On Thu, Jul 30, 2020 at 02:59:31PM +0300, Kirill Tkhai wrote:
> Convert uts namespace to use generic counter instead of kref.
>
> Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
> ---
(sidenote: given that kref is implemented on top of refcount_t I wonder
whether we shouldn't just slowly convert all places where kref is used
to refcount_t and remove the kref api.)
Looks good!
Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> include/linux/utsname.h | 9 ++++-----
> init/version.c | 2 +-
> kernel/utsname.c | 7 ++-----
> 3 files changed, 7 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/utsname.h b/include/linux/utsname.h
> index 44429d9142ca..2b1737c9b244 100644
> --- a/include/linux/utsname.h
> +++ b/include/linux/utsname.h
> @@ -4,7 +4,6 @@
>
>
> #include <linux/sched.h>
> -#include <linux/kref.h>
> #include <linux/nsproxy.h>
> #include <linux/ns_common.h>
> #include <linux/err.h>
> @@ -22,7 +21,6 @@ struct user_namespace;
> extern struct user_namespace init_user_ns;
>
> struct uts_namespace {
> - struct kref kref;
> struct new_utsname name;
> struct user_namespace *user_ns;
> struct ucounts *ucounts;
> @@ -33,16 +31,17 @@ extern struct uts_namespace init_uts_ns;
> #ifdef CONFIG_UTS_NS
> static inline void get_uts_ns(struct uts_namespace *ns)
> {
> - kref_get(&ns->kref);
> + refcount_inc(&ns->ns.count);
> }
>
> extern struct uts_namespace *copy_utsname(unsigned long flags,
> struct user_namespace *user_ns, struct uts_namespace *old_ns);
> -extern void free_uts_ns(struct kref *kref);
> +extern void free_uts_ns(struct uts_namespace *ns);
>
> static inline void put_uts_ns(struct uts_namespace *ns)
> {
> - kref_put(&ns->kref, free_uts_ns);
> + if (refcount_dec_and_test(&ns->ns.count))
> + free_uts_ns(ns);
> }
>
> void uts_ns_init(void);
> diff --git a/init/version.c b/init/version.c
> index cba341161b58..80d2b7566b39 100644
> --- a/init/version.c
> +++ b/init/version.c
> @@ -25,7 +25,7 @@ int version_string(LINUX_VERSION_CODE);
> #endif
>
> struct uts_namespace init_uts_ns = {
> - .kref = KREF_INIT(2),
> + .ns.count = REFCOUNT_INIT(2),
> .name = {
> .sysname = UTS_SYSNAME,
> .nodename = UTS_NODENAME,
> diff --git a/kernel/utsname.c b/kernel/utsname.c
> index e488d0e2ab45..b1ac3ca870f2 100644
> --- a/kernel/utsname.c
> +++ b/kernel/utsname.c
> @@ -33,7 +33,7 @@ static struct uts_namespace *create_uts_ns(void)
>
> uts_ns = kmem_cache_alloc(uts_ns_cache, GFP_KERNEL);
> if (uts_ns)
> - kref_init(&uts_ns->kref);
> + refcount_set(&uts_ns->ns.count, 1);
> return uts_ns;
> }
>
> @@ -103,11 +103,8 @@ struct uts_namespace *copy_utsname(unsigned long flags,
> return new_ns;
> }
>
> -void free_uts_ns(struct kref *kref)
> +void free_uts_ns(struct uts_namespace *ns)
> {
> - struct uts_namespace *ns;
> -
> - ns = container_of(kref, struct uts_namespace, kref);
> dec_uts_namespaces(ns->ucounts);
> put_user_ns(ns->user_ns);
> ns_free_inum(&ns->ns);
>
>
