From 623f926b050e12b0f5e3a2f4d11c36e4ddd63541 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 13 Aug 2013 11:01:55 -0400 Subject: [PATCH] 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 Acked-by: Li Zefan --- kernel/cgroup.c | 50 +++++++++++++++++++++++-------------------------- 1 file changed, 23 insertions(+), 27 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c27101622567..a1ebc445f350 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -838,8 +838,7 @@ static struct backing_dev_info cgroup_backing_dev_info = { .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, }; -static int alloc_css_id(struct cgroup_subsys *ss, - struct cgroup *parent, struct cgroup *child); +static int alloc_css_id(struct cgroup_subsys_state *child_css); static struct inode *cgroup_new_inode(umode_t mode, struct super_block *sb) { @@ -4308,9 +4307,8 @@ static void css_release(struct percpu_ref *ref) schedule_work(&css->destroy_work); } -static void init_cgroup_css(struct cgroup_subsys_state *css, - struct cgroup_subsys *ss, - struct cgroup *cgrp) +static void init_css(struct cgroup_subsys_state *css, struct cgroup_subsys *ss, + struct cgroup *cgrp) { css->cgroup = cgrp; css->ss = ss; @@ -4327,9 +4325,9 @@ static void init_cgroup_css(struct cgroup_subsys_state *css, } /* invoke ->css_online() on a new CSS and mark it online if successful */ -static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) +static int online_css(struct cgroup_subsys_state *css) { - struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + struct cgroup_subsys *ss = css->ss; int ret = 0; lockdep_assert_held(&cgroup_mutex); @@ -4342,9 +4340,9 @@ static int online_css(struct cgroup_subsys *ss, struct cgroup *cgrp) } /* if the CSS is online, invoke ->css_offline() on it and mark it offline */ -static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp) +static void offline_css(struct cgroup_subsys_state *css) { - struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + struct cgroup_subsys *ss = css->ss; lockdep_assert_held(&cgroup_mutex); @@ -4442,10 +4440,10 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, goto err_free_all; } - init_cgroup_css(css, ss, cgrp); + init_css(css, ss, cgrp); if (ss->use_id) { - err = alloc_css_id(ss, parent, cgrp); + err = alloc_css_id(css); if (err) goto err_free_all; } @@ -4480,7 +4478,9 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, /* creation succeeded, notify subsystems */ for_each_root_subsys(root, ss) { - err = online_css(ss, cgrp); + struct cgroup_subsys_state *css = cgroup_css(cgrp, ss->subsys_id); + + err = online_css(css); if (err) goto err_destroy; @@ -4700,7 +4700,7 @@ static void cgroup_offline_fn(struct work_struct *work) * initate destruction. */ for_each_root_subsys(cgrp->root, ss) - offline_css(ss, cgrp); + offline_css(cgroup_css(cgrp, ss->subsys_id)); /* * Put the css refs from cgroup_destroy_locked(). Each css holds @@ -4778,7 +4778,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) css = ss->css_alloc(cgroup_css(cgroup_dummy_top, ss->subsys_id)); /* We don't handle early failures gracefully */ BUG_ON(IS_ERR(css)); - init_cgroup_css(css, ss, cgroup_dummy_top); + init_css(css, ss, cgroup_dummy_top); /* Update the init_css_set to contain a subsys * pointer to this state - since the subsystem is @@ -4793,7 +4793,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) * need to invoke fork callbacks here. */ BUG_ON(!list_empty(&init_task.tasks)); - BUG_ON(online_css(ss, cgroup_dummy_top)); + BUG_ON(online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id))); mutex_unlock(&cgroup_mutex); @@ -4866,8 +4866,8 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) ss->root = &cgroup_dummy_root; /* our new subsystem will be attached to the dummy hierarchy. */ - init_cgroup_css(css, ss, cgroup_dummy_top); - /* init_idr must be after init_cgroup_css because it sets css->id. */ + init_css(css, ss, cgroup_dummy_top); + /* init_idr must be after init_css() because it sets css->id. */ if (ss->use_id) { ret = cgroup_init_idr(ss, css); if (ret) @@ -4897,7 +4897,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss) } write_unlock(&css_set_lock); - ret = online_css(ss, cgroup_dummy_top); + ret = online_css(cgroup_css(cgroup_dummy_top, ss->subsys_id)); if (ret) goto err_unload; @@ -4936,7 +4936,7 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss) mutex_lock(&cgroup_mutex); - offline_css(ss, cgroup_dummy_top); + offline_css(cgroup_css(cgroup_dummy_top, ss->subsys_id)); if (ss->use_id) idr_destroy(&ss->idr); @@ -5588,20 +5588,16 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss, return 0; } -static int alloc_css_id(struct cgroup_subsys *ss, struct cgroup *parent, - struct cgroup *child) +static int alloc_css_id(struct cgroup_subsys_state *child_css) { - int subsys_id, i, depth = 0; - struct cgroup_subsys_state *parent_css, *child_css; + struct cgroup_subsys_state *parent_css = css_parent(child_css); struct css_id *child_id, *parent_id; + int i, depth; - subsys_id = ss->subsys_id; - parent_css = cgroup_css(parent, subsys_id); - child_css = cgroup_css(child, subsys_id); parent_id = rcu_dereference_protected(parent_css->id, true); depth = parent_id->depth + 1; - child_id = get_new_cssid(ss, depth); + child_id = get_new_cssid(child_css->ss, depth); if (IS_ERR(child_id)) return PTR_ERR(child_id); -- 2.20.1