diff options
author | Tejun Heo <tj@kernel.org> | 2013-08-08 20:11:23 -0400 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2013-08-08 20:11:23 -0400 |
commit | 6387698699afd72d6304566fb6ccf84bffe07c56 (patch) | |
tree | 9440e96fa8e5adce62409a5b0e40984dfedaada3 /security/device_cgroup.c | |
parent | a7c6d554aa01236ac2a9f851ab0f75704f76dfa2 (diff) | |
download | op-kernel-dev-6387698699afd72d6304566fb6ccf84bffe07c56.zip op-kernel-dev-6387698699afd72d6304566fb6ccf84bffe07c56.tar.gz |
cgroup: add css_parent()
Currently, controllers have to explicitly follow the cgroup hierarchy
to find the parent of a given css. cgroup is moving towards using
cgroup_subsys_state as the main controller interface construct, so
let's provide a way to climb the hierarchy using just csses.
This patch implements css_parent() which, given a css, returns its
parent. The function is guarnateed to valid non-NULL parent css as
long as the target css is not at the top of the hierarchy.
freezer, cpuset, cpu, cpuacct, hugetlb, memory, net_cls and devices
are converted to use css_parent() instead of accessing cgroup->parent
directly.
* __parent_ca() is dropped from cpuacct and its usage is replaced with
parent_ca(). The only difference between the two was NULL test on
cgroup->parent which is now embedded in css_parent() making the
distinction moot. Note that eventually a css->parent field will be
added to css and the NULL check in css_parent() will go away.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'security/device_cgroup.c')
-rw-r--r-- | security/device_cgroup.c | 18 |
1 files changed, 5 insertions, 13 deletions
diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 9095364..635a49d 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -198,13 +198,11 @@ static inline bool is_devcg_online(const struct dev_cgroup *devcg) */ static int devcgroup_online(struct cgroup *cgroup) { - struct dev_cgroup *dev_cgroup, *parent_dev_cgroup = NULL; + struct dev_cgroup *dev_cgroup = cgroup_to_devcgroup(cgroup); + struct dev_cgroup *parent_dev_cgroup = css_to_devcgroup(css_parent(&dev_cgroup->css)); int ret = 0; mutex_lock(&devcgroup_mutex); - dev_cgroup = cgroup_to_devcgroup(cgroup); - if (cgroup->parent) - parent_dev_cgroup = cgroup_to_devcgroup(cgroup->parent); if (parent_dev_cgroup == NULL) dev_cgroup->behavior = DEVCG_DEFAULT_ALLOW; @@ -394,12 +392,10 @@ static bool may_access(struct dev_cgroup *dev_cgroup, static int parent_has_perm(struct dev_cgroup *childcg, struct dev_exception_item *ex) { - struct cgroup *pcg = childcg->css.cgroup->parent; - struct dev_cgroup *parent; + struct dev_cgroup *parent = css_to_devcgroup(css_parent(&childcg->css)); - if (!pcg) + if (!parent) return 1; - parent = cgroup_to_devcgroup(pcg); return may_access(parent, ex, childcg->behavior); } @@ -524,15 +520,11 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, char temp[12]; /* 11 + 1 characters needed for a u32 */ int count, rc = 0; struct dev_exception_item ex; - struct cgroup *p = devcgroup->css.cgroup; - struct dev_cgroup *parent = NULL; + struct dev_cgroup *parent = css_to_devcgroup(css_parent(&devcgroup->css)); if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (p->parent) - parent = cgroup_to_devcgroup(p->parent); - memset(&ex, 0, sizeof(ex)); b = buffer; |