On Thu, Jul 30, 2020 at 02:59:41PM +0300, Kirill Tkhai wrote:
> Convert pid namespace to use generic counter.
>
> Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
> ---
Looks good!
Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> include/linux/pid_namespace.h | 4 +---
> kernel/pid.c | 2 +-
> kernel/pid_namespace.c | 13 +++----------
> 3 files changed, 5 insertions(+), 14 deletions(-)
>
> diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
> index 5a5cb45ac57e..7c7e627503d2 100644
> --- a/include/linux/pid_namespace.h
> +++ b/include/linux/pid_namespace.h
> @@ -8,7 +8,6 @@
> #include <linux/workqueue.h>
> #include <linux/threads.h>
> #include <linux/nsproxy.h>
> -#include <linux/kref.h>
> #include <linux/ns_common.h>
> #include <linux/idr.h>
>
> @@ -18,7 +17,6 @@
> struct fs_pin;
>
> struct pid_namespace {
> - struct kref kref;
> struct idr idr;
> struct rcu_head rcu;
> unsigned int pid_allocated;
> @@ -43,7 +41,7 @@ extern struct pid_namespace init_pid_ns;
> static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
> {
> if (ns != &init_pid_ns)
> - kref_get(&ns->kref);
> + refcount_inc(&ns->ns.count);
> return ns;
> }
>
> diff --git a/kernel/pid.c b/kernel/pid.c
> index de9d29c41d77..3b9e67736ef4 100644
> --- a/kernel/pid.c
> +++ b/kernel/pid.c
> @@ -72,7 +72,7 @@ int pid_max_max = PID_MAX_LIMIT;
> * the scheme scales to up to 4 million PIDs, runtime.
> */
> struct pid_namespace init_pid_ns = {
> - .kref = KREF_INIT(2),
> + .ns.count = REFCOUNT_INIT(2),
> .idr = IDR_INIT(init_pid_ns.idr),
> .pid_allocated = PIDNS_ADDING,
> .level = 0,
> diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
> index 0e5ac162c3a8..d02dc1696edf 100644
> --- a/kernel/pid_namespace.c
> +++ b/kernel/pid_namespace.c
> @@ -102,7 +102,7 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
> goto out_free_idr;
> ns->ns.ops = &pidns_operations;
>
> - kref_init(&ns->kref);
> + refcount_set(&ns->ns.count, 1);
> ns->level = level;
> ns->parent = get_pid_ns(parent_pid_ns);
> ns->user_ns = get_user_ns(user_ns);
> @@ -148,22 +148,15 @@ struct pid_namespace *copy_pid_ns(unsigned long flags,
> return create_pid_namespace(user_ns, old_ns);
> }
>
> -static void free_pid_ns(struct kref *kref)
> -{
> - struct pid_namespace *ns;
> -
> - ns = container_of(kref, struct pid_namespace, kref);
> - destroy_pid_namespace(ns);
> -}
> -
> void put_pid_ns(struct pid_namespace *ns)
> {
> struct pid_namespace *parent;
>
> while (ns != &init_pid_ns) {
> parent = ns->parent;
> - if (!kref_put(&ns->kref, free_pid_ns))
> + if (!refcount_dec_and_test(&ns->ns.count))
> break;
> + destroy_pid_namespace(ns);
> ns = parent;
> }
> }
>
>
