diff options
Diffstat (limited to 'include/linux/blk-cgroup.h')
| -rw-r--r-- | include/linux/blk-cgroup.h | 41 |
1 files changed, 0 insertions, 41 deletions
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index f11c37f8ce09..284819a4d122 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -247,47 +247,6 @@ static inline struct cgroup_subsys_state *blkcg_css(void) return task_css(current, io_cgrp_id); } -/** - * blkcg_get_css - find and get a reference to the css - * - * Find the css associated with either the kthread or the current task. - * This takes a reference on the blkcg which will need to be managed by the - * caller. - */ -static inline struct cgroup_subsys_state *blkcg_get_css(void) -{ - struct cgroup_subsys_state *css; - - rcu_read_lock(); - - css = kthread_blkcg(); - if (css) { - css_get(css); - } else { - /* - * This is a bit complicated. It is possible task_css() is - * seeing an old css pointer here. This is caused by the - * current thread migrating away from this cgroup and this - * cgroup dying. css_tryget() will fail when trying to take a - * ref on a cgroup that's ref count has hit 0. - * - * Therefore, if it does fail, this means current must have - * been swapped away already and this is waiting for it to - * propagate on the polling cpu. Hence the use of cpu_relax(). - */ - while (true) { - css = task_css(current, io_cgrp_id); - if (likely(css_tryget(css))) - break; - cpu_relax(); - } - } - - rcu_read_unlock(); - - return css; -} - static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) { return css ? container_of(css, struct blkcg, css) : NULL; |