diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 1039fb9ff5f5f998628884dedab422c9b405a36c..9f5bce33e6fe4b6b9f5eda880b30e0826b2a75ee 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -185,7 +185,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
lockdep_assert_held(q->queue_lock);
/* blkg holds a reference to blkcg */
- if (!css_tryget(&blkcg->css)) {
+ if (!css_tryget_online(&blkcg->css)) {
ret = -EINVAL;
goto err_free_blkg;
}
diff --git a/fs/bio.c b/fs/bio.c
index 6f0362b77806c61909aa37433a9e77eb77476cff..0608ef9422bdc6fba65e751defdf09e8980e4e9c 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1970,7 +1970,7 @@ int bio_associate_current(struct bio *bio)
/* associate blkcg if exists */
rcu_read_lock();
css = task_css(current, blkio_cgrp_id);
- if (css && css_tryget(css))
+ if (css && css_tryget_online(css))
bio->bi_css = css;
rcu_read_unlock();
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index bde44618d8c2bd2a28bce7aa1cd5383f744563b9..c5f3684ef557201cb242eeea44406ad45827650c 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -95,16 +95,16 @@ static inline void css_get(struct cgroup_subsys_state *css)
}
/**
- * css_tryget - try to obtain a reference on the specified css
+ * css_tryget_online - try to obtain a reference on the specified css if online
* @css: target css
*
- * Obtain a reference on @css if it's alive. The caller naturally needs to
- * ensure that @css is accessible but doesn't have to be holding a
+ * Obtain a reference on @css if it's online. The caller naturally needs
+ * to ensure that @css is accessible but doesn't have to be holding a
* reference on it - IOW, RCU protected access is good enough for this
* function. Returns %true if a reference count was successfully obtained;
* %false otherwise.
*/
-static inline bool css_tryget(struct cgroup_subsys_state *css)
+static inline bool css_tryget_online(struct cgroup_subsys_state *css)
{
if (css->flags & CSS_ROOT)
return true;
@@ -115,7 +115,7 @@ static inline bool css_tryget(struct cgroup_subsys_state *css)
* css_put - put a css reference
* @css: target css
*
- * Put a reference obtained via css_get() and css_tryget().
+ * Put a reference obtained via css_get() and css_tryget_online().
*/
static inline void css_put(struct cgroup_subsys_state *css)
{
@@ -905,8 +905,8 @@ void css_task_iter_end(struct css_task_iter *it);
int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);
int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
-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);
#else /* !CONFIG_CGROUPS */
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 7633703e9baf324e750412612fcb6f4bb70c2083..671d8a6dae37e011ea812ee6a6304c1bd633161e 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3771,7 +3771,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry)
/*
* 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();
@@ -4060,9 +4060,9 @@ err:
* 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
@@ -4386,7 +4386,7 @@ 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)
{
@@ -4398,8 +4398,8 @@ 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);
@@ -4440,8 +4440,8 @@ static void css_killed_ref_fn(struct percpu_ref *ref)
*
* 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)
{
@@ -4462,7 +4462,7 @@ 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.
*
@@ -4478,9 +4478,9 @@ static void kill_css(struct cgroup_subsys_state *css)
*
* 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
@@ -4574,9 +4574,9 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
/*
* 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);
@@ -5173,7 +5173,7 @@ static int __init cgroup_disable(char *str)
__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
*
@@ -5181,8 +5181,8 @@ __setup("cgroup_disable=", cgroup_disable);
* 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;
@@ -5204,7 +5204,7 @@ struct cgroup_subsys_state *css_tryget_from_dir(struct dentry *dentry,
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();
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 345628c78b5b3779460038ec6f036f9e8b7c1a32..0398f7e9ac8174e38a382b13f2f66907a2b48a28 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -304,7 +304,7 @@ static int freezer_read(struct seq_file *m, void *v)
/* update states bottom-up */
css_for_each_descendant_post(pos, css) {
- if (!css_tryget(pos))
+ if (!css_tryget_online(pos))
continue;
rcu_read_unlock();
@@ -404,7 +404,7 @@ static void freezer_change_state(struct freezer *freezer, bool freeze)
struct freezer *pos_f = css_freezer(pos);
struct freezer *parent = parent_freezer(pos_f);
- if (!css_tryget(pos))
+ if (!css_tryget_online(pos))
continue;
rcu_read_unlock();
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 7c0e8da59e26df228a32faed289c0f4dcf26b083..37ca0a5c226d23b48325a6cb950c5231038a1a26 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -872,7 +872,7 @@ static void update_tasks_cpumask_hier(struct cpuset *root_cs, bool update_root)
continue;
}
}
- if (!css_tryget(&cp->css))
+ if (!css_tryget_online(&cp->css))
continue;
rcu_read_unlock();
@@ -1108,7 +1108,7 @@ static void update_tasks_nodemask_hier(struct cpuset *root_cs, bool update_root)
continue;
}
}
- if (!css_tryget(&cp->css))
+ if (!css_tryget_online(&cp->css))
continue;
rcu_read_unlock();
@@ -2153,7 +2153,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
rcu_read_lock();
cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
- if (cs == &top_cpuset || !css_tryget(&cs->css))
+ if (cs == &top_cpuset || !css_tryget_online(&cs->css))
continue;
rcu_read_unlock();
diff --git a/kernel/events/core.c b/kernel/events/core.c
index f83a71a3e46d75547e540ed317f99531838f408b..077968d19b8a4b71ad8f83c4843016875af4b172 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -607,7 +607,8 @@ static inline int perf_cgroup_connect(int fd, struct perf_event *event,
if (!f.file)
return -EBADF;
- css = css_tryget_from_dir(f.file->f_dentry, &perf_event_cgrp_subsys);
+ css = css_tryget_online_from_dir(f.file->f_dentry,
+ &perf_event_cgrp_subsys);
if (IS_ERR(css)) {
ret = PTR_ERR(css);
goto out;
diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
index 595d7fd795e168e1c38205f2a4d5703f49068399..372f1adca4919603a0b423027a5968c7db4edd7b 100644
--- a/mm/hugetlb_cgroup.c
+++ b/mm/hugetlb_cgroup.c
@@ -181,7 +181,7 @@ int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
again:
rcu_read_lock();
h_cg = hugetlb_cgroup_from_task(current);
- if (!css_tryget(&h_cg->css)) {
+ if (!css_tryget_online(&h_cg->css)) {
rcu_read_unlock();
goto again;
}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c3f82f69ef58f90621caeed859be501f44485b45..5cf3246314a2c74c3664ebee2e7b080558eaaecd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -567,7 +567,8 @@ void sock_update_memcg(struct sock *sk)
memcg = mem_cgroup_from_task(current);
cg_proto = sk->sk_prot->proto_cgroup(memcg);
if (!mem_cgroup_is_root(memcg) &&
- memcg_proto_active(cg_proto) && css_tryget(&memcg->css)) {
+ memcg_proto_active(cg_proto) &&
+ css_tryget_online(&memcg->css)) {
sk->sk_cgrp = cg_proto;
}
rcu_read_unlock();
@@ -834,7 +835,7 @@ retry:
*/
__mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
- !css_tryget(&mz->memcg->css))
+ !css_tryget_online(&mz->memcg->css))
goto retry;
done:
return mz;
@@ -1076,7 +1077,7 @@ static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!memcg))
memcg = root_mem_cgroup;
- } while (!css_tryget(&memcg->css));
+ } while (!css_tryget_online(&memcg->css));
rcu_read_unlock();
return memcg;
}
@@ -1113,7 +1114,8 @@ skip_node:
*/
if (next_css) {
if ((next_css == &root->css) ||
- ((next_css->flags & CSS_ONLINE) && css_tryget(next_css)))
+ ((next_css->flags & CSS_ONLINE) &&
+ css_tryget_online(next_css)))
return mem_cgroup_from_css(next_css);
prev_css = next_css;
@@ -1159,7 +1161,7 @@ mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
* would be returned all the time.
*/
if (position && position != root &&
- !css_tryget(&position->css))
+ !css_tryget_online(&position->css))
position = NULL;
}
return position;
@@ -2785,9 +2787,9 @@ static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
/*
* A helper function to get mem_cgroup from ID. must be called under
- * rcu_read_lock(). The caller is responsible for calling css_tryget if
- * the mem_cgroup is used for charging. (dropping refcnt from swap can be
- * called against removed memcg.)
+ * rcu_read_lock(). The caller is responsible for calling
+ * css_tryget_online() if the mem_cgroup is used for charging. (dropping
+ * refcnt from swap can be called against removed memcg.)
*/
static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
{
@@ -2810,14 +2812,14 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
memcg = pc->mem_cgroup;
- if (memcg && !css_tryget(&memcg->css))
+ if (memcg && !css_tryget_online(&memcg->css))
memcg = NULL;
} else if (PageSwapCache(page)) {
ent.val = page_private(page);
id = lookup_swap_cgroup_id(ent);
rcu_read_lock();
memcg = mem_cgroup_lookup(id);
- if (memcg && !css_tryget(&memcg->css))
+ if (memcg && !css_tryget_online(&memcg->css))
memcg = NULL;
rcu_read_unlock();
}
@@ -3473,7 +3475,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
}
/* The corresponding put will be done in the workqueue. */
- if (!css_tryget(&memcg->css))
+ if (!css_tryget_online(&memcg->css))
goto out;
rcu_read_unlock();
@@ -4246,8 +4248,8 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent)
memcg = mem_cgroup_lookup(id);
if (memcg) {
/*
- * We uncharge this because swap is freed.
- * This memcg can be obsolete one. We avoid calling css_tryget
+ * We uncharge this because swap is freed. This memcg can
+ * be obsolete one. We avoid calling css_tryget_online().
*/
if (!mem_cgroup_is_root(memcg))
res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
@@ -5840,10 +5842,10 @@ static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
* which is then paired with css_put during uncharge resp. here.
*
* Although this might sound strange as this path is called from
- * css_offline() when the referencemight have dropped down to 0
- * and shouldn't be incremented anymore (css_tryget would fail)
- * we do not have other options because of the kmem allocations
- * lifetime.
+ * css_offline() when the referencemight have dropped down to 0 and
+ * shouldn't be incremented anymore (css_tryget_online() would
+ * fail) we do not have other options because of the kmem
+ * allocations lifetime.
*/
css_get(&memcg->css);
@@ -6051,8 +6053,8 @@ static int memcg_write_event_control(struct cgroup_subsys_state *css,
* automatically removed on cgroup destruction but the removal is
* asynchronous, so take an extra ref on @css.
*/
- cfile_css = css_tryget_from_dir(cfile.file->f_dentry->d_parent,
- &memory_cgrp_subsys);
+ cfile_css = css_tryget_online_from_dir(cfile.file->f_dentry->d_parent,
+ &memory_cgrp_subsys);
ret = -EINVAL;
if (IS_ERR(cfile_css))
goto out_put_cfile;
@@ -6496,7 +6498,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
/*
* XXX: css_offline() would be where we should reparent all
* memory to prepare the cgroup for destruction. However,
- * memcg does not do css_tryget() and res_counter charging
+ * memcg does not do css_tryget_online() and res_counter charging
* under the same RCU lock region, which means that charging
* could race with offlining. Offlining only happens to
* cgroups with no tasks in them but charges can show up
@@ -6510,9 +6512,9 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
* lookup_swap_cgroup_id()
* rcu_read_lock()
* mem_cgroup_lookup()
- * css_tryget()
+ * css_tryget_online()
* rcu_read_unlock()
- * disable css_tryget()
+ * disable css_tryget_online()
* call_rcu()
* offline_css()
* reparent_charges()