void free_ipc_ns(struct kref *kref)
{
struct ipc_namespace *ns;
ns = container_of(kref, struct ipc_namespace, kref);
/*
* Unregistering the hotplug notifier at the beginning guarantees
* that the ipc namespace won't be freed while we are inside the
* callback routine. Since the blocking_notifier_chain_XXX routines
* hold a rw lock on the notifier list, unregister_ipcns_notifier()
* won't take the rw lock before blocking_notifier_call_chain() has
* released the rd lock.
*/
unregister_ipcns_notifier(ns);
sem_exit_ns(ns);
msg_exit_ns(ns);
shm_exit_ns(ns);
kfree(ns);
atomic_dec(&nr_ipc_ns);
/*
* Do the ipcns removal notification after decrementing nr_ipc_ns in
* order to have a correct value when recomputing msgmni.
*/
ipcns_notify(IPCNS_REMOVED);
}
static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,
struct ipc_namespace *old_ns)
{
struct ipc_namespace *ns;
int err;
ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
if (ns == NULL)
return ERR_PTR(-ENOMEM);
atomic_set(&ns->count, 1);
err = mq_init_ns(ns);
if (err) {
kfree(ns);
return ERR_PTR(err);
}
atomic_inc(&nr_ipc_ns);
sem_init_ns(ns);
msg_init_ns(ns);
shm_init_ns(ns);
/*
* msgmni has already been computed for the new ipc ns.
* Thus, do the ipcns creation notification before registering that
* new ipcns in the chain.
*/
ipcns_notify(IPCNS_CREATED);
register_ipcns_notifier(ns);
ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
return ns;
}
static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
{
struct ipc_namespace *ns;
ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
if (ns == NULL)
return ERR_PTR(-ENOMEM);
atomic_inc(&nr_ipc_ns);
sem_init_ns(ns);
msg_init_ns(ns);
shm_init_ns(ns);
/*
* msgmni has already been computed for the new ipc ns.
* Thus, do the ipcns creation notification before registering that
* new ipcns in the chain.
*/
ipcns_notify(IPCNS_CREATED);
register_ipcns_notifier(ns);
kref_init(&ns->kref);
return ns;
}
static void ipc_memory_notifier(struct work_struct *work)
{
ipcns_notify(IPCNS_MEMCHANGED);
}
