diff options
| -rw-r--r-- | include/linux/cgroup.h | 8 | ||||
| -rw-r--r-- | kernel/cgroup.c | 22 |
2 files changed, 13 insertions, 17 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index ab27001a2c4a..4c1eceb8c439 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -286,18 +286,12 @@ enum { struct cgroupfs_root { struct super_block *sb; - /* - * The bitmask of subsystems intended to be attached to this - * hierarchy - */ + /* The bitmask of subsystems attached to this hierarchy */ unsigned long subsys_mask; /* Unique id for this hierarchy. */ int hierarchy_id; - /* The bitmask of subsystems currently attached to this hierarchy */ - unsigned long actual_subsys_mask; - /* A list running through the attached subsystems */ struct list_head subsys_list; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 8f296b83b6a3..67fc953c816a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -986,17 +986,14 @@ static void cgroup_d_remove_dir(struct dentry *dentry) * returns an error, no reference counts are touched. */ static int rebind_subsystems(struct cgroupfs_root *root, - unsigned long final_subsys_mask) + unsigned long added_mask, unsigned removed_mask) { - unsigned long added_mask, removed_mask; struct cgroup *cgrp = &root->top_cgroup; int i; BUG_ON(!mutex_is_locked(&cgroup_mutex)); BUG_ON(!mutex_is_locked(&cgroup_root_mutex)); - removed_mask = root->actual_subsys_mask & ~final_subsys_mask; - added_mask = final_subsys_mask & ~root->actual_subsys_mask; /* Check that any added subsystems are currently free */ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { unsigned long bit = 1UL << i; @@ -1032,27 +1029,33 @@ static int rebind_subsystems(struct cgroupfs_root *root, BUG_ON(cgrp->subsys[i]); BUG_ON(!cgroup_dummy_top->subsys[i]); BUG_ON(cgroup_dummy_top->subsys[i]->cgroup != cgroup_dummy_top); + cgrp->subsys[i] = cgroup_dummy_top->subsys[i]; cgrp->subsys[i]->cgroup = cgrp; list_move(&ss->sibling, &root->subsys_list); ss->root = root; if (ss->bind) ss->bind(cgrp); + /* refcount was already taken, and we're keeping it */ + root->subsys_mask |= bit; } else if (bit & removed_mask) { /* We're removing this subsystem */ BUG_ON(ss == NULL); BUG_ON(cgrp->subsys[i] != cgroup_dummy_top->subsys[i]); BUG_ON(cgrp->subsys[i]->cgroup != cgrp); + if (ss->bind) ss->bind(cgroup_dummy_top); cgroup_dummy_top->subsys[i]->cgroup = cgroup_dummy_top; cgrp->subsys[i] = NULL; cgroup_subsys[i]->root = &cgroup_dummy_root; list_move(&ss->sibling, &cgroup_dummy_root.subsys_list); + /* subsystem is now free - drop reference on module */ module_put(ss->module); - } else if (bit & final_subsys_mask) { + root->subsys_mask &= ~bit; + } else if (bit & root->subsys_mask) { /* Subsystem state should already exist */ BUG_ON(ss == NULL); BUG_ON(!cgrp->subsys[i]); @@ -1069,7 +1072,6 @@ static int rebind_subsystems(struct cgroupfs_root *root, BUG_ON(cgrp->subsys[i]); } } - root->subsys_mask = root->actual_subsys_mask = final_subsys_mask; return 0; } @@ -1343,7 +1345,7 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data) if (ret) goto out_unlock; - if (opts.subsys_mask != root->actual_subsys_mask || opts.release_agent) + if (opts.subsys_mask != root->subsys_mask || opts.release_agent) pr_warning("cgroup: option changes via remount are deprecated (pid=%d comm=%s)\n", task_tgid_nr(current), current->comm); @@ -1365,7 +1367,7 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data) */ cgroup_clear_directory(cgrp->dentry, false, removed_mask); - ret = rebind_subsystems(root, opts.subsys_mask); + ret = rebind_subsystems(root, added_mask, removed_mask); if (ret) { /* rebind_subsystems failed, re-populate the removed files */ cgroup_populate_dir(cgrp, false, removed_mask); @@ -1634,7 +1636,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, if (ret) goto unlock_drop; - ret = rebind_subsystems(root, root->subsys_mask); + ret = rebind_subsystems(root, root->subsys_mask, 0); if (ret == -EBUSY) { free_cgrp_cset_links(&tmp_links); goto unlock_drop; @@ -1727,7 +1729,7 @@ static void cgroup_kill_sb(struct super_block *sb) { mutex_lock(&cgroup_root_mutex); /* Rebind all subsystems back to the default hierarchy */ - ret = rebind_subsystems(root, 0); + ret = rebind_subsystems(root, 0, root->subsys_mask); /* Shouldn't be able to fail ... */ BUG_ON(ret); |