cgroup: reorganize css init / exit paths
css (cgroup_subsys_state) lifetime management is about to be restructured. In prepartion, make the following mostly trivial changes. * init_cgroup_css() is renamed to init_css() so that it's consistent with other css handling functions. * alloc_css_id(), online_css() and offline_css() updated to take @css instead of cgroups and subsys IDs. This patch doesn't make any functional changes. v2: v1 merged two for_each_root_subsys() loops in cgroup_create() but Li Zefan pointed out that it breaks error path. Dropped. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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73e80ed800
Коммит
623f926b05
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@ -838,8 +838,7 @@ static struct backing_dev_info cgroup_backing_dev_info = {
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.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
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};
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static int alloc_css_id(struct cgroup_subsys *ss,
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struct cgroup *parent, struct cgroup *child);
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static int alloc_css_id(struct cgroup_subsys_state *child_css);
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static struct inode *cgroup_new_inode(umode_t mode, struct super_block *sb)
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{
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@ -4308,9 +4307,8 @@ static void css_release(struct percpu_ref *ref)
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schedule_work(&css->destroy_work);
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}
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static void init_cgroup_css(struct cgroup_subsys_state *css,
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struct cgroup_subsys *ss,
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struct cgroup *cgrp)
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static void init_css(struct cgroup_subsys_state *css, struct cgroup_subsys *ss,
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struct cgroup *cgrp)
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{
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css->cgroup = cgrp;
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css->ss = ss;
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@ -4327,9 +4325,9 @@ static void init_cgroup_css(struct cgroup_subsys_state *css,
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}
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/* invoke ->css_online() on a new CSS and mark it online if successful */
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static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp)
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static int online_css(struct cgroup_subsys_state *css)
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{
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struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id);
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struct cgroup_subsys *ss = css->ss;
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int ret = 0;
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lockdep_assert_held(&cgroup_mutex);
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@ -4342,9 +4340,9 @@ static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp)
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}
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/* if the CSS is online, invoke ->css_offline() on it and mark it offline */
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static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp)
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static void offline_css(struct cgroup_subsys_state *css)
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{
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struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id);
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struct cgroup_subsys *ss = css->ss;
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lockdep_assert_held(&cgroup_mutex);
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@ -4442,10 +4440,10 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
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goto err_free_all;
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}
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init_cgroup_css(css, ss, cgrp);
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init_css(css, ss, cgrp);
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if (ss->use_id) {
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err = alloc_css_id(ss, parent, cgrp);
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err = alloc_css_id(css);
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if (err)
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goto err_free_all;
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}
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@ -4480,7 +4478,9 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
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/* creation succeeded, notify subsystems */
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for_each_root_subsys(root, ss) {
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err = online_css(ss, cgrp);
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struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id);
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err = online_css(css);
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if (err)
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goto err_destroy;
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@ -4700,7 +4700,7 @@ static void cgroup_offline_fn(struct work_struct *work)
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* initate destruction.
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*/
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for_each_root_subsys(cgrp->root, ss)
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offline_css(ss, cgrp);
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offline_css(cgroup_css(cgrp, ss->subsys_id));
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/*
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* Put the css refs from cgroup_destroy_locked(). Each css holds
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@ -4778,7 +4778,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
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css = ss->css_alloc(cgroup_css(cgroup_dummy_top, ss->subsys_id));
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/* We don't handle early failures gracefully */
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BUG_ON(IS_ERR(css));
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init_cgroup_css(css, ss, cgroup_dummy_top);
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init_css(css, ss, cgroup_dummy_top);
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/* Update the init_css_set to contain a subsys
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* pointer to this state - since the subsystem is
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@ -4793,7 +4793,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
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* need to invoke fork callbacks here. */
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BUG_ON(!list_empty(&init_task.tasks));
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BUG_ON(online_css(ss, cgroup_dummy_top));
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BUG_ON(online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id)));
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mutex_unlock(&cgroup_mutex);
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@ -4866,8 +4866,8 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
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ss->root = &cgroup_dummy_root;
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/* our new subsystem will be attached to the dummy hierarchy. */
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init_cgroup_css(css, ss, cgroup_dummy_top);
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/* init_idr must be after init_cgroup_css because it sets css->id. */
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init_css(css, ss, cgroup_dummy_top);
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/* init_idr must be after init_css() because it sets css->id. */
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if (ss->use_id) {
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ret = cgroup_init_idr(ss, css);
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if (ret)
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@ -4897,7 +4897,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
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}
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write_unlock(&css_set_lock);
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ret = online_css(ss, cgroup_dummy_top);
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ret = online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id));
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if (ret)
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goto err_unload;
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@ -4936,7 +4936,7 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss)
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mutex_lock(&cgroup_mutex);
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offline_css(ss, cgroup_dummy_top);
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offline_css(cgroup_css(cgroup_dummy_top, ss->subsys_id));
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if (ss->use_id)
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idr_destroy(&ss->idr);
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@ -5588,20 +5588,16 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss,
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return 0;
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}
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static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent,
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struct cgroup *child)
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static int alloc_css_id(struct cgroup_subsys_state *child_css)
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{
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int subsys_id, i, depth = 0;
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struct cgroup_subsys_state *parent_css, *child_css;
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struct cgroup_subsys_state *parent_css = css_parent(child_css);
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struct css_id *child_id, *parent_id;
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int i, depth;
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subsys_id = ss->subsys_id;
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parent_css = cgroup_css(parent, subsys_id);
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child_css = cgroup_css(child, subsys_id);
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parent_id = rcu_dereference_protected(parent_css->id, true);
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depth = parent_id->depth + 1;
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child_id = get_new_cssid(ss, depth);
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child_id = get_new_cssid(child_css->ss, depth);
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if (IS_ERR(child_id))
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return PTR_ERR(child_id);
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