[PATCH 4/8] pid: Use generic ns_common::count

Kirill Tkhai
2020-08-03T10:16:36Z

Convert pid namespace to use generic counter.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
---
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;
}
}