.processes = ATOMIC_INIT(1),
.files = ATOMIC_INIT(0),
.sigpending = ATOMIC_INIT(0),
- .mq_bytes = 0,
.locked_shm = 0,
#ifdef CONFIG_KEYS
.uid_keyring = &root_user_keyring,
#endif
};
+/*
+ * These routines must be called with the uidhash spinlock held!
+ */
+static void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
+{
+ hlist_add_head(&up->uidhash_node, hashent);
+}
+
+static void uid_hash_remove(struct user_struct *up)
+{
+ hlist_del_init(&up->uidhash_node);
+}
+
+static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
+{
+ struct user_struct *user;
+ struct hlist_node *h;
+
+ hlist_for_each_entry(user, h, hashent, uidhash_node) {
+ if (user->uid == uid) {
+ atomic_inc(&user->__count);
+ return user;
+ }
+ }
+
+ return NULL;
+}
+
#ifdef CONFIG_FAIR_USER_SCHED
+
static void sched_destroy_user(struct user_struct *up)
{
sched_destroy_group(up->tg);
#endif /* CONFIG_FAIR_USER_SCHED */
-/*
- * These routines must be called with the uidhash spinlock held!
- */
-static inline void uid_hash_insert(struct user_struct *up, struct hlist_head *hashent)
+#if defined(CONFIG_FAIR_USER_SCHED) && defined(CONFIG_SYSFS)
+
+static struct kset *uids_kset; /* represents the /sys/kernel/uids/ directory */
+static DEFINE_MUTEX(uids_mutex);
+
+static inline void uids_mutex_lock(void)
{
- hlist_add_head(&up->uidhash_node, hashent);
+ mutex_lock(&uids_mutex);
}
-static inline void uid_hash_remove(struct user_struct *up)
+static inline void uids_mutex_unlock(void)
{
- hlist_del_init(&up->uidhash_node);
+ mutex_unlock(&uids_mutex);
}
-static inline struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent)
+/* uid directory attributes */
+static ssize_t cpu_shares_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
{
- struct user_struct *user;
- struct hlist_node *h;
+ struct user_struct *up = container_of(kobj, struct user_struct, kobj);
- hlist_for_each_entry(user, h, hashent, uidhash_node) {
- if(user->uid == uid) {
- atomic_inc(&user->__count);
- return user;
- }
+ return sprintf(buf, "%lu\n", sched_group_shares(up->tg));
+}
+
+static ssize_t cpu_shares_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t size)
+{
+ struct user_struct *up = container_of(kobj, struct user_struct, kobj);
+ unsigned long shares;
+ int rc;
+
+ sscanf(buf, "%lu", &shares);
+
+ rc = sched_group_set_shares(up->tg, shares);
+
+ return (rc ? rc : size);
+}
+
+static struct kobj_attribute cpu_share_attr =
+ __ATTR(cpu_share, 0644, cpu_shares_show, cpu_shares_store);
+
+/* default attributes per uid directory */
+static struct attribute *uids_attributes[] = {
+ &cpu_share_attr.attr,
+ NULL
+};
+
+/* the lifetime of user_struct is not managed by the core (now) */
+static void uids_release(struct kobject *kobj)
+{
+ return;
+}
+
+static struct kobj_type uids_ktype = {
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_attrs = uids_attributes,
+ .release = uids_release,
+};
+
+/* create /sys/kernel/uids/<uid>/cpu_share file for this user */
+static int uids_user_create(struct user_struct *up)
+{
+ struct kobject *kobj = &up->kobj;
+ int error;
+
+ memset(kobj, 0, sizeof(struct kobject));
+ kobj->ktype = &uids_ktype;
+ kobj->kset = uids_kset;
+ kobject_init(kobj);
+ kobject_set_name(&up->kobj, "%d", up->uid);
+ error = kobject_add(kobj);
+ if (error)
+ goto done;
+
+ kobject_uevent(kobj, KOBJ_ADD);
+done:
+ return error;
+}
+
+/* create these entries in sysfs:
+ * "/sys/kernel/uids" directory
+ * "/sys/kernel/uids/0" directory (for root user)
+ * "/sys/kernel/uids/0/cpu_share" file (for root user)
+ */
+int __init uids_sysfs_init(void)
+{
+ uids_kset = kset_create_and_add("uids", NULL, &kernel_kset->kobj);
+ if (!uids_kset)
+ return -ENOMEM;
+
+ return uids_user_create(&root_user);
+}
+
+/* work function to remove sysfs directory for a user and free up
+ * corresponding structures.
+ */
+static void remove_user_sysfs_dir(struct work_struct *w)
+{
+ struct user_struct *up = container_of(w, struct user_struct, work);
+ unsigned long flags;
+ int remove_user = 0;
+
+ /* Make uid_hash_remove() + sysfs_remove_file() + kobject_del()
+ * atomic.
+ */
+ uids_mutex_lock();
+
+ local_irq_save(flags);
+
+ if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
+ uid_hash_remove(up);
+ remove_user = 1;
+ spin_unlock_irqrestore(&uidhash_lock, flags);
+ } else {
+ local_irq_restore(flags);
}
- return NULL;
+ if (!remove_user)
+ goto done;
+
+ kobject_uevent(&up->kobj, KOBJ_REMOVE);
+ kobject_del(&up->kobj);
+ kobject_put(&up->kobj);
+
+ sched_destroy_user(up);
+ key_put(up->uid_keyring);
+ key_put(up->session_keyring);
+ kmem_cache_free(uid_cachep, up);
+
+done:
+ uids_mutex_unlock();
+}
+
+/* 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.
+ */
+static inline void free_user(struct user_struct *up, unsigned long flags)
+{
+ /* restore back the count */
+ atomic_inc(&up->__count);
+ spin_unlock_irqrestore(&uidhash_lock, flags);
+
+ INIT_WORK(&up->work, remove_user_sysfs_dir);
+ schedule_work(&up->work);
}
+#else /* CONFIG_FAIR_USER_SCHED && CONFIG_SYSFS */
+
+int uids_sysfs_init(void) { return 0; }
+static inline int uids_user_create(struct user_struct *up) { return 0; }
+static inline void uids_mutex_lock(void) { }
+static inline void uids_mutex_unlock(void) { }
+
+/* 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.
+ */
+static inline void free_user(struct user_struct *up, unsigned long flags)
+{
+ uid_hash_remove(up);
+ spin_unlock_irqrestore(&uidhash_lock, flags);
+ sched_destroy_user(up);
+ key_put(up->uid_keyring);
+ key_put(up->session_keyring);
+ kmem_cache_free(uid_cachep, up);
+}
+
+#endif
+
/*
* Locate the user_struct for the passed UID. If found, take a ref on it. The
* caller must undo that ref with free_uid().
return;
local_irq_save(flags);
- if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
- uid_hash_remove(up);
- spin_unlock_irqrestore(&uidhash_lock, flags);
- sched_destroy_user(up);
- key_put(up->uid_keyring);
- key_put(up->session_keyring);
- kmem_cache_free(uid_cachep, up);
- } else {
+ if (atomic_dec_and_lock(&up->__count, &uidhash_lock))
+ free_user(up, flags);
+ else
local_irq_restore(flags);
- }
}
struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid)
struct hlist_head *hashent = uidhashentry(ns, uid);
struct user_struct *up;
+ /* Make uid_hash_find() + uids_user_create() + uid_hash_insert()
+ * atomic.
+ */
+ uids_mutex_lock();
+
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
spin_unlock_irq(&uidhash_lock);
struct user_struct *new;
new = kmem_cache_alloc(uid_cachep, GFP_KERNEL);
- if (!new)
+ if (!new) {
+ uids_mutex_unlock();
return NULL;
+ }
+
new->uid = uid;
atomic_set(&new->__count, 1);
atomic_set(&new->processes, 0);
atomic_set(&new->inotify_watches, 0);
atomic_set(&new->inotify_devs, 0);
#endif
-
+#ifdef CONFIG_POSIX_MQUEUE
new->mq_bytes = 0;
+#endif
new->locked_shm = 0;
if (alloc_uid_keyring(new, current) < 0) {
kmem_cache_free(uid_cachep, new);
+ uids_mutex_unlock();
return NULL;
}
key_put(new->uid_keyring);
key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);
+ uids_mutex_unlock();
+ return NULL;
+ }
+
+ if (uids_user_create(new)) {
+ sched_destroy_user(new);
+ key_put(new->uid_keyring);
+ key_put(new->session_keyring);
+ kmem_cache_free(uid_cachep, new);
+ uids_mutex_unlock();
return NULL;
}
spin_lock_irq(&uidhash_lock);
up = uid_hash_find(uid, hashent);
if (up) {
- sched_destroy_user(new);
+ /* This case is not possible when CONFIG_FAIR_USER_SCHED
+ * is defined, since we serialize alloc_uid() using
+ * uids_mutex. Hence no need to call
+ * sched_destroy_user() or remove_user_sysfs_dir().
+ */
key_put(new->uid_keyring);
key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);
spin_unlock_irq(&uidhash_lock);
}
+
+ uids_mutex_unlock();
+
return up;
}
projects / linux-2.6-omap-h63xx.git / blobdiff