[PATCH 5/8] user: Use generic ns_common::count

Kirill Tkhai
2020-08-03T10:16:41Z

Convert user namespace to use generic counter.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
---
include/linux/user_namespace.h | 5 ++---
kernel/user.c | 2 +-
kernel/user_namespace.c | 4 ++--
3 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 6ef1c7109fc4..64cf8ebdc4ec 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -57,7 +57,6 @@ struct user_namespace {
struct uid_gid_map uid_map;
struct uid_gid_map gid_map;
struct uid_gid_map projid_map;
- atomic_t count;
struct user_namespace *parent;
int level;
kuid_t owner;
@@ -109,7 +108,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
{
if (ns)
- atomic_inc(&ns->count);
+ refcount_inc(&ns->ns.count);
return ns;
}

@@ -119,7 +118,7 @@ extern void __put_user_ns(struct user_namespace *ns);

static inline void put_user_ns(struct user_namespace *ns)
{
- if (ns && atomic_dec_and_test(&ns->count))
+ if (ns && refcount_dec_and_test(&ns->ns.count))
__put_user_ns(ns);
}

diff --git a/kernel/user.c b/kernel/user.c
index b1635d94a1f2..a2478cddf536 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -55,7 +55,7 @@ struct user_namespace init_user_ns = {
},
},
},
- .count = ATOMIC_INIT(3),
+ .ns.count = REFCOUNT_INIT(3),
.owner = GLOBAL_ROOT_UID,
.group = GLOBAL_ROOT_GID,
.ns.inum = PROC_USER_INIT_INO,
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 87804e0371fe..7c2bbe8f3e45 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -111,7 +111,7 @@ int create_user_ns(struct cred *new)
goto fail_free;
ns->ns.ops = &userns_operations;

- atomic_set(&ns->count, 1);
+ refcount_set(&ns->ns.count, 1);
/* Leave the new->user_ns reference with the new user namespace. */
ns->parent = parent_ns;
ns->level = parent_ns->level + 1;
@@ -197,7 +197,7 @@ static void free_user_ns(struct work_struct *work)
kmem_cache_free(user_ns_cachep, ns);
dec_user_namespaces(ucounts);
ns = parent;
- } while (atomic_dec_and_test(&parent->count));
+ } while (refcount_dec_and_test(&parent->ns.count));
}

void __put_user_ns(struct user_namespace *ns)