diff options
Diffstat (limited to 'kernel/pid.c')
| -rw-r--r-- | kernel/pid.c | 75 |
1 files changed, 50 insertions, 25 deletions
diff --git a/kernel/pid.c b/kernel/pid.c index aebd4f5aaf41..de9af600006f 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -1,8 +1,8 @@ /* * Generic pidhash and scalable, time-bounded PID allocator * - * (C) 2002-2003 William Irwin, IBM - * (C) 2004 William Irwin, Oracle + * (C) 2002-2003 Nadia Yvette Chambers, IBM + * (C) 2004 Nadia Yvette Chambers, Oracle * (C) 2002-2004 Ingo Molnar, Red Hat * * pid-structures are backing objects for tasks sharing a given ID to chain @@ -36,6 +36,7 @@ #include <linux/pid_namespace.h> #include <linux/init_task.h> #include <linux/syscalls.h> +#include <linux/proc_fs.h> #define pid_hashfn(nr, ns) \ hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift) @@ -78,24 +79,11 @@ struct pid_namespace init_pid_ns = { .last_pid = 0, .level = 0, .child_reaper = &init_task, + .user_ns = &init_user_ns, + .proc_inum = PROC_PID_INIT_INO, }; EXPORT_SYMBOL_GPL(init_pid_ns); -int is_container_init(struct task_struct *tsk) -{ - int ret = 0; - struct pid *pid; - - rcu_read_lock(); - pid = task_pid(tsk); - if (pid != NULL && pid->numbers[pid->level].nr == 1) - ret = 1; - rcu_read_unlock(); - - return ret; -} -EXPORT_SYMBOL(is_container_init); - /* * Note: disable interrupts while the pidmap_lock is held as an * interrupt might come in and do read_lock(&tasklist_lock). @@ -269,8 +257,23 @@ void free_pid(struct pid *pid) unsigned long flags; spin_lock_irqsave(&pidmap_lock, flags); - for (i = 0; i <= pid->level; i++) - hlist_del_rcu(&pid->numbers[i].pid_chain); + for (i = 0; i <= pid->level; i++) { + struct upid *upid = pid->numbers + i; + struct pid_namespace *ns = upid->ns; + hlist_del_rcu(&upid->pid_chain); + switch(--ns->nr_hashed) { + case 1: + /* When all that is left in the pid namespace + * is the reaper wake up the reaper. The reaper + * may be sleeping in zap_pid_ns_processes(). + */ + wake_up_process(ns->child_reaper); + break; + case 0: + schedule_work(&ns->proc_work); + break; + } + } spin_unlock_irqrestore(&pidmap_lock, flags); for (i = 0; i <= pid->level; i++) @@ -292,6 +295,7 @@ struct pid *alloc_pid(struct pid_namespace *ns) goto out; tmp = ns; + pid->level = ns->level; for (i = ns->level; i >= 0; i--) { nr = alloc_pidmap(tmp); if (nr < 0) @@ -302,22 +306,32 @@ struct pid *alloc_pid(struct pid_namespace *ns) tmp = tmp->parent; } + if (unlikely(is_child_reaper(pid))) { + if (pid_ns_prepare_proc(ns)) + goto out_free; + } + get_pid_ns(ns); - pid->level = ns->level; atomic_set(&pid->count, 1); for (type = 0; type < PIDTYPE_MAX; ++type) INIT_HLIST_HEAD(&pid->tasks[type]); upid = pid->numbers + ns->level; spin_lock_irq(&pidmap_lock); - for ( ; upid >= pid->numbers; --upid) + if (!(ns->nr_hashed & PIDNS_HASH_ADDING)) + goto out_unlock; + for ( ; upid >= pid->numbers; --upid) { hlist_add_head_rcu(&upid->pid_chain, &pid_hash[pid_hashfn(upid->nr, upid->ns)]); + upid->ns->nr_hashed++; + } spin_unlock_irq(&pidmap_lock); out: return pid; +out_unlock: + spin_unlock(&pidmap_lock); out_free: while (++i <= ns->level) free_pidmap(pid->numbers + i); @@ -327,6 +341,13 @@ out_free: goto out; } +void disable_pid_allocation(struct pid_namespace *ns) +{ + spin_lock_irq(&pidmap_lock); + ns->nr_hashed &= ~PIDNS_HASH_ADDING; + spin_unlock_irq(&pidmap_lock); +} + struct pid *find_pid_ns(int nr, struct pid_namespace *ns) { struct hlist_node *elem; @@ -344,7 +365,7 @@ EXPORT_SYMBOL_GPL(find_pid_ns); struct pid *find_vpid(int nr) { - return find_pid_ns(nr, current->nsproxy->pid_ns); + return find_pid_ns(nr, task_active_pid_ns(current)); } EXPORT_SYMBOL_GPL(find_vpid); @@ -428,7 +449,7 @@ struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns) struct task_struct *find_task_by_vpid(pid_t vnr) { - return find_task_by_pid_ns(vnr, current->nsproxy->pid_ns); + return find_task_by_pid_ns(vnr, task_active_pid_ns(current)); } struct pid *get_task_pid(struct task_struct *task, enum pid_type type) @@ -483,7 +504,7 @@ EXPORT_SYMBOL_GPL(pid_nr_ns); pid_t pid_vnr(struct pid *pid) { - return pid_nr_ns(pid, current->nsproxy->pid_ns); + return pid_nr_ns(pid, task_active_pid_ns(current)); } EXPORT_SYMBOL_GPL(pid_vnr); @@ -494,7 +515,7 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, rcu_read_lock(); if (!ns) - ns = current->nsproxy->pid_ns; + ns = task_active_pid_ns(current); if (likely(pid_alive(task))) { if (type != PIDTYPE_PID) task = task->group_leader; @@ -558,6 +579,9 @@ void __init pidhash_init(void) void __init pidmap_init(void) { + /* Veryify no one has done anything silly */ + BUILD_BUG_ON(PID_MAX_LIMIT >= PIDNS_HASH_ADDING); + /* bump default and minimum pid_max based on number of cpus */ pid_max = min(pid_max_max, max_t(int, pid_max, PIDS_PER_CPU_DEFAULT * num_possible_cpus())); @@ -569,6 +593,7 @@ void __init pidmap_init(void) /* Reserve PID 0. We never call free_pidmap(0) */ set_bit(0, init_pid_ns.pidmap[0].page); atomic_dec(&init_pid_ns.pidmap[0].nr_free); + init_pid_ns.nr_hashed = PIDNS_HASH_ADDING; init_pid_ns.pid_cachep = KMEM_CACHE(pid, SLAB_HWCACHE_ALIGN | SLAB_PANIC); |