[PATCH v11 01/13] cgroup: Added cgroup_get_from_id
From: Muneendra Kumar <hidden>
Date: 2021-06-08 11:36:31
Also in:
linux-block, linux-scsi
Subsystem:
control group (cgroup), the rest · Maintainers:
Tejun Heo, Johannes Weiner, Michal Koutný, Linus Torvalds
From: Muneendra <redacted> Added a new function cgroup_get_from_id to retrieve the cgroup associated with cgroup id. Exported the same as this can be used by blk-cgorup.c Added function declaration of cgroup_get_from_id in cgorup.h This patch also exported the function cgroup_get_e_css as this is getting used in blk-cgroup.h Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Himanshu Madhani <redacted> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Muneendra <redacted> --- v11: No change v10: No change v9: Addressed the issues reported by kernel test robot v8: No change v7: No change v6: No change v5: renamed the function cgroup_get_from_kernfs_id to cgroup_get_from_id v4: No change v3: Exported the cgroup_get_e_css v2: New patch --- include/linux/cgroup.h | 6 ++++++ kernel/cgroup/cgroup.c | 26 ++++++++++++++++++++++++++ 2 files changed, 32 insertions(+)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 4f2f79de083e..d2eace88d9d1 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h@@ -696,6 +696,7 @@ static inline void cgroup_kthread_ready(void) } void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen); +struct cgroup *cgroup_get_from_id(u64 id); #else /* !CONFIG_CGROUPS */ struct cgroup_subsys_state;
@@ -743,6 +744,11 @@ static inline bool task_under_cgroup_hierarchy(struct task_struct *task, static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) {} + +static inline struct cgroup *cgroup_get_from_id(u64 id) +{ + return NULL; +} #endif /* !CONFIG_CGROUPS */ #ifdef CONFIG_CGROUPS
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index e049edd66776..bd3251d4fcc7 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c@@ -577,6 +577,7 @@ struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgrp, rcu_read_unlock(); return css; } +EXPORT_SYMBOL_GPL(cgroup_get_e_css); static void cgroup_get_live(struct cgroup *cgrp) {
@@ -5776,6 +5777,31 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) kernfs_put(kn); } +/* + * cgroup_get_from_id : get the cgroup associated with cgroup id + * @id: cgroup id + * On success it returns the cgrp on failure it returns NULL + */ +struct cgroup *cgroup_get_from_id(u64 id) +{ + struct kernfs_node *kn; + struct cgroup *cgrp = NULL; + + mutex_lock(&cgroup_mutex); + kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id); + if (!kn) + goto out_unlock; + + cgrp = kn->priv; + if (cgroup_is_dead(cgrp) || !cgroup_tryget(cgrp)) + cgrp = NULL; + kernfs_put(kn); +out_unlock: + mutex_unlock(&cgroup_mutex); + return cgrp; +} +EXPORT_SYMBOL_GPL(cgroup_get_from_id); + /* * proc_cgroup_show() * - Print task's cgroup paths into seq_file, one line for each hierarchy
--
2.26.2
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