fs/epoll: use a per-cpu counter for user's watches count

[linux-2.6-microblaze.git] / kernel / user.c

diff --git a/kernel/user.c b/kernel/user.c
index c82399c..e2cf8c2 100644 (file)
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -129,6 +129,22 @@ static struct user_struct *uid_hash_find(kuid_t uid, struct hlist_head *hashent)
        return NULL;
 }
 
        return NULL;
 }
 

+static int user_epoll_alloc(struct user_struct *up)
+{
+#ifdef CONFIG_EPOLL
+       return percpu_counter_init(&up->epoll_watches, 0, GFP_KERNEL);
+#else
+       return 0;
+#endif
+}
+
+static void user_epoll_free(struct user_struct *up)
+{
+#ifdef CONFIG_EPOLL
+       percpu_counter_destroy(&up->epoll_watches);
+#endif
+}
+

 /* IRQs are disabled and uidhash_lock is held upon function entry.
  * IRQ state (as stored in flags) is restored and uidhash_lock released
  * upon function exit.
 /* IRQs are disabled and uidhash_lock is held upon function entry.
  * IRQ state (as stored in flags) is restored and uidhash_lock released
  * upon function exit.


@@ -138,6 +154,7 @@ static void free_user(struct user_struct *up, unsigned long flags)
 {
        uid_hash_remove(up);
        spin_unlock_irqrestore(&uidhash_lock, flags);
 {
        uid_hash_remove(up);
        spin_unlock_irqrestore(&uidhash_lock, flags);

+       user_epoll_free(up);

        kmem_cache_free(uid_cachep, up);
 }
 
        kmem_cache_free(uid_cachep, up);
 }
 


@@ -185,6 +202,10 @@ struct user_struct *alloc_uid(kuid_t uid)
 
                new->uid = uid;
                refcount_set(&new->__count, 1);
 
                new->uid = uid;
                refcount_set(&new->__count, 1);

+               if (user_epoll_alloc(new)) {
+                       kmem_cache_free(uid_cachep, new);
+                       return NULL;
+               }

                ratelimit_state_init(&new->ratelimit, HZ, 100);
                ratelimit_set_flags(&new->ratelimit, RATELIMIT_MSG_ON_RELEASE);
 
                ratelimit_state_init(&new->ratelimit, HZ, 100);
                ratelimit_set_flags(&new->ratelimit, RATELIMIT_MSG_ON_RELEASE);
 


@@ -195,6 +216,7 @@ struct user_struct *alloc_uid(kuid_t uid)
                spin_lock_irq(&uidhash_lock);
                up = uid_hash_find(uid, hashent);
                if (up) {
                spin_lock_irq(&uidhash_lock);
                up = uid_hash_find(uid, hashent);
                if (up) {

+                       user_epoll_free(new);

                        kmem_cache_free(uid_cachep, new);
                } else {
                        uid_hash_insert(new, hashent);
                        kmem_cache_free(uid_cachep, new);
                } else {
                        uid_hash_insert(new, hashent);


@@ -216,6 +238,9 @@ static int __init uid_cache_init(void)
        for(n = 0; n < UIDHASH_SZ; ++n)
                INIT_HLIST_HEAD(uidhash_table + n);
 
        for(n = 0; n < UIDHASH_SZ; ++n)
                INIT_HLIST_HEAD(uidhash_table + n);
 

+       if (user_epoll_alloc(&root_user))
+               panic("root_user epoll percpu counter alloc failed");
+

        /* Insert the root user immediately (init already runs as root) */
        spin_lock_irq(&uidhash_lock);
        uid_hash_insert(&root_user, uidhashentry(GLOBAL_ROOT_UID));
        /* Insert the root user immediately (init already runs as root) */
        spin_lock_irq(&uidhash_lock);
        uid_hash_insert(&root_user, uidhashentry(GLOBAL_ROOT_UID));