diff options
author | Tejun Heo <tj@kernel.org> | 2013-12-06 15:11:56 -0500 |
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committer | Tejun Heo <tj@kernel.org> | 2013-12-06 15:11:56 -0500 |
commit | c81c925ad9b0460a14ec35b52c61158da0733d51 (patch) | |
tree | 4dfa8b6cb6b16cc900cfc218e5a46989fe11a758 /kernel/cgroup.c | |
parent | 9d403e99238ed6d7151a2c07db6cf8f6932ef3d5 (diff) | |
download | linux-c81c925ad9b0460a14ec35b52c61158da0733d51.tar.bz2 |
cgroup: factor out cgroup_subsys_state creation into create_css()
Now that all opertations to create a css (cgroup_subsys_state) are
collected into a single loop in cgroup_create(), it's easy to factor
it out into its own function. Factor out css creation into
create_css(). This makes the code easier to follow and will enable
decoupling css creation from cgroup creation which is necessary for
the planned unified hierarchy.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r-- | kernel/cgroup.c | 95 |
1 files changed, 57 insertions, 38 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 39e2295466ec..d12c29f42feb 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4073,6 +4073,62 @@ static void offline_css(struct cgroup_subsys_state *css) RCU_INIT_POINTER(css->cgroup->subsys[ss->subsys_id], css); } +/** + * create_css - create a cgroup_subsys_state + * @cgrp: the cgroup new css will be associated with + * @ss: the subsys of new css + * + * Create a new css associated with @cgrp - @ss pair. On success, the new + * css is online and installed in @cgrp with all interface files created. + * Returns 0 on success, -errno on failure. + */ +static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss) +{ + struct cgroup *parent = cgrp->parent; + struct cgroup_subsys_state *css; + int err; + + lockdep_assert_held(&cgrp->dentry->d_inode->i_mutex); + lockdep_assert_held(&cgroup_mutex); + + css = ss->css_alloc(cgroup_css(parent, ss)); + if (IS_ERR(css)) + return PTR_ERR(css); + + err = percpu_ref_init(&css->refcnt, css_release); + if (err) + goto err_free; + + init_css(css, ss, cgrp); + + err = cgroup_populate_dir(cgrp, 1 << ss->subsys_id); + if (err) + goto err_free; + + err = online_css(css); + if (err) + goto err_free; + + dget(cgrp->dentry); + css_get(css->parent); + + if (ss->broken_hierarchy && !ss->warned_broken_hierarchy && + parent->parent) { + pr_warning("cgroup: %s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n", + current->comm, current->pid, ss->name); + if (!strcmp(ss->name, "memory")) + pr_warning("cgroup: \"memory\" requires setting use_hierarchy to 1 on the root.\n"); + ss->warned_broken_hierarchy = true; + } + + return 0; + +err_free: + percpu_ref_cancel_init(&css->refcnt); + ss->css_free(css); + return err; +} + /* * cgroup_create - create a cgroup * @parent: cgroup that will be parent of the new cgroup @@ -4084,7 +4140,6 @@ static void offline_css(struct cgroup_subsys_state *css) static long cgroup_create(struct cgroup *parent, struct dentry *dentry, umode_t mode) { - struct cgroup_subsys_state *css = NULL; struct cgroup *cgrp; struct cgroup_name *name; struct cgroupfs_root *root = parent->root; @@ -4175,41 +4230,9 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, /* let's create and online css's */ for_each_root_subsys(root, ss) { - css = ss->css_alloc(cgroup_css(parent, ss)); - if (IS_ERR(css)) { - err = PTR_ERR(css); - css = NULL; - goto err_destroy; - } - - err = percpu_ref_init(&css->refcnt, css_release); + err = create_css(cgrp, ss); if (err) goto err_destroy; - - init_css(css, ss, cgrp); - - err = cgroup_populate_dir(cgrp, 1 << ss->subsys_id); - if (err) - goto err_destroy; - - err = online_css(css); - if (err) - goto err_destroy; - - dget(dentry); - css_get(css->parent); - - /* mark it consumed for error path */ - css = NULL; - - if (ss->broken_hierarchy && !ss->warned_broken_hierarchy && - parent->parent) { - pr_warning("cgroup: %s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n", - current->comm, current->pid, ss->name); - if (!strcmp(ss->name, "memory")) - pr_warning("cgroup: \"memory\" requires setting use_hierarchy to 1 on the root.\n"); - ss->warned_broken_hierarchy = true; - } } mutex_unlock(&cgroup_mutex); @@ -4230,10 +4253,6 @@ err_free_cgrp: return err; err_destroy: - if (css) { - percpu_ref_cancel_init(&css->refcnt); - css->ss->css_free(css); - } cgroup_destroy_locked(cgrp); mutex_unlock(&cgroup_mutex); mutex_unlock(&dentry->d_inode->i_mutex); |