int krg_task_alloc(struct task_struct *task, struct pid *pid)
{
struct task_kddm_object *obj;
int nr = pid_knr(pid);
task->task_obj = NULL;
if (!task->nsproxy->krg_ns)
return 0;
#ifdef CONFIG_KRG_EPM
if (krg_current)
return 0;
#endif
/* Exclude kernel threads and local pids from using task kddm objects. */
/*
* At this stage, current->mm points the mm of the task being duplicated
* instead of the mm of task for which this struct is being allocated,
* but we only need to know whether it is NULL or not, which will be the
* same after copy_mm.
*/
if (!(nr & GLOBAL_PID_MASK) || !current->mm)
return 0;
obj = krg_task_create_writelock(nr);
if (!obj)
return -ENOMEM;
/* Set the link between task kddm object and tsk */
obj->task = task;
task->task_obj = obj;
return 0;
}
static void __put_pid(struct pid_kddm_object *obj)
{
struct pid *pid = obj->pid;
int nr = pid_knr(pid);
int may_put;
int grabbed = 0;
/* Try to avoid grabing the kddm object */
read_lock(&tasklist_lock);
spin_lock(&pid_kddm_lock);
may_put = may_put_pid(obj);
spin_unlock(&pid_kddm_lock);
if (!may_put)
goto release_work;
read_unlock(&tasklist_lock);
/* The pid seems to be unused locally. Have to check globally. */
/* Prevent pidmaps from changing host nodes. */
pidmap_map_read_lock();
fkddm_grab_object(kddm_def_ns, PID_KDDM_ID, nr,
KDDM_NO_FT_REQ | KDDM_DONT_KILL);
grabbed = 1;
read_lock(&tasklist_lock);
spin_lock(&pid_kddm_lock);
may_put = may_put_pid(obj);
if (may_put) {
obj->active = 0;
obj->node_count--;
if (obj->node_count)
/* Still used elsewhere */
may_put = 0;
}
spin_unlock(&pid_kddm_lock);
release_work:
spin_lock(&put_pid_wq_lock);
list_del_init(&obj->wq);
spin_unlock(&put_pid_wq_lock);
read_unlock(&tasklist_lock);
if (may_put) {
_kddm_remove_frozen_object(pid_kddm_set, nr);
pidmap_map_read_unlock();
} else if (grabbed) {
_kddm_put_object(pid_kddm_set, nr);
pidmap_map_read_unlock();
}
}
int export_pid(struct epm_action *action,
ghost_t *ghost, struct pid_link *link)
{
struct pid *pid = link->pid;
int nr = pid_knr(pid);
int retval;
if (!(nr & GLOBAL_PID_MASK))
return -EPERM;
if (ORIG_NODE(nr) == kerrighed_node_id && !pid->kddm_obj
&& action->type != EPM_CHECKPOINT) {
retval = create_pid_kddm_object(pid, 0);
if (retval)
return retval;
}
return ghost_write(ghost, &nr, sizeof(nr));
}
static int create_pid_kddm_object(struct pid *pid, int early)
{
int nr = pid_knr(pid);
struct pid_kddm_object *obj;
struct task_kddm_object *task_obj;
obj = _kddm_grab_object(pid_kddm_set, nr);
if (IS_ERR(obj)) {
_kddm_put_object(pid_kddm_set, nr);
return PTR_ERR(obj);
}
BUG_ON(!obj);
task_obj = krg_task_readlock(nr);
spin_lock(&pid_kddm_lock);
BUG_ON(early && pid->kddm_obj);
if (!pid->kddm_obj) {
obj->pid = pid;
obj->active = 1;
if (early)
obj->attach_pending = 1;
BUG_ON(obj->task_obj);
if (task_obj) {
BUG_ON(task_obj->pid_obj);
/*
* These rcu_assign_pointer are not really needed,
* but are cleaner :)
*/
rcu_assign_pointer(obj->task_obj, task_obj);
rcu_assign_pointer(obj->task_obj->pid_obj, obj);
}
pid->kddm_obj = obj;
}
BUG_ON(pid->kddm_obj != obj);
spin_unlock(&pid_kddm_lock);
krg_task_unlock(nr);
_kddm_put_object(pid_kddm_set, nr);
return 0;
}