1 files changed, 12 insertions, 64 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2097684cf194..79818507e444 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -822,7 +822,7 @@ EXPORT_SYMBOL_GPL(cgroup_unlock);
  */
 
 static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
-static struct dentry *cgroup_lookup(struct inode *, struct dentry *, struct nameidata *);
+static struct dentry *cgroup_lookup(struct inode *, struct dentry *, unsigned int);
 static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
 static int cgroup_populate_dir(struct cgroup *cgrp);
 static const struct inode_operations cgroup_dir_inode_operations;
@@ -901,13 +901,10 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode)
                 mutex_unlock(&cgroup_mutex);
 
                 /*
-                 * We want to drop the active superblock reference from the
-                 * cgroup creation after all the dentry refs are gone -
-                 * kill_sb gets mighty unhappy otherwise.  Mark
-                 * dentry->d_fsdata with cgroup_diput() to tell
-                 * cgroup_d_release() to call deactivate_super().
+                 * Drop the active superblock reference that we took when we
+                 * created the cgroup
                  */
-                dentry->d_fsdata = cgroup_diput;
+                deactivate_super(cgrp->root->sb);
 
                 /*
                  * if we're getting rid of the cgroup, refcount should ensure
@@ -933,13 +930,6 @@ static int cgroup_delete(const struct dentry *d)
         return 1;
 }
 
-static void cgroup_d_release(struct dentry *dentry)
-{
-        /* did cgroup_diput() tell me to deactivate super? */
-        if (dentry->d_fsdata == cgroup_diput)
-                deactivate_super(dentry->d_sb);
-}
-
 static void remove_dir(struct dentry *d)
 {
         struct dentry *parent = dget(d->d_parent);
@@ -964,7 +954,7 @@ static int cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft)
 
                 dget(d);
                 d_delete(d);
-                simple_unlink(d->d_inode, d);
+                simple_unlink(cgrp->dentry->d_inode, d);
                 list_del_init(&cfe->node);
                 dput(d);
 
@@ -1078,28 +1068,24 @@ static int rebind_subsystems(struct cgroupfs_root *root,
                         BUG_ON(cgrp->subsys[i]);
                         BUG_ON(!dummytop->subsys[i]);
                         BUG_ON(dummytop->subsys[i]->cgroup != dummytop);
-                        mutex_lock(&ss->hierarchy_mutex);
                         cgrp->subsys[i] = dummytop->subsys[i];
                         cgrp->subsys[i]->cgroup = cgrp;
                         list_move(&ss->sibling, &root->subsys_list);
                         ss->root = root;
                         if (ss->bind)
                                 ss->bind(cgrp);
-                        mutex_unlock(&ss->hierarchy_mutex);
                         /* refcount was already taken, and we're keeping it */
                 } else if (bit & removed_bits) {
                         /* We're removing this subsystem */
                         BUG_ON(ss == NULL);
                         BUG_ON(cgrp->subsys[i] != dummytop->subsys[i]);
                         BUG_ON(cgrp->subsys[i]->cgroup != cgrp);
-                        mutex_lock(&ss->hierarchy_mutex);
                         if (ss->bind)
                                 ss->bind(dummytop);
                         dummytop->subsys[i]->cgroup = dummytop;
                         cgrp->subsys[i] = NULL;
                         subsys[i]->root = &rootnode;
                         list_move(&ss->sibling, &rootnode.subsys_list);
-                        mutex_unlock(&ss->hierarchy_mutex);
                         /* subsystem is now free - drop reference on module */
                         module_put(ss->module);
                 } else if (bit & final_bits) {
@@ -1547,7 +1533,6 @@ static int cgroup_get_rootdir(struct super_block *sb)
         static const struct dentry_operations cgroup_dops = {
                 .d_iput = cgroup_diput,
                 .d_delete = cgroup_delete,
-                .d_release = cgroup_d_release,
         };
 
         struct inode *inode =
@@ -1598,7 +1583,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
         opts.new_root = new_root;
 
         /* Locate an existing or new sb for this hierarchy */
-        sb = sget(fs_type, cgroup_test_super, cgroup_set_super, &opts);
+        sb = sget(fs_type, cgroup_test_super, cgroup_set_super, 0, &opts);
         if (IS_ERR(sb)) {
                 ret = PTR_ERR(sb);
                 cgroup_drop_root(opts.new_root);
@@ -2581,7 +2566,7 @@ static const struct inode_operations cgroup_dir_inode_operations = {
         .rename = cgroup_rename,
 };
 
-static struct dentry *cgroup_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+static struct dentry *cgroup_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
 {
         if (dentry->d_name.len > NAME_MAX)
                 return ERR_PTR(-ENAMETOOLONG);
@@ -3894,8 +3879,12 @@ static void css_dput_fn(struct work_struct *work)
 {
         struct cgroup_subsys_state *css =
                 container_of(work, struct cgroup_subsys_state, dput_work);
+        struct dentry *dentry = css->cgroup->dentry;
+        struct super_block *sb = dentry->d_sb;
 
-        dput(css->cgroup->dentry);
+        atomic_inc(&sb->s_active);
+        dput(dentry);
+        deactivate_super(sb);
 }
 
 static void init_cgroup_css(struct cgroup_subsys_state *css,
@@ -3922,37 +3911,6 @@ static void init_cgroup_css(struct cgroup_subsys_state *css,
                 set_bit(CSS_CLEAR_CSS_REFS, &css->flags);
 }
 
-static void cgroup_lock_hierarchy(struct cgroupfs_root *root)
-{
-        /* We need to take each hierarchy_mutex in a consistent order */
-        int i;
-
-        /*
-         * No worry about a race with rebind_subsystems that might mess up the
-         * locking order, since both parties are under cgroup_mutex.
-         */
-        for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
-                struct cgroup_subsys *ss = subsys[i];
-                if (ss == NULL)
-                        continue;
-                if (ss->root == root)
-                        mutex_lock(&ss->hierarchy_mutex);
-        }
-}
-
-static void cgroup_unlock_hierarchy(struct cgroupfs_root *root)
-{
-        int i;
-
-        for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
-                struct cgroup_subsys *ss = subsys[i];
-                if (ss == NULL)
-                        continue;
-                if (ss->root == root)
-                        mutex_unlock(&ss->hierarchy_mutex);
-        }
-}
-
 /*
  * cgroup_create - create a cgroup
  * @parent: cgroup that will be parent of the new cgroup
@@ -4013,9 +3971,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
                         ss->post_clone(cgrp);
         }
 
-        cgroup_lock_hierarchy(root);
         list_add(&cgrp->sibling, &cgrp->parent->children);
-        cgroup_unlock_hierarchy(root);
         root->number_of_cgroups++;
 
         err = cgroup_create_dir(cgrp, dentry, mode);
@@ -4042,9 +3998,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 
  err_remove:
 
-        cgroup_lock_hierarchy(root);
         list_del(&cgrp->sibling);
-        cgroup_unlock_hierarchy(root);
         root->number_of_cgroups--;
 
  err_destroy:
@@ -4252,10 +4206,8 @@ again:
                 list_del_init(&cgrp->release_list);
         raw_spin_unlock(&release_list_lock);
 
-        cgroup_lock_hierarchy(cgrp->root);
         /* delete this cgroup from parent->children */
         list_del_init(&cgrp->sibling);
-        cgroup_unlock_hierarchy(cgrp->root);
 
         list_del_init(&cgrp->allcg_node);
 
@@ -4329,8 +4281,6 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
          * need to invoke fork callbacks here. */
         BUG_ON(!list_empty(&init_task.tasks));
 
-        mutex_init(&ss->hierarchy_mutex);
-        lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key);
         ss->active = 1;
 
         /* this function shouldn't be used with modular subsystems, since they
@@ -4457,8 +4407,6 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
         }
         write_unlock(&css_set_lock);
 
-        mutex_init(&ss->hierarchy_mutex);
-        lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key);
         ss->active = 1;
 
         /* success! */