diff options
| -rw-r--r-- | include/linux/user_namespace.h | 10 | ||||
| -rw-r--r-- | kernel/user.c | 4 | ||||
| -rw-r--r-- | kernel/user_namespace.c | 17 |
3 files changed, 15 insertions, 16 deletions
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index b9bd2e6..4ce0093 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -21,7 +21,7 @@ struct user_namespace { struct uid_gid_map uid_map; struct uid_gid_map gid_map; struct uid_gid_map projid_map; - struct kref kref; + atomic_t count; struct user_namespace *parent; kuid_t owner; kgid_t group; @@ -35,18 +35,18 @@ extern struct user_namespace init_user_ns; static inline struct user_namespace *get_user_ns(struct user_namespace *ns) { if (ns) - kref_get(&ns->kref); + atomic_inc(&ns->count); return ns; } extern int create_user_ns(struct cred *new); extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred); -extern void free_user_ns(struct kref *kref); +extern void free_user_ns(struct user_namespace *ns); static inline void put_user_ns(struct user_namespace *ns) { - if (ns) - kref_put(&ns->kref, free_user_ns); + if (ns && atomic_dec_and_test(&ns->count)) + free_user_ns(ns); } struct seq_operations; diff --git a/kernel/user.c b/kernel/user.c index 33acb5e..57ebfd4 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -47,9 +47,7 @@ struct user_namespace init_user_ns = { .count = 4294967295U, }, }, - .kref = { - .refcount = ATOMIC_INIT(3), - }, + .count = ATOMIC_INIT(3), .owner = GLOBAL_ROOT_UID, .group = GLOBAL_ROOT_GID, .proc_inum = PROC_USER_INIT_INO, diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 2b042c4..24f8ec3 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -78,7 +78,7 @@ int create_user_ns(struct cred *new) return ret; } - kref_init(&ns->kref); + atomic_set(&ns->count, 1); /* Leave the new->user_ns reference with the new user namespace. */ ns->parent = parent_ns; ns->owner = owner; @@ -104,15 +104,16 @@ int unshare_userns(unsigned long unshare_flags, struct cred **new_cred) return create_user_ns(cred); } -void free_user_ns(struct kref *kref) +void free_user_ns(struct user_namespace *ns) { - struct user_namespace *parent, *ns = - container_of(kref, struct user_namespace, kref); + struct user_namespace *parent; - parent = ns->parent; - proc_free_inum(ns->proc_inum); - kmem_cache_free(user_ns_cachep, ns); - put_user_ns(parent); + do { + parent = ns->parent; + proc_free_inum(ns->proc_inum); + kmem_cache_free(user_ns_cachep, ns); + ns = parent; + } while (atomic_dec_and_test(&parent->count)); } EXPORT_SYMBOL(free_user_ns); |
