cgroup: make cgroup_write_event_control() use css_from_dir() instead of __d_cgrp()

cgroup_event will be moved to its only user - memcg.  Replace
__d_cgrp() usage with css_from_dir(), which is already exported.  This
also simplifies the code a bit.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
This commit is contained in:
Tejun Heo 2013-08-26 18:40:56 -04:00
parent 7941cb027d
commit 7c918cbbd8
1 changed files with 5 additions and 13 deletions

View File

@ -4041,7 +4041,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
{ {
struct cgroup *cgrp = dummy_css->cgroup; struct cgroup *cgrp = dummy_css->cgroup;
struct cgroup_event *event; struct cgroup_event *event;
struct cgroup *cgrp_cfile; struct cgroup_subsys_state *cfile_css;
unsigned int efd, cfd; unsigned int efd, cfd;
struct file *efile; struct file *efile;
struct file *cfile; struct file *cfile;
@ -4103,7 +4103,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
} }
/* /*
* Determine the css of @cfile and associate @event with it. * Determine the css of @cfile, verify it belongs to the same
* cgroup as cgroup.event_control, and associate @event with it.
* Remaining events are automatically removed on cgroup destruction * Remaining events are automatically removed on cgroup destruction
* but the removal is asynchronous, so take an extra ref. * but the removal is asynchronous, so take an extra ref.
*/ */
@ -4111,23 +4112,14 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css,
ret = -EINVAL; ret = -EINVAL;
event->css = cgroup_css(cgrp, event->cft->ss); event->css = cgroup_css(cgrp, event->cft->ss);
if (event->css && css_tryget(event->css)) cfile_css = css_from_dir(cfile->f_dentry->d_parent, event->cft->ss);
if (event->css && event->css == cfile_css && css_tryget(event->css))
ret = 0; ret = 0;
rcu_read_unlock(); rcu_read_unlock();
if (ret) if (ret)
goto out_put_cfile; goto out_put_cfile;
/*
* The file to be monitored must be in the same cgroup as
* cgroup.event_control is.
*/
cgrp_cfile = __d_cgrp(cfile->f_dentry->d_parent);
if (cgrp_cfile != cgrp) {
ret = -EINVAL;
goto out_put_css;
}
if (!event->cft->register_event || !event->cft->unregister_event) { if (!event->cft->register_event || !event->cft->unregister_event) {
ret = -EINVAL; ret = -EINVAL;
goto out_put_css; goto out_put_css;