static DECLARE_RWSEM(css_set_rwsem);
#endif
+/*
+ * Protects cgroup_idr and css_idr so that IDs can be released without
+ * grabbing cgroup_mutex.
+ */
+static DEFINE_SPINLOCK(cgroup_idr_lock);
+
/*
* Protects cgroup_subsys->release_agent_path. Modifying it also requires
* cgroup_mutex. Reading requires either cgroup_mutex or this spinlock.
bool is_add);
static void cgroup_pidlist_destroy_all(struct cgroup *cgrp);
+/* IDR wrappers which synchronize using cgroup_idr_lock */
+static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end,
+ gfp_t gfp_mask)
+{
+ int ret;
+
+ idr_preload(gfp_mask);
+ spin_lock_bh(&cgroup_idr_lock);
+ ret = idr_alloc(idr, ptr, start, end, gfp_mask);
+ spin_unlock_bh(&cgroup_idr_lock);
+ idr_preload_end();
+ return ret;
+}
+
+static void *cgroup_idr_replace(struct idr *idr, void *ptr, int id)
+{
+ void *ret;
+
+ spin_lock_bh(&cgroup_idr_lock);
+ ret = idr_replace(idr, ptr, id);
+ spin_unlock_bh(&cgroup_idr_lock);
+ return ret;
+}
+
+static void cgroup_idr_remove(struct idr *idr, int id)
+{
+ spin_lock_bh(&cgroup_idr_lock);
+ idr_remove(idr, id);
+ spin_unlock_bh(&cgroup_idr_lock);
+}
+
/**
* cgroup_css - obtain a cgroup's css for the specified subsystem
* @cgrp: the cgroup of interest
return test_bit(CGRP_DEAD, &cgrp->flags);
}
-struct cgroup_subsys_state *seq_css(struct seq_file *seq)
+struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
{
- struct kernfs_open_file *of = seq->private;
struct cgroup *cgrp = of->kn->parent->priv;
- struct cftype *cft = seq_cft(seq);
+ struct cftype *cft = of_cft(of);
/*
* This is open and unprotected implementation of cgroup_css().
else
return &cgrp->dummy_css;
}
-EXPORT_SYMBOL_GPL(seq_css);
+EXPORT_SYMBOL_GPL(of_css);
/**
* cgroup_is_descendant - test ancestry
* reference-counted, to improve performance when child cgroups
* haven't been created.
*/
-static struct css_set init_css_set = {
+struct css_set init_css_set = {
.refcount = ATOMIC_INIT(1),
.cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links),
.tasks = LIST_HEAD_INIT(init_css_set.tasks),
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)
+ if (cft->write_u64 || cft->write_s64 || cft->write)
mode |= S_IWUSR;
return mode;
if (WARN_ON_ONCE(cgrp->parent && !cgroup_is_dead(cgrp)))
return;
- /*
- * XXX: cgrp->id is only used to look up css's. As cgroup and
- * css's lifetimes will be decoupled, it should be made
- * per-subsystem and moved to css->id so that lookups are
- * successful until the target css is released.
- */
- mutex_lock(&cgroup_mutex);
- idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
- mutex_unlock(&cgroup_mutex);
+ cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
cgrp->id = -1;
call_rcu(&cgrp->rcu_head, cgroup_free_rcu);
lockdep_assert_held(&cgroup_tree_mutex);
lockdep_assert_held(&cgroup_mutex);
- ret = idr_alloc(&root->cgroup_idr, root_cgrp, 0, 1, GFP_KERNEL);
+ ret = cgroup_idr_alloc(&root->cgroup_idr, root_cgrp, 1, 2, GFP_NOWAIT);
if (ret < 0)
goto out;
root_cgrp->id = ret;
/**
* cgroup_task_migrate - move a task from one cgroup to another.
- * @old_cgrp; the cgroup @tsk is being migrated from
+ * @old_cgrp: the cgroup @tsk is being migrated from
* @tsk: the task being migrated
* @new_cset: the new css_set @tsk is being attached to
*
* function to attach either it or all tasks in its threadgroup. Will lock
* cgroup_mutex and threadgroup.
*/
-static int attach_task_by_pid(struct cgroup *cgrp, u64 pid, bool threadgroup)
+static ssize_t __cgroup_procs_write(struct kernfs_open_file *of, char *buf,
+ size_t nbytes, loff_t off, bool threadgroup)
{
struct task_struct *tsk;
const struct cred *cred = current_cred(), *tcred;
+ struct cgroup *cgrp = of_css(of)->cgroup;
+ pid_t pid;
int ret;
+ if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
+ return -EINVAL;
+
if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
put_task_struct(tsk);
out_unlock_cgroup:
mutex_unlock(&cgroup_mutex);
- return ret;
+ return ret ?: nbytes;
}
/**
}
EXPORT_SYMBOL_GPL(cgroup_attach_task_all);
-static int cgroup_tasks_write(struct cgroup_subsys_state *css,
- struct cftype *cft, u64 pid)
+static ssize_t cgroup_tasks_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
{
- return attach_task_by_pid(css->cgroup, pid, false);
+ return __cgroup_procs_write(of, buf, nbytes, off, false);
}
-static int cgroup_procs_write(struct cgroup_subsys_state *css,
- struct cftype *cft, u64 tgid)
+static ssize_t cgroup_procs_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
{
- return attach_task_by_pid(css->cgroup, tgid, true);
+ return __cgroup_procs_write(of, buf, nbytes, off, true);
}
-static int cgroup_release_agent_write(struct cgroup_subsys_state *css,
- struct cftype *cft, char *buffer)
+static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
{
- struct cgroup_root *root = css->cgroup->root;
+ struct cgroup *cgrp = of_css(of)->cgroup;
+ struct cgroup_root *root = cgrp->root;
BUILD_BUG_ON(sizeof(root->release_agent_path) < PATH_MAX);
- if (!cgroup_lock_live_group(css->cgroup))
+ if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
spin_lock(&release_agent_path_lock);
- strlcpy(root->release_agent_path, buffer,
+ strlcpy(root->release_agent_path, strstrip(buf),
sizeof(root->release_agent_path));
spin_unlock(&release_agent_path_lock);
mutex_unlock(&cgroup_mutex);
- return 0;
+ return nbytes;
}
static int cgroup_release_agent_show(struct seq_file *seq, void *v)
{
struct cgroup *cgrp = seq_css(seq)->cgroup;
- if (!cgroup_lock_live_group(cgrp))
- return -ENODEV;
+ spin_lock(&release_agent_path_lock);
seq_puts(seq, cgrp->root->release_agent_path);
+ spin_unlock(&release_agent_path_lock);
seq_putc(seq, '\n');
- mutex_unlock(&cgroup_mutex);
return 0;
}
}
/* change the enabled child controllers for a cgroup in the default hierarchy */
-static int cgroup_subtree_control_write(struct cgroup_subsys_state *dummy_css,
- struct cftype *cft, char *buffer)
+static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes,
+ loff_t off)
{
- unsigned int enable_req = 0, disable_req = 0, enable, disable;
- struct cgroup *cgrp = dummy_css->cgroup, *child;
+ unsigned int enable = 0, disable = 0;
+ struct cgroup *cgrp = of_css(of)->cgroup, *child;
struct cgroup_subsys *ss;
- char *tok, *p;
+ char *tok;
int ssid, ret;
/*
- * Parse input - white space separated list of subsystem names
- * prefixed with either + or -.
+ * Parse input - space separated list of subsystem names prefixed
+ * with either + or -.
*/
- p = buffer;
- while ((tok = strsep(&p, " \t\n"))) {
+ buf = strstrip(buf);
+ while ((tok = strsep(&buf, " "))) {
+ if (tok[0] == '\0')
+ continue;
for_each_subsys(ss, ssid) {
if (ss->disabled || strcmp(tok + 1, ss->name))
continue;
if (*tok == '+') {
- enable_req |= 1 << ssid;
- disable_req &= ~(1 << ssid);
+ enable |= 1 << ssid;
+ disable &= ~(1 << ssid);
} else if (*tok == '-') {
- disable_req |= 1 << ssid;
- enable_req &= ~(1 << ssid);
+ disable |= 1 << ssid;
+ enable &= ~(1 << ssid);
} else {
return -EINVAL;
}
* active_ref protection.
*/
cgroup_get(cgrp);
- kernfs_break_active_protection(cgrp->control_kn);
-retry:
- enable = enable_req;
- disable = disable_req;
+ kernfs_break_active_protection(of->kn);
mutex_lock(&cgroup_tree_mutex);
* cases, wait till it's gone using offline_waitq.
*/
cgroup_for_each_live_child(child, cgrp) {
- wait_queue_t wait;
+ DEFINE_WAIT(wait);
if (!cgroup_css(child, ss))
continue;
+ cgroup_get(child);
prepare_to_wait(&child->offline_waitq, &wait,
TASK_UNINTERRUPTIBLE);
mutex_unlock(&cgroup_tree_mutex);
schedule();
finish_wait(&child->offline_waitq, &wait);
- goto retry;
+ cgroup_put(child);
+
+ ret = restart_syscall();
+ goto out_unbreak;
}
/* unavailable or not enabled on the parent? */
mutex_unlock(&cgroup_mutex);
out_unlock_tree:
mutex_unlock(&cgroup_tree_mutex);
- kernfs_unbreak_active_protection(cgrp->control_kn);
+out_unbreak:
+ kernfs_unbreak_active_protection(of->kn);
cgroup_put(cgrp);
- return ret;
+ return ret ?: nbytes;
err_undo_css:
cgrp->child_subsys_mask &= ~enable;
struct cgroup_subsys_state *css;
int ret;
+ if (cft->write)
+ return cft->write(of, buf, nbytes, off);
+
/*
* kernfs guarantees that a file isn't deleted with operations in
* flight, which means that the matching css is and stays alive and
css = cgroup_css(cgrp, cft->ss);
rcu_read_unlock();
- if (cft->write_string) {
- ret = cft->write_string(css, cft, strstrip(buf));
- } else if (cft->write_u64) {
+ if (cft->write_u64) {
unsigned long long v;
ret = kstrtoull(buf, 0, &v);
if (!ret)
ret = kstrtoll(buf, 0, &v);
if (!ret)
ret = cft->write_s64(css, cft, v);
- } else if (cft->trigger) {
- ret = cft->trigger(css, (unsigned int)cft->private);
} else {
ret = -EINVAL;
}
return ret;
}
- if (cft->seq_show == cgroup_subtree_control_show)
- cgrp->control_kn = kn;
- else if (cft->seq_show == cgroup_populated_show)
+ if (cft->seq_show == cgroup_populated_show)
cgrp->populated_kn = kn;
return 0;
}
/*
* We aren't being called from kernfs and there's no guarantee on
- * @kn->priv's validity. For this and css_tryget_from_dir(),
+ * @kn->priv's validity. For this and css_tryget_online_from_dir(),
* @kn->priv is RCU safe. Let's do the RCU dancing.
*/
rcu_read_lock();
.seq_stop = cgroup_pidlist_stop,
.seq_show = cgroup_pidlist_show,
.private = CGROUP_FILE_PROCS,
- .write_u64 = cgroup_procs_write,
+ .write = cgroup_procs_write,
.mode = S_IRUGO | S_IWUSR,
},
{
.name = "cgroup.subtree_control",
.flags = CFTYPE_ONLY_ON_DFL,
.seq_show = cgroup_subtree_control_show,
- .write_string = cgroup_subtree_control_write,
+ .write = cgroup_subtree_control_write,
},
{
.name = "cgroup.populated",
.seq_stop = cgroup_pidlist_stop,
.seq_show = cgroup_pidlist_show,
.private = CGROUP_FILE_TASKS,
- .write_u64 = cgroup_tasks_write,
+ .write = cgroup_tasks_write,
.mode = S_IRUGO | S_IWUSR,
},
{
.name = "release_agent",
.flags = CFTYPE_INSANE | CFTYPE_ONLY_ON_ROOT,
.seq_show = cgroup_release_agent_show,
- .write_string = cgroup_release_agent_write,
+ .write = cgroup_release_agent_write,
.max_write_len = PATH_MAX - 1,
},
{ } /* terminate */
* Implemented in kill_css().
*
* 2. When the percpu_ref is confirmed to be visible as killed on all CPUs
- * and thus css_tryget() is guaranteed to fail, the css can be offlined
- * by invoking offline_css(). After offlining, the base ref is put.
- * Implemented in css_killed_work_fn().
+ * and thus css_tryget_online() is guaranteed to fail, the css can be
+ * offlined by invoking offline_css(). After offlining, the base ref is
+ * put. Implemented in css_killed_work_fn().
*
* 3. When the percpu_ref reaches zero, the only possible remaining
* accessors are inside RCU read sections. css_release() schedules the
{
struct cgroup_subsys_state *css =
container_of(ref, struct cgroup_subsys_state, refcnt);
+ struct cgroup_subsys *ss = css->ss;
+
+ cgroup_idr_remove(&ss->css_idr, css->id);
- RCU_INIT_POINTER(css->cgroup->subsys[css->ss->id], NULL);
call_rcu(&css->rcu_head, css_free_rcu_fn);
}
-static void init_css(struct cgroup_subsys_state *css, struct cgroup_subsys *ss,
- struct cgroup *cgrp)
+static void init_and_link_css(struct cgroup_subsys_state *css,
+ struct cgroup_subsys *ss, struct cgroup *cgrp)
{
+ cgroup_get(cgrp);
+
css->cgroup = cgrp;
css->ss = ss;
css->flags = 0;
- if (cgrp->parent)
+ if (cgrp->parent) {
css->parent = cgroup_css(cgrp->parent, ss);
- else
+ css_get(css->parent);
+ } else {
css->flags |= CSS_ROOT;
+ }
BUG_ON(cgroup_css(cgrp, ss));
}
if (IS_ERR(css))
return PTR_ERR(css);
+ init_and_link_css(css, ss, cgrp);
+
err = percpu_ref_init(&css->refcnt, css_release);
if (err)
goto err_free_css;
- init_css(css, ss, cgrp);
+ err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_NOWAIT);
+ if (err < 0)
+ goto err_free_percpu_ref;
+ css->id = err;
err = cgroup_populate_dir(cgrp, 1 << ss->id);
if (err)
- goto err_free_percpu_ref;
+ goto err_free_id;
+
+ /* @css is ready to be brought online now, make it visible */
+ cgroup_idr_replace(&ss->css_idr, css, css->id);
err = online_css(css);
if (err)
goto err_clear_dir;
- cgroup_get(cgrp);
- css_get(css->parent);
-
if (ss->broken_hierarchy && !ss->warned_broken_hierarchy &&
parent->parent) {
pr_warn("%s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n",
err_clear_dir:
cgroup_clear_dir(css->cgroup, 1 << css->ss->id);
+err_free_id:
+ cgroup_idr_remove(&ss->css_idr, css->id);
err_free_percpu_ref:
percpu_ref_cancel_init(&css->refcnt);
err_free_css:
- ss->css_free(css);
+ call_rcu(&css->rcu_head, css_free_rcu_fn);
return err;
}
{
struct cgroup *cgrp;
struct cgroup_root *root = parent->root;
- int ssid, err;
+ int ssid, ret;
struct cgroup_subsys *ss;
struct kernfs_node *kn;
- /* allocate the cgroup and its ID, 0 is reserved for the root */
- cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);
- if (!cgrp)
- return -ENOMEM;
-
mutex_lock(&cgroup_tree_mutex);
/*
* don't get nasty surprises if we ever grow another caller.
*/
if (!cgroup_lock_live_group(parent)) {
- err = -ENODEV;
- goto err_unlock_tree;
+ ret = -ENODEV;
+ goto out_unlock_tree;
+ }
+
+ /* allocate the cgroup and its ID, 0 is reserved for the root */
+ cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);
+ if (!cgrp) {
+ ret = -ENOMEM;
+ goto out_unlock;
}
/*
* Temporarily set the pointer to NULL, so idr_find() won't return
* a half-baked cgroup.
*/
- cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 1, 0, GFP_KERNEL);
+ cgrp->id = cgroup_idr_alloc(&root->cgroup_idr, NULL, 2, 0, GFP_NOWAIT);
if (cgrp->id < 0) {
- err = -ENOMEM;
- goto err_unlock;
+ ret = -ENOMEM;
+ goto out_free_cgrp;
}
init_cgroup_housekeeping(cgrp);
cgrp->parent = parent;
cgrp->dummy_css.parent = &parent->dummy_css;
- cgrp->root = parent->root;
+ cgrp->root = root;
if (notify_on_release(parent))
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
/* create the directory */
kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
if (IS_ERR(kn)) {
- err = PTR_ERR(kn);
- goto err_free_id;
+ ret = PTR_ERR(kn);
+ goto out_free_id;
}
cgrp->kn = kn;
* @cgrp is now fully operational. If something fails after this
* point, it'll be released via the normal destruction path.
*/
- idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
+ cgroup_idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
- err = cgroup_kn_set_ugid(kn);
- if (err)
- goto err_destroy;
+ ret = cgroup_kn_set_ugid(kn);
+ if (ret)
+ goto out_destroy;
- err = cgroup_addrm_files(cgrp, cgroup_base_files, true);
- if (err)
- goto err_destroy;
+ ret = cgroup_addrm_files(cgrp, cgroup_base_files, true);
+ if (ret)
+ goto out_destroy;
/* let's create and online css's */
for_each_subsys(ss, ssid) {
if (parent->child_subsys_mask & (1 << ssid)) {
- err = create_css(cgrp, ss);
- if (err)
- goto err_destroy;
+ ret = create_css(cgrp, ss);
+ if (ret)
+ goto out_destroy;
}
}
kernfs_activate(kn);
- mutex_unlock(&cgroup_mutex);
- mutex_unlock(&cgroup_tree_mutex);
-
- return 0;
+ ret = 0;
+ goto out_unlock;
-err_free_id:
- idr_remove(&root->cgroup_idr, cgrp->id);
-err_unlock:
+out_free_id:
+ cgroup_idr_remove(&root->cgroup_idr, cgrp->id);
+out_free_cgrp:
+ kfree(cgrp);
+out_unlock:
mutex_unlock(&cgroup_mutex);
-err_unlock_tree:
+out_unlock_tree:
mutex_unlock(&cgroup_tree_mutex);
- kfree(cgrp);
- return err;
+ return ret;
-err_destroy:
+out_destroy:
cgroup_destroy_locked(cgrp);
- mutex_unlock(&cgroup_mutex);
- mutex_unlock(&cgroup_tree_mutex);
- return err;
+ goto out_unlock;
}
static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
/*
* This is called when the refcnt of a css is confirmed to be killed.
- * css_tryget() is now guaranteed to fail.
+ * css_tryget_online() is now guaranteed to fail.
*/
static void css_killed_work_fn(struct work_struct *work)
{
mutex_lock(&cgroup_mutex);
/*
- * css_tryget() is guaranteed to fail now. Tell subsystems to
- * initate destruction.
+ * css_tryget_online() is guaranteed to fail now. Tell subsystems
+ * to initate destruction.
*/
offline_css(css);
*
* This function initiates destruction of @css by removing cgroup interface
* files and putting its base reference. ->css_offline() will be invoked
- * asynchronously once css_tryget() is guaranteed to fail and when the
- * reference count reaches zero, @css will be released.
+ * asynchronously once css_tryget_online() is guaranteed to fail and when
+ * the reference count reaches zero, @css will be released.
*/
static void kill_css(struct cgroup_subsys_state *css)
{
/*
* cgroup core guarantees that, by the time ->css_offline() is
* invoked, no new css reference will be given out via
- * css_tryget(). We can't simply call percpu_ref_kill() and
+ * css_tryget_online(). We can't simply call percpu_ref_kill() and
* proceed to offlining css's because percpu_ref_kill() doesn't
* guarantee that the ref is seen as killed on all CPUs on return.
*
*
* css's make use of percpu refcnts whose killing latency shouldn't be
* exposed to userland and are RCU protected. Also, cgroup core needs to
- * guarantee that css_tryget() won't succeed by the time ->css_offline() is
- * invoked. To satisfy all the requirements, destruction is implemented in
- * the following two steps.
+ * guarantee that css_tryget_online() won't succeed by the time
+ * ->css_offline() is invoked. To satisfy all the requirements,
+ * destruction is implemented in the following two steps.
*
* s1. Verify @cgrp can be destroyed and mark it dying. Remove all
* userland visible parts and start killing the percpu refcnts of
/*
* There are two control paths which try to determine cgroup from
* dentry without going through kernfs - cgroupstats_build() and
- * css_tryget_from_dir(). Those are supported by RCU protecting
- * clearing of cgrp->kn->priv backpointer, which should happen
- * after all files under it have been removed.
+ * css_tryget_online_from_dir(). Those are supported by RCU
+ * protecting clearing of cgrp->kn->priv backpointer, which should
+ * happen after all files under it have been removed.
*/
kernfs_remove(cgrp->kn); /* @cgrp has an extra ref on its kn */
RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv, NULL);
/**
* cgroup_destroy_css_killed - the second step of cgroup destruction
- * @work: cgroup->destroy_free_work
+ * @cgrp: the cgroup whose csses have just finished offlining
*
* This function is invoked from a work item for a cgroup which is being
* destroyed after all css's are offlined and performs the rest of
.rename = cgroup_rename,
};
-static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
+static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
{
struct cgroup_subsys_state *css;
mutex_lock(&cgroup_tree_mutex);
mutex_lock(&cgroup_mutex);
+ idr_init(&ss->css_idr);
INIT_LIST_HEAD(&ss->cfts);
/* Create the root cgroup state for this subsystem */
css = ss->css_alloc(cgroup_css(&cgrp_dfl_root.cgrp, ss));
/* We don't handle early failures gracefully */
BUG_ON(IS_ERR(css));
- init_css(css, ss, &cgrp_dfl_root.cgrp);
+ init_and_link_css(css, ss, &cgrp_dfl_root.cgrp);
+ if (early) {
+ /* idr_alloc() can't be called safely during early init */
+ css->id = 1;
+ } else {
+ css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, GFP_KERNEL);
+ BUG_ON(css->id < 0);
+ }
/* Update the init_css_set to contain a subsys
* pointer to this state - since the subsystem is
ss->name = cgroup_subsys_name[i];
if (ss->early_init)
- cgroup_init_subsys(ss);
+ cgroup_init_subsys(ss, true);
}
return 0;
}
mutex_unlock(&cgroup_tree_mutex);
for_each_subsys(ss, ssid) {
- if (!ss->early_init)
- cgroup_init_subsys(ss);
+ if (ss->early_init) {
+ struct cgroup_subsys_state *css =
+ init_css_set.subsys[ss->id];
+
+ css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2,
+ GFP_KERNEL);
+ BUG_ON(css->id < 0);
+ } else {
+ cgroup_init_subsys(ss, false);
+ }
list_add_tail(&init_css_set.e_cset_node[ssid],
&cgrp_dfl_root.cgrp.e_csets[ssid]);
__setup("cgroup_disable=", cgroup_disable);
/**
- * css_tryget_from_dir - get corresponding css from the dentry of a cgroup dir
+ * css_tryget_online_from_dir - get corresponding css from a cgroup dentry
* @dentry: directory dentry of interest
* @ss: subsystem of interest
*
* to get the corresponding css and return it. If such css doesn't exist
* or can't be pinned, an ERR_PTR value is returned.
*/
-struct cgroup_subsys_state *css_tryget_from_dir(struct dentry *dentry,
- struct cgroup_subsys *ss)
+struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
+ struct cgroup_subsys *ss)
{
struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
struct cgroup_subsys_state *css = NULL;
if (cgrp)
css = cgroup_css(cgrp, ss);
- if (!css || !css_tryget(css))
+ if (!css || !css_tryget_online(css))
css = ERR_PTR(-ENOENT);
rcu_read_unlock();
*/
struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
{
- struct cgroup *cgrp;
-
- cgroup_assert_mutexes_or_rcu_locked();
-
- cgrp = idr_find(&ss->root->cgroup_idr, id);
- if (cgrp)
- return cgroup_css(cgrp, ss);
- return NULL;
+ WARN_ON_ONCE(!rcu_read_lock_held());
+ return idr_find(&ss->css_idr, id);
}
#ifdef CONFIG_CGROUP_DEBUG
projects / deliverable / linux.git / blobdiff