Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-flexiantxendom0-3.2.10.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c6877fe..ed64cca 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1472,7 +1472,6 @@ static int cgroup_get_rootdir(struct super_block *sb)
 
        struct inode *inode =
                cgroup_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR, sb);
-       struct dentry *dentry;
 
        if (!inode)
                return -ENOMEM;
@@ -1481,12 +1480,9 @@ static int cgroup_get_rootdir(struct super_block *sb)
        inode->i_op = &cgroup_dir_inode_operations;
        /* directories start off with i_nlink == 2 (for "." entry) */
        inc_nlink(inode);
-       dentry = d_alloc_root(inode);
-       if (!dentry) {
-               iput(inode);
+       sb->s_root = d_make_root(inode);
+       if (!sb->s_root)
                return -ENOMEM;
-       }
-       sb->s_root = dentry;
        /* for everything else we want ->d_op set */
        sb->s_d_op = &cgroup_dops;
        return 0;
@@ -1887,7 +1883,7 @@ static void cgroup_task_migrate(struct cgroup *cgrp, struct cgroup *oldcgrp,
  */
 int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
 {
-       int retval;
+       int retval = 0;
        struct cgroup_subsys *ss, *failed_ss = NULL;
        struct cgroup *oldcgrp;
        struct cgroupfs_root *root = cgrp->root;
@@ -4885,9 +4881,9 @@ void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css)
 
        rcu_assign_pointer(id->css, NULL);
        rcu_assign_pointer(css->id, NULL);
-       write_lock(&ss->id_lock);
+       spin_lock(&ss->id_lock);
        idr_remove(&ss->idr, id->id);
-       write_unlock(&ss->id_lock);
+       spin_unlock(&ss->id_lock);
        kfree_rcu(id, rcu_head);
 }
 EXPORT_SYMBOL_GPL(free_css_id);
@@ -4913,10 +4909,10 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth)
                error = -ENOMEM;
                goto err_out;
        }
-       write_lock(&ss->id_lock);
+       spin_lock(&ss->id_lock);
        /* Don't use 0. allocates an ID of 1-65535 */
        error = idr_get_new_above(&ss->idr, newid, 1, &myid);
-       write_unlock(&ss->id_lock);
+       spin_unlock(&ss->id_lock);
 
        /* Returns error when there are no free spaces for new ID.*/
        if (error) {
@@ -4931,9 +4927,9 @@ static struct css_id *get_new_cssid(struct cgroup_subsys *ss, int depth)
        return newid;
 remove_idr:
        error = -ENOSPC;
-       write_lock(&ss->id_lock);
+       spin_lock(&ss->id_lock);
        idr_remove(&ss->idr, myid);
-       write_unlock(&ss->id_lock);
+       spin_unlock(&ss->id_lock);
 err_out:
        kfree(newid);
        return ERR_PTR(error);
@@ -4945,7 +4941,7 @@ static int __init_or_module cgroup_init_idr(struct cgroup_subsys *ss,
 {
        struct css_id *newid;
 
-       rwlock_init(&ss->id_lock);
+       spin_lock_init(&ss->id_lock);
        idr_init(&ss->idr);
 
        newid = get_new_cssid(ss, 0);
@@ -5033,6 +5029,8 @@ css_get_next(struct cgroup_subsys *ss, int id,
                return NULL;
 
        BUG_ON(!ss->use_id);
+       WARN_ON_ONCE(!rcu_read_lock_held());
+
        /* fill start point for scan */
        tmpid = id;
        while (1) {
@@ -5040,10 +5038,7 @@ css_get_next(struct cgroup_subsys *ss, int id,
                 * scan next entry from bitmap(tree), tmpid is updated after
                 * idr_get_next().
                 */
-               read_lock(&ss->id_lock);
                tmp = idr_get_next(&ss->idr, &tmpid);
-               read_unlock(&ss->id_lock);
-
                if (!tmp)
                        break;
                if (tmp->depth >= depth && tmp->stack[depth] == rootid) {