Introduce thin wrappers which lock and unlock cgroup_mutex. While this doesn't introduce any functional differences now, they will later be used to perform some extra operations around locking.
Signed-off-by: Tejun Heo <[email protected]> --- kernel/cgroup.c | 100 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 59 insertions(+), 41 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index e22df5d8..2297bf6 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -237,6 +237,24 @@ static int cgroup_addrm_files(struct cgroup_subsys_state *css, bool is_add); /** + * cgroup_lock - lock cgroup_mutex and perform related operations + */ +static void cgroup_lock(void) + __acquires(&cgroup_mutex) +{ + mutex_lock(&cgroup_mutex); +} + +/** + * cgroup_unlock - unlock cgroup_mutex and perform related operations + */ +static void cgroup_unlock(void) + __releases(&cgroup_mutex) +{ + mutex_unlock(&cgroup_mutex); +} + +/** * cgroup_ssid_enabled - cgroup subsys enabled test by subsys ID * @ssid: subsys ID of interest * @@ -1194,7 +1212,7 @@ static void cgroup_destroy_root(struct cgroup_root *root) cgroup_exit_root_id(root); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); kernfs_destroy_root(root->kf_root); cgroup_free_root(root); @@ -1373,7 +1391,7 @@ static void cgroup_kn_unlock(struct kernfs_node *kn) else cgrp = kn->parent->priv; - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); kernfs_unbreak_active_protection(kn); cgroup_put(cgrp); @@ -1419,7 +1437,7 @@ static struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, if (drain_offline) cgroup_lock_and_drain_offline(cgrp); else - mutex_lock(&cgroup_mutex); + cgroup_lock(); if (!cgroup_is_dead(cgrp)) return cgrp; @@ -1804,7 +1822,7 @@ static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data) out_unlock: kfree(opts.release_agent); kfree(opts.name); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return ret; } @@ -2045,7 +2063,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, continue; if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) { - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); msleep(10); ret = restart_syscall(); goto out_free; @@ -2100,7 +2118,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, pinned_sb = kernfs_pin_sb(root->kf_root, NULL); if (IS_ERR(pinned_sb) || !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) { - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); if (!IS_ERR_OR_NULL(pinned_sb)) deactivate_super(pinned_sb); msleep(10); @@ -2135,7 +2153,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, cgroup_free_root(root); out_unlock: - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); out_free: kfree(opts.release_agent); kfree(opts.name); @@ -2214,7 +2232,7 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen) int hierarchy_id = 1; char *path = NULL; - mutex_lock(&cgroup_mutex); + cgroup_lock(); spin_lock_bh(&css_set_lock); root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id); @@ -2229,7 +2247,7 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen) } spin_unlock_bh(&css_set_lock); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return path; } EXPORT_SYMBOL_GPL(task_cgroup_path); @@ -2790,7 +2808,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) struct cgroup_root *root; int retval = 0; - mutex_lock(&cgroup_mutex); + cgroup_lock(); for_each_root(root) { struct cgroup *from_cgrp; @@ -2805,7 +2823,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) if (retval) break; } - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return retval; } @@ -2968,7 +2986,7 @@ static void cgroup_lock_and_drain_offline(struct cgroup *cgrp) int ssid; restart: - mutex_lock(&cgroup_mutex); + cgroup_lock(); cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) { for_each_subsys(ss, ssid) { @@ -2982,7 +3000,7 @@ static void cgroup_lock_and_drain_offline(struct cgroup *cgrp) prepare_to_wait(&dsct->offline_waitq, &wait, TASK_UNINTERRUPTIBLE); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); schedule(); finish_wait(&dsct->offline_waitq, &wait); @@ -3426,11 +3444,11 @@ static int cgroup_rename(struct kernfs_node *kn, struct kernfs_node *new_parent, kernfs_break_active_protection(new_parent); kernfs_break_active_protection(kn); - mutex_lock(&cgroup_mutex); + cgroup_lock(); ret = kernfs_rename(kn, new_parent, new_name_str); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); kernfs_unbreak_active_protection(kn); kernfs_unbreak_active_protection(new_parent); @@ -3637,9 +3655,9 @@ int cgroup_rm_cftypes(struct cftype *cfts) { int ret; - mutex_lock(&cgroup_mutex); + cgroup_lock(); ret = cgroup_rm_cftypes_locked(cfts); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return ret; } @@ -3671,14 +3689,14 @@ static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts) if (ret) return ret; - mutex_lock(&cgroup_mutex); + cgroup_lock(); list_add_tail(&cfts->node, &ss->cfts); ret = cgroup_apply_cftypes(cfts, true); if (ret) cgroup_rm_cftypes_locked(cfts); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return ret; } @@ -4170,7 +4188,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) if (!cgroup_may_migrate_to(to)) return -EBUSY; - mutex_lock(&cgroup_mutex); + cgroup_lock(); /* all tasks in @from are being moved, all csets are source */ spin_lock_bh(&css_set_lock); @@ -4200,7 +4218,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) } while (task && !ret); out_err: cgroup_migrate_finish(&preloaded_csets); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return ret; } @@ -4507,7 +4525,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) kernfs_type(kn) != KERNFS_DIR) return -EINVAL; - mutex_lock(&cgroup_mutex); + cgroup_lock(); /* * We aren't being called from kernfs and there's no guarantee on @@ -4518,7 +4536,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) cgrp = rcu_dereference(kn->priv); if (!cgrp || cgroup_is_dead(cgrp)) { rcu_read_unlock(); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return -ENOENT; } rcu_read_unlock(); @@ -4546,7 +4564,7 @@ int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) } css_task_iter_end(&it); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return 0; } @@ -4847,7 +4865,7 @@ static void css_release_work_fn(struct work_struct *work) struct cgroup_subsys *ss = css->ss; struct cgroup *cgrp = css->cgroup; - mutex_lock(&cgroup_mutex); + cgroup_lock(); css->flags |= CSS_RELEASED; list_del_rcu(&css->sibling); @@ -4874,7 +4892,7 @@ static void css_release_work_fn(struct work_struct *work) NULL); } - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); call_rcu(&css->rcu_head, css_free_rcu_fn); } @@ -5168,7 +5186,7 @@ static void css_killed_work_fn(struct work_struct *work) struct cgroup_subsys_state *css = container_of(work, struct cgroup_subsys_state, destroy_work); - mutex_lock(&cgroup_mutex); + cgroup_lock(); do { offline_css(css); @@ -5177,7 +5195,7 @@ static void css_killed_work_fn(struct work_struct *work) css = css->parent; } while (css && atomic_dec_and_test(&css->online_cnt)); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); } /* css kill confirmation processing requires process context, bounce */ @@ -5330,7 +5348,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early) pr_debug("Initializing cgroup subsys %s\n", ss->name); - mutex_lock(&cgroup_mutex); + cgroup_lock(); idr_init(&ss->css_idr); INIT_LIST_HEAD(&ss->cfts); @@ -5374,7 +5392,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early) BUG_ON(online_css(css)); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); } /** @@ -5431,7 +5449,7 @@ int __init cgroup_init(void) BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files)); BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files)); - mutex_lock(&cgroup_mutex); + cgroup_lock(); /* * Add init_css_set to the hash table so that dfl_root can link to @@ -5442,7 +5460,7 @@ int __init cgroup_init(void) BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0)); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); for_each_subsys(ss, ssid) { if (ss->early_init) { @@ -5548,7 +5566,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, if (!buf) goto out; - mutex_lock(&cgroup_mutex); + cgroup_lock(); spin_lock_bh(&css_set_lock); for_each_root(root) { @@ -5602,7 +5620,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, retval = 0; out_unlock: spin_unlock_bh(&css_set_lock); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); kfree(buf); out: return retval; @@ -5620,7 +5638,7 @@ static int proc_cgroupstats_show(struct seq_file *m, void *v) * cgroup_mutex is also necessary to guarantee an atomic snapshot of * subsys/hierarchy state. */ - mutex_lock(&cgroup_mutex); + cgroup_lock(); for_each_subsys(ss, i) seq_printf(m, "%s\t%d\t%d\t%d\n", @@ -5628,7 +5646,7 @@ static int proc_cgroupstats_show(struct seq_file *m, void *v) atomic_read(&ss->root->nr_cgrps), cgroup_ssid_enabled(i)); - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return 0; } @@ -5860,7 +5878,7 @@ static void cgroup_release_agent(struct work_struct *work) char *pathbuf = NULL, *agentbuf = NULL, *path; char *argv[3], *envp[3]; - mutex_lock(&cgroup_mutex); + cgroup_lock(); pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL); @@ -5880,11 +5898,11 @@ static void cgroup_release_agent(struct work_struct *work) envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; envp[2] = NULL; - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); goto out_free; out: - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); out_free: kfree(agentbuf); kfree(pathbuf); @@ -6006,7 +6024,7 @@ struct cgroup *cgroup_get_from_path(const char *path) struct kernfs_node *kn; struct cgroup *cgrp; - mutex_lock(&cgroup_mutex); + cgroup_lock(); kn = kernfs_walk_and_get(cgrp_dfl_root.cgrp.kn, path); if (kn) { @@ -6021,7 +6039,7 @@ struct cgroup *cgroup_get_from_path(const char *path) cgrp = ERR_PTR(-ENOENT); } - mutex_unlock(&cgroup_mutex); + cgroup_unlock(); return cgrp; } EXPORT_SYMBOL_GPL(cgroup_get_from_path); -- 2.5.0
