diff options
| -rw-r--r-- | kernel/cgroup.c | 107 |
1 files changed, 28 insertions, 79 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index ee6951b1e35d..98e644b0a532 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -221,6 +221,8 @@ static struct cftype cgroup_legacy_base_files[]; static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask); static void cgroup_lock_and_drain_offline(struct cgroup *cgrp); +static int cgroup_apply_control(struct cgroup *cgrp); +static void cgroup_finalize_control(struct cgroup *cgrp, int ret); static void css_task_iter_advance(struct css_task_iter *it); static int cgroup_destroy_locked(struct cgroup *cgrp); static struct cgroup_subsys_state *css_create(struct cgroup *cgrp, @@ -1160,13 +1162,13 @@ static void cgroup_destroy_root(struct cgroup_root *root) struct cgroup *cgrp = &root->cgrp; struct cgrp_cset_link *link, *tmp_link; - mutex_lock(&cgroup_mutex); + cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); BUG_ON(atomic_read(&root->nr_cgrps)); BUG_ON(!list_empty(&cgrp->self.children)); /* Rebind all subsystems back to the default hierarchy */ - rebind_subsystems(&cgrp_dfl_root, root->subsys_mask); + WARN_ON(rebind_subsystems(&cgrp_dfl_root, root->subsys_mask)); /* * Release all the links from cset_links to this hierarchy's @@ -1352,19 +1354,6 @@ static u16 cgroup_calc_subtree_ss_mask(struct cgroup *cgrp, u16 subtree_control) } /** - * cgroup_refresh_subtree_ss_mask - update subtree_ss_mask - * @cgrp: the target cgroup - * - * Update @cgrp->subtree_ss_mask according to the current - * @cgrp->subtree_control using cgroup_calc_subtree_ss_mask(). - */ -static void cgroup_refresh_subtree_ss_mask(struct cgroup *cgrp) -{ - cgrp->subtree_ss_mask = - cgroup_calc_subtree_ss_mask(cgrp, cgrp->subtree_control); -} - -/** * cgroup_kn_unlock - unlocking helper for cgroup kernfs methods * @kn: the kernfs_node being serviced * @@ -1459,12 +1448,10 @@ static void cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft) /** * css_clear_dir - remove subsys files in a cgroup directory * @css: taget css - * @cgrp_override: specify if target cgroup is different from css->cgroup */ -static void css_clear_dir(struct cgroup_subsys_state *css, - struct cgroup *cgrp_override) +static void css_clear_dir(struct cgroup_subsys_state *css) { - struct cgroup *cgrp = cgrp_override ?: css->cgroup; + struct cgroup *cgrp = css->cgroup; struct cftype *cfts; if (!(css->flags & CSS_VISIBLE)) @@ -1479,14 +1466,12 @@ static void css_clear_dir(struct cgroup_subsys_state *css, /** * css_populate_dir - create subsys files in a cgroup directory * @css: target css - * @cgrp_overried: specify if target cgroup is different from css->cgroup * * On failure, no file is added. */ -static int css_populate_dir(struct cgroup_subsys_state *css, - struct cgroup *cgrp_override) +static int css_populate_dir(struct cgroup_subsys_state *css) { - struct cgroup *cgrp = cgrp_override ?: css->cgroup; + struct cgroup *cgrp = css->cgroup; struct cftype *cfts, *failed_cfts; int ret; @@ -1526,7 +1511,6 @@ static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask) { struct cgroup *dcgrp = &dst_root->cgrp; struct cgroup_subsys *ss; - u16 tmp_ss_mask; int ssid, i, ret; lockdep_assert_held(&cgroup_mutex); @@ -1541,46 +1525,6 @@ static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask) return -EBUSY; } while_each_subsys_mask(); - /* skip creating root files on dfl_root for inhibited subsystems */ - tmp_ss_mask = ss_mask; - if (dst_root == &cgrp_dfl_root) - tmp_ss_mask &= ~cgrp_dfl_inhibit_ss_mask; - - do_each_subsys_mask(ss, ssid, tmp_ss_mask) { - struct cgroup *scgrp = &ss->root->cgrp; - int tssid; - - ret = css_populate_dir(cgroup_css(scgrp, ss), dcgrp); - if (!ret) - continue; - - /* - * Rebinding back to the default root is not allowed to - * fail. Using both default and non-default roots should - * be rare. Moving subsystems back and forth even more so. - * Just warn about it and continue. - */ - if (dst_root == &cgrp_dfl_root) { - if (cgrp_dfl_visible) { - pr_warn("failed to create files (%d) while rebinding 0x%x to default root\n", - ret, ss_mask); - pr_warn("you may retry by moving them to a different hierarchy and unbinding\n"); - } - continue; - } - - do_each_subsys_mask(ss, tssid, tmp_ss_mask) { - if (tssid == ssid) - break; - css_clear_dir(cgroup_css(scgrp, ss), dcgrp); - } while_each_subsys_mask(); - return ret; - } while_each_subsys_mask(); - - /* - * Nothing can fail from this point on. Remove files for the - * removed subsystems and rebind each subsystem. - */ do_each_subsys_mask(ss, ssid, ss_mask) { struct cgroup_root *src_root = ss->root; struct cgroup *scgrp = &src_root->cgrp; @@ -1589,8 +1533,12 @@ static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask) WARN_ON(!css || cgroup_css(dcgrp, ss)); - css_clear_dir(css, NULL); + /* disable from the source */ + src_root->subsys_mask &= ~(1 << ssid); + WARN_ON(cgroup_apply_control(scgrp)); + cgroup_finalize_control(scgrp, 0); + /* rebind */ RCU_INIT_POINTER(scgrp->subsys[ssid], NULL); rcu_assign_pointer(dcgrp->subsys[ssid], css); ss->root = dst_root; @@ -1602,20 +1550,20 @@ static int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask) &dcgrp->e_csets[ss->id]); spin_unlock_bh(&css_set_lock); - src_root->subsys_mask &= ~(1 << ssid); - scgrp->subtree_control &= ~(1 << ssid); - cgroup_refresh_subtree_ss_mask(scgrp); - /* default hierarchy doesn't enable controllers by default */ dst_root->subsys_mask |= 1 << ssid; if (dst_root == &cgrp_dfl_root) { static_branch_enable(cgroup_subsys_on_dfl_key[ssid]); } else { dcgrp->subtree_control |= 1 << ssid; - cgroup_refresh_subtree_ss_mask(dcgrp); static_branch_disable(cgroup_subsys_on_dfl_key[ssid]); } + ret = cgroup_apply_control(dcgrp); + if (ret) + pr_warn("partial failure to rebind %s controller (err=%d)\n", + ss->name, ret); + if (ss->bind) ss->bind(css); } while_each_subsys_mask(); @@ -1807,7 +1755,7 @@ static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data) return -EINVAL; } - mutex_lock(&cgroup_mutex); + cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); /* See what subsystems are wanted */ ret = parse_cgroupfs_options(data, &opts); @@ -1840,7 +1788,7 @@ static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data) if (ret) goto out_unlock; - rebind_subsystems(&cgrp_dfl_root, removed_mask); + WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask)); if (opts.release_agent) { spin_lock(&release_agent_path_lock); @@ -1991,7 +1939,7 @@ static int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask) } root_cgrp->kn = root->kf_root->kn; - ret = css_populate_dir(&root_cgrp->self, NULL); + ret = css_populate_dir(&root_cgrp->self); if (ret) goto destroy_root; @@ -2070,7 +2018,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, goto out_mount; } - mutex_lock(&cgroup_mutex); + cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); /* First find the desired set of subsystems */ ret = parse_cgroupfs_options(data, &opts); @@ -3123,7 +3071,7 @@ static int cgroup_apply_control_enable(struct cgroup *cgrp) } if (cgroup_control(dsct) & (1 << ss->id)) { - ret = css_populate_dir(css, NULL); + ret = css_populate_dir(css); if (ret) return ret; } @@ -3162,10 +3110,11 @@ static void cgroup_apply_control_disable(struct cgroup *cgrp) if (!css) continue; - if (!(cgroup_ss_mask(dsct) & (1 << ss->id))) { + if (css->parent && + !(cgroup_ss_mask(dsct) & (1 << ss->id))) { kill_css(css); } else if (!(cgroup_control(dsct) & (1 << ss->id))) { - css_clear_dir(css, NULL); + css_clear_dir(css); if (ss->css_reset) ss->css_reset(css); } @@ -5159,7 +5108,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, if (ret) goto out_destroy; - ret = css_populate_dir(&cgrp->self, NULL); + ret = css_populate_dir(&cgrp->self); if (ret) goto out_destroy; @@ -5231,7 +5180,7 @@ static void kill_css(struct cgroup_subsys_state *css) * This must happen before css is disassociated with its cgroup. * See seq_css() for details. */ - css_clear_dir(css, NULL); + css_clear_dir(css); /* * Killing would put the base ref, but we need to keep it alive |