mm: remove cgroup_mm_owner_callbacks

[linux-2.6-omap-h63xx.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 8185a0f09594fd904ca2ab032dca27013708ff1c..f221446aa02da4d60b32bbc7a8a53354e155c11d 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -116,7 +116,6 @@ static int root_count;
  * be called.
  */
 static int need_forkexit_callback __read_mostly;
-static int need_mm_owner_callback __read_mostly;
 
 /* convenient tests for these bits */
 inline int cgroup_is_removed(const struct cgroup *cgrp)
@@ -571,9 +570,8 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)
 
        if (inode) {
                inode->i_mode = mode;
-               inode->i_uid = current->fsuid;
-               inode->i_gid = current->fsgid;
-               inode->i_blocks = 0;
+               inode->i_uid = current_fsuid();
+               inode->i_gid = current_fsgid();
                inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
                inode->i_mapping->backing_dev_info = &cgroup_backing_dev_info;
        }
@@ -1024,7 +1022,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
                if (ret == -EBUSY) {
                        mutex_unlock(&cgroup_mutex);
                        mutex_unlock(&inode->i_mutex);
-                       goto drop_new_super;
+                       goto free_cg_links;
                }
 
                /* EBUSY should be the only error here */
@@ -1073,10 +1071,11 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
 
        return simple_set_mnt(mnt, sb);
 
+ free_cg_links:
+       free_cg_links(&tmp_cg_links);
  drop_new_super:
        up_write(&sb->s_umount);
        deactivate_super(sb);
-       free_cg_links(&tmp_cg_links);
        return ret;
 }
 
@@ -1279,6 +1278,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
 static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
 {
        struct task_struct *tsk;
+       const struct cred *cred = current_cred(), *tcred;
        int ret;
 
        if (pid) {
@@ -1288,14 +1288,16 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid)
                        rcu_read_unlock();
                        return -ESRCH;
                }
-               get_task_struct(tsk);
-               rcu_read_unlock();
 
-               if ((current->euid) && (current->euid != tsk->uid)
-                   && (current->euid != tsk->suid)) {
-                       put_task_struct(tsk);
+               tcred = __task_cred(tsk);
+               if (cred->euid &&
+                   cred->euid != tcred->uid &&
+                   cred->euid != tcred->suid) {
+                       rcu_read_unlock();
                        return -EACCES;
                }
+               get_task_struct(tsk);
+               rcu_read_unlock();
        } else {
                tsk = current;
                get_task_struct(tsk);
@@ -2536,7 +2538,6 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
        init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id];
 
        need_forkexit_callback |= ss->fork || ss->exit;
-       need_mm_owner_callback |= !!ss->mm_owner_changed;
 
        /* At system boot, before all subsystems have been
         * registered, no tasks have been forked, so we don't
@@ -2786,37 +2787,6 @@ void cgroup_fork_callbacks(struct task_struct *child)
        }
 }
 
-#ifdef CONFIG_MM_OWNER
-/**
- * cgroup_mm_owner_callbacks - run callbacks when the mm->owner changes
- * @p: the new owner
- *
- * Called on every change to mm->owner. mm_init_owner() does not
- * invoke this routine, since it assigns the mm->owner the first time
- * and does not change it.
- *
- * The callbacks are invoked with mmap_sem held in read mode.
- */
-void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
-{
-       struct cgroup *oldcgrp, *newcgrp = NULL;
-
-       if (need_mm_owner_callback) {
-               int i;
-               for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
-                       struct cgroup_subsys *ss = subsys[i];
-                       oldcgrp = task_cgroup(old, ss->subsys_id);
-                       if (new)
-                               newcgrp = task_cgroup(new, ss->subsys_id);
-                       if (oldcgrp == newcgrp)
-                               continue;
-                       if (ss->mm_owner_changed)
-                               ss->mm_owner_changed(ss, oldcgrp, newcgrp, new);
-               }
-       }
-}
-#endif /* CONFIG_MM_OWNER */
-
 /**
  * cgroup_post_fork - called on a new task after adding it to the task list
  * @child: the task in question
@@ -2934,9 +2904,6 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
  again:
        root = subsys->root;
        if (root == &rootnode) {
-               printk(KERN_INFO
-                      "Not cloning cgroup for unused subsystem %s\n",
-                      subsys->name);
                mutex_unlock(&cgroup_mutex);
                return 0;
        }
@@ -2944,7 +2911,11 @@ int cgroup_clone(struct task_struct *tsk, struct cgroup_subsys *subsys,
        parent = task_cgroup(tsk, subsys->subsys_id);
 
        /* Pin the hierarchy */
-       atomic_inc(&parent->root->sb->s_active);
+       if (!atomic_inc_not_zero(&parent->root->sb->s_active)) {
+               /* We race with the final deactivate_super() */
+               mutex_unlock(&cgroup_mutex);
+               return 0;
+       }
 
        /* Keep the cgroup alive */
        get_css_set(cg);