summaryrefslogtreecommitdiff
path: root/include/linux/user_namespace.h
diff options
context:
space:
mode:
authorKirill Tkhai <ktkhai@virtuozzo.com>2020-08-03 13:16:37 +0300
committerChristian Brauner <christian.brauner@ubuntu.com>2020-08-19 15:14:12 +0300
commit265cbd62e034cb09a9da7cbff9072c8082f8df65 (patch)
tree7098de3c422e22f5eb1c0dee45466a370b8a0b95 /include/linux/user_namespace.h
parent8eb71d95f34a009cc22084e05e78eb9686f7ea28 (diff)
downloadlinux-265cbd62e034cb09a9da7cbff9072c8082f8df65.tar.xz
user: Use generic ns_common::count
Switch over user namespaces to use the newly introduced common lifetime counter. Currently every namespace type has its own lifetime counter which is stored in the specific namespace struct. The lifetime counters are used identically for all namespaces types. Namespaces may of course have additional unrelated counters and these are not altered. This introduces a common lifetime counter into struct ns_common. The ns_common struct encompasses information that all namespaces share. That should include the lifetime counter since its common for all of them. It also allows us to unify the type of the counters across all namespaces. Most of them use refcount_t but one uses atomic_t and at least one uses kref. Especially the last one doesn't make much sense since it's just a wrapper around refcount_t since 2016 and actually complicates cleanup operations by having to use container_of() to cast the correct namespace struct out of struct ns_common. Having the lifetime counter for the namespaces in one place reduces maintenance cost. Not just because after switching all namespaces over we will have removed more code than we added but also because the logic is more easily understandable and we indicate to the user that the basic lifetime requirements for all namespaces are currently identical. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Link: https://lore.kernel.org/r/159644979754.604812.601625186726406922.stgit@localhost.localdomain Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Diffstat (limited to 'include/linux/user_namespace.h')
-rw-r--r--include/linux/user_namespace.h5
1 files changed, 2 insertions, 3 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);
}