From 03970d3c11faf870dc5126bb2e84fd1d692af1b7 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 3 Mar 2016 09:58:00 -0500 Subject: [PATCH] cgroup: use cgroup_apply_enable_control() in cgroup creation path cgroup_create() manually updates control masks and creates child csses which cgroup_mkdir() then manually populates. Both can be simplified by using cgroup_apply_enable_control() and friends. The only catch is that it calls css_populate_dir() with NULL cgroup->kn during cgroup_create(). This is worked around by making the function noop on NULL kn. Signed-off-by: Tejun Heo Acked-by: Zefan Li --- kernel/cgroup.c | 38 ++++++++++++++------------------------ 1 file changed, 14 insertions(+), 24 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index bbeb35f14eda..ee6951b1e35d 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1490,7 +1490,7 @@ static int css_populate_dir(struct cgroup_subsys_state *css, struct cftype *cfts, *failed_cfts; int ret; - if (css->flags & CSS_VISIBLE) + if ((css->flags & CSS_VISIBLE) || !cgrp->kn) return 0; if (!css->ss) { @@ -5042,10 +5042,9 @@ err_free_css: static struct cgroup *cgroup_create(struct cgroup *parent) { struct cgroup_root *root = parent->root; - struct cgroup_subsys *ss; struct cgroup *cgrp, *tcgrp; int level = parent->level + 1; - int ssid, ret; + int ret; /* allocate the cgroup and its ID, 0 is reserved for the root */ cgrp = kzalloc(sizeof(*cgrp) + @@ -5095,25 +5094,19 @@ static struct cgroup *cgroup_create(struct cgroup *parent) */ cgroup_idr_replace(&root->cgroup_idr, cgrp, cgrp->id); - /* create the csses */ - do_each_subsys_mask(ss, ssid, cgroup_ss_mask(cgrp)) { - struct cgroup_subsys_state *css; - - css = css_create(cgrp, ss); - if (IS_ERR(css)) { - ret = PTR_ERR(css); - goto out_destroy; - } - } while_each_subsys_mask(); - /* * On the default hierarchy, a child doesn't automatically inherit * subtree_control from the parent. Each is configured manually. */ - if (!cgroup_on_dfl(cgrp)) { + if (!cgroup_on_dfl(cgrp)) cgrp->subtree_control = cgroup_control(cgrp); - cgroup_refresh_subtree_ss_mask(cgrp); - } + + cgroup_propagate_control(cgrp); + + /* @cgrp doesn't have dir yet so the following will only create csses */ + ret = cgroup_apply_control_enable(cgrp); + if (ret) + goto out_destroy; return cgrp; @@ -5131,9 +5124,8 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode) { struct cgroup *parent, *cgrp; - struct cgroup_subsys *ss; struct kernfs_node *kn; - int ssid, ret; + int ret; /* do not accept '\n' to prevent making /proc//cgroup unparsable */ if (strchr(name, '\n')) @@ -5171,11 +5163,9 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, if (ret) goto out_destroy; - do_each_subsys_mask(ss, ssid, cgroup_control(cgrp)) { - ret = css_populate_dir(cgroup_css(cgrp, ss), NULL); - if (ret) - goto out_destroy; - } while_each_subsys_mask(); + ret = cgroup_apply_control_enable(cgrp); + if (ret) + goto out_destroy; /* let's create and online css's */ kernfs_activate(kn);