pidns: Make the pidns proc mount/umount logic obvious.

[GitHub/exynos8895/android_kernel_samsung_universal8895.git] / kernel / pid.c

diff --git a/kernel/pid.c b/kernel/pid.c
index 3a5f238c1ca02ec74d1770dd359a137c1e98be6d..e957f8b091364b1f8e20196fceab6367d6cd2f0e 100644 (file)
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -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)
@@ -270,8 +271,12 @@ 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;
+               hlist_del_rcu(&upid->pid_chain);
+               if (--upid->ns->nr_hashed == 0)
+                       schedule_work(&upid->ns->proc_work);
+       }
        spin_unlock_irqrestore(&pidmap_lock, flags);
 
        for (i = 0; i <= pid->level; i++)
@@ -293,6 +298,7 @@ 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)
@@ -303,17 +309,23 @@ 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)
+       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:
@@ -570,6 +582,7 @@ 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 = 1;
 
        init_pid_ns.pid_cachep = KMEM_CACHE(pid,
                        SLAB_HWCACHE_ALIGN | SLAB_PANIC);