in preparation of kernfs
conversion.

These are pure relocations to make kernfs conversion easier to follow.

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
---
kernel/cgroup.c | 232 ++++++++++++++++++++++++++++----------------------------
1 file changed, 117 insertions(+), 115 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 0c5d1d1..228ed88 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -170,6 +170,8 @@ static int need_forkexit_callback __read_mostly;
static struct cftype cgroup_base_files[];

static void cgroup_put(struct cgroup *cgrp);
+static int rebind_subsystems(struct cgroupfs_root *root,
+ unsigned long added_mask, unsigned removed_mask);
static void cgroup_destroy_css_killed(struct cgroup *cgrp);
static int cgroup_destroy_locked(struct cgroup *cgrp);
static int cgroup_addrm_files(struct cgroup *cgrp, struct cftype cfts[],
@@ -690,6 +692,42 @@ static struct css_set *find_css_set(struct css_set *old_cset,
return cset;
}

+static int cgroup_init_root_id(struct cgroupfs_root *root, int start, int end)
+{
+ int id;
+
+ lockdep_assert_held(&cgroup_mutex);
+
+ id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, start, end,
+ GFP_KERNEL);
+ if (id < 0)
+ return id;
+
+ root->hierarchy_id = id;
+ return 0;
+}
+
+static void cgroup_exit_root_id(struct cgroupfs_root *root)
+{
+ lockdep_assert_held(&cgroup_mutex);
+
+ if (root->hierarchy_id) {
+ idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
+ root->hierarchy_id = 0;
+ }
+}
+
+static void cgroup_free_root(struct cgroupfs_root *root)
+{
+ if (root) {
+ /* hierarhcy ID shoulid already have been released */
+ WARN_ON_ONCE(root->hierarchy_id);
+
+ idr_destroy(&root->cgroup_idr);
+ kfree(root);
+ }
+}
+
static void cgroup_get_root(struct cgroupfs_root *root)
{
atomic_inc(&root->sb->s_active);
@@ -700,6 +738,59 @@ static void cgroup_put_root(struct cgroupfs_root *root)
deactivate_super(root->sb);
}

+static void cgroup_kill_sb(struct super_block *sb)
+{
+ struct cgroupfs_root *root = sb->s_fs_info;
+ struct cgroup *cgrp = &root->top_cgroup;
+ struct cgrp_cset_link *link, *tmp_link;
+ int ret;
+
+ BUG_ON(!root);
+
+ BUG_ON(root->number_of_cgroups != 1);
+ BUG_ON(!list_empty(&cgrp->children));
+
+ mutex_lock(&cgrp->dentry->d_inode->i_mutex);
+ mutex_lock(&cgroup_tree_mutex);
+ mutex_lock(&cgroup_mutex);
+
+ /* Rebind all subsystems back to the default hierarchy */
+ if (root->flags & CGRP_ROOT_SUBSYS_BOUND) {
+ ret = rebind_subsystems(root, 0, root->subsys_mask);
+ /* Shouldn't be able to fail ... */
+ BUG_ON(ret);
+ }
+
+ /*
+ * Release all the links from cset_links to this hierarchy's
+ * root cgroup
+ */
+ write_lock(&css_set_lock);
+
+ list_for_each_entry_safe(link, tmp_link, &cgrp->cset_links, cset_link) {
+ list_del(&link->cset_link);
+ list_del(&link->cgrp_link);
+ kfree(link);
+ }
+ write_unlock(&css_set_lock);
+
+ if (!list_empty(&root->root_list)) {
+ list_del(&root->root_list);
+ cgroup_root_count--;
+ }
+
+ cgroup_exit_root_id(root);
+
+ mutex_unlock(&cgroup_mutex);
+ mutex_unlock(&cgroup_tree_mutex);
+ mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
+
+ simple_xattrs_free(&cgrp->xattrs);
+
+ kill_litter_super(sb);
+ cgroup_free_root(root);
+}
+
/*
* Return the cgroup for "task" from the given hierarchy. Must be
* called with cgroup_mutex held.
@@ -846,6 +937,32 @@ static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
return buf;
}

+/**
+ * cgroup_file_mode - deduce file mode of a control file
+ * @cft: the control file in question
+ *
+ * returns cft->mode if ->mode is not 0
+ * returns S_IRUGO|S_IWUSR if it has both a read and a write handler
+ * returns S_IRUGO if it has only a read handler
+ * returns S_IWUSR if it has only a write hander
+ */
+static umode_t cgroup_file_mode(const struct cftype *cft)
+{
+ umode_t mode = 0;
+
+ if (cft->mode)
+ return cft->mode;
+
+ if (cft->read_u64 || cft->read_s64 || cft->seq_show)
+ mode |= S_IRUGO;
+
+ if (cft->write_u64 || cft->write_s64 || cft->write_string ||
+ cft->trigger)
+ mode |= S_IWUSR;
+
+ return mode;
+}
+
static void cgroup_free_fn(struct work_struct *work)
{
struct cgroup *cgrp = container_of(work, struct cgroup, destroy_work);
@@ -1356,31 +1473,6 @@ static void init_cgroup_root(struct cgroupfs_root *root)
idr_init(&root->cgroup_idr);
}

-static int cgroup_init_root_id(struct cgroupfs_root *root, int start, int end)
-{
- int id;
-
- lockdep_assert_held(&cgroup_mutex);
-
- id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, start, end,
- GFP_KERNEL);
- if (id < 0)
- return id;
-
- root->hierarchy_id = id;
- return 0;
-}
-
-static void cgroup_exit_root_id(struct cgroupfs_root *root)
-{
- lockdep_assert_held(&cgroup_mutex);
-
- if (root->hierarchy_id) {
- idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
- root->hierarchy_id = 0;
- }
-}
-
static int cgroup_test_super(struct super_block *sb, void *data)
{
struct cgroup_sb_opts *opts = data;
@@ -1430,17 +1522,6 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
return root;
}

-static void cgroup_free_root(struct cgroupfs_root *root)
-{
- if (root) {
- /* hierarhcy ID shoulid already have been released */
- WARN_ON_ONCE(root->hierarchy_id);
-
- idr_destroy(&root->cgroup_idr);
- kfree(root);
- }
-}
-
static int cgroup_set_super(struct super_block *sb, void *data)
{
int ret;
@@ -1682,59 +1763,6 @@ out_unlock:
return ERR_PTR(ret);
}

-static void cgroup_kill_sb(struct super_block *sb)
-{
- struct cgroupfs_root *root = sb->s_fs_info;
- struct cgroup *cgrp = &root->top_cgroup;
- struct cgrp_cset_link *link, *tmp_link;
- int ret;
-
- BUG_ON(!root);
-
- BUG_ON(root->number_of_cgroups != 1);
- BUG_ON(!list_empty(&cgrp->children));
-
- mutex_lock(&cgrp->dentry->d_inode->i_mutex);
- mutex_lock(&cgroup_tree_mutex);
- mutex_lock(&cgroup_mutex);
-
- /* Rebind all subsystems back to the default hierarchy */
- if (root->flags & CGRP_ROOT_SUBSYS_BOUND) {
- ret = rebind_subsystems(root, 0, root->subsys_mask);
- /* Shouldn't be able to fail ... */
- BUG_ON(ret);
- }
-
- /*
- * Release all the links from cset_links to this hierarchy's
- * root cgroup
- */
- write_lock(&css_set_lock);
-
- list_for_each_entry_safe(link, tmp_link, &cgrp->cset_links, cset_link) {
- list_del(&link->cset_link);
- list_del(&link->cgrp_link);
- kfree(link);
- }
- write_unlock(&css_set_lock);
-
- if (!list_empty(&root->root_list)) {
- list_del(&root->root_list);
- cgroup_root_count--;
- }
-
- cgroup_exit_root_id(root);
-
- mutex_unlock(&cgroup_mutex);
- mutex_unlock(&cgroup_tree_mutex);
- mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
-
- simple_xattrs_free(&cgrp->xattrs);
-
- kill_litter_super(sb);
- cgroup_free_root(root);
-}
-
static struct file_system_type cgroup_fs_type = {
.name = "cgroup",
.mount = cgroup_mount,
@@ -2610,32 +2638,6 @@ static int cgroup_create_file(struct dentry *dentry, umode_t mode,
return 0;
}

-/**
- * cgroup_file_mode - deduce file mode of a control file
- * @cft: the control file in question
- *
- * returns cft->mode if ->mode is not 0
- * returns S_IRUGO|S_IWUSR if it has both a read and a write handler
- * returns S_IRUGO if it has only a read handler
- * returns S_IWUSR if it has only a write hander
- */
-static umode_t cgroup_file_mode(const struct cftype *cft)
-{
- umode_t mode = 0;
-
- if (cft->mode)
- return cft->mode;
-
- if (cft->read_u64 || cft->read_s64 || cft->seq_show)
- mode |= S_IRUGO;
-
- if (cft->write_u64 || cft->write_s64 || cft->write_string ||
- cft->trigger)
- mode |= S_IWUSR;
-
- return mode;
-}
-
static int cgroup_add_file(struct cgroup *cgrp, struct cftype *cft)
{
struct dentry *dir = cgrp->dentry;
--
1.8.5.3

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