diff options
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index a41dc87..12237a2 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3969,7 +3969,6 @@ static void cgroup_event_remove(struct work_struct *work) struct cgroup_event *event = container_of(work, struct cgroup_event, remove); struct cgroup_subsys_state *css = event->css; - struct cgroup *cgrp = css->cgroup; remove_wait_queue(event->wqh, &event->wait); @@ -3980,7 +3979,7 @@ static void cgroup_event_remove(struct work_struct *work) eventfd_ctx_put(event->eventfd); kfree(event); - cgroup_dput(cgrp); + css_put(css); } /* @@ -4103,12 +4102,16 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css, goto out_put_cfile; } - /* determine the css of @cfile and associate @event with it */ + /* + * Determine the css of @cfile and associate @event with it. + * Remaining events are automatically removed on cgroup destruction + * but the removal is asynchronous, so take an extra ref. + */ rcu_read_lock(); ret = -EINVAL; event->css = cgroup_css(cgrp, event->cft->ss); - if (event->css) + if (event->css && css_tryget(event->css)) ret = 0; rcu_read_unlock(); @@ -4122,28 +4125,21 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css, cgrp_cfile = __d_cgrp(cfile->f_dentry->d_parent); if (cgrp_cfile != cgrp) { ret = -EINVAL; - goto out_put_cfile; + goto out_put_css; } if (!event->cft->register_event || !event->cft->unregister_event) { ret = -EINVAL; - goto out_put_cfile; + goto out_put_css; } ret = event->cft->register_event(event->css, event->cft, event->eventfd, buffer); if (ret) - goto out_put_cfile; + goto out_put_css; efile->f_op->poll(efile, &event->pt); - /* - * Events should be removed after rmdir of cgroup directory, but before - * destroying subsystem state objects. Let's take reference to cgroup - * directory dentry to do that. - */ - dget(cgrp->dentry); - spin_lock(&cgrp->event_list_lock); list_add(&event->list, &cgrp->event_list); spin_unlock(&cgrp->event_list_lock); @@ -4153,6 +4149,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *dummy_css, return 0; +out_put_css: + css_put(event->css); out_put_cfile: fput(cfile); out_put_eventfd: |