[PATCH 1/8] ns: Add common refcount into ns_common add use it as counter for net_ns

Kirill Tkhai
2020-08-03T10:16:20Z

Currently, every type of namespaces has its own counter,
which is stored in ns-specific part. Say, @net has
struct net::count, @pid has struct pid_namespace::kref, etc.

This patchset introduces unified counter for all types
of namespaces, and converts net namespace to use it first.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
---
include/linux/ns_common.h | 3 +++
include/net/net_namespace.h | 11 ++++-------
net/core/net-sysfs.c | 6 +++---
net/core/net_namespace.c | 6 +++---
net/ipv4/inet_timewait_sock.c | 4 ++--
net/ipv4/tcp_metrics.c | 2 +-
6 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index 5fbc4000358f..0f1d024bd958 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h
@@ -2,12 +2,15 @@
#ifndef _LINUX_NS_COMMON_H
#define _LINUX_NS_COMMON_H

+#include <linux/refcount.h>
+
struct proc_ns_operations;

struct ns_common {
atomic_long_t stashed;
const struct proc_ns_operations *ops;
unsigned int inum;
+ refcount_t count;
};

#endif
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 2ee5901bec7a..cb4b33d7834b 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -60,9 +60,6 @@ struct net {
refcount_t passive; /* To decide when the network
* namespace should be freed.
*/
- refcount_t count; /* To decided when the network
- * namespace should be shut down.
- */
spinlock_t rules_mod_lock;

unsigned int dev_unreg_count;
@@ -245,7 +242,7 @@ void __put_net(struct net *net);

static inline struct net *get_net(struct net *net)
{
- refcount_inc(&net->count);
+ refcount_inc(&net->ns.count);
return net;
}

@@ -256,14 +253,14 @@ static inline struct net *maybe_get_net(struct net *net)
* exists. If the reference count is zero this
* function fails and returns NULL.
*/
- if (!refcount_inc_not_zero(&net->count))
+ if (!refcount_inc_not_zero(&net->ns.count))
net = NULL;
return net;
}

static inline void put_net(struct net *net)
{
- if (refcount_dec_and_test(&net->count))
+ if (refcount_dec_and_test(&net->ns.count))
__put_net(net);
}

@@ -275,7 +272,7 @@ int net_eq(const struct net *net1, const struct net *net2)

static inline int check_net(const struct net *net)
{
- return refcount_read(&net->count) != 0;
+ return refcount_read(&net->ns.count) != 0;
}

void net_drop_ns(void *);
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 9de33b594ff2..655a88b0071c 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1025,7 +1025,7 @@ net_rx_queue_update_kobjects(struct net_device *dev, int old_num, int new_num)
while (--i >= new_num) {
struct kobject *kobj = &dev->_rx[i].kobj;

- if (!refcount_read(&dev_net(dev)->count))
+ if (!refcount_read(&dev_net(dev)->ns.count))
kobj->uevent_suppress = 1;
if (dev->sysfs_rx_queue_group)
sysfs_remove_group(kobj, dev->sysfs_rx_queue_group);
@@ -1603,7 +1603,7 @@ netdev_queue_update_kobjects(struct net_device *dev, int old_num, int new_num)
while (--i >= new_num) {
struct netdev_queue *queue = dev->_tx + i;

- if (!refcount_read(&dev_net(dev)->count))
+ if (!refcount_read(&dev_net(dev)->ns.count))
queue->kobj.uevent_suppress = 1;
#ifdef CONFIG_BQL
sysfs_remove_group(&queue->kobj, &dql_group);
@@ -1850,7 +1850,7 @@ void netdev_unregister_kobject(struct net_device *ndev)
{
struct device *dev = &ndev->dev;

- if (!refcount_read(&dev_net(ndev)->count))
+ if (!refcount_read(&dev_net(ndev)->ns.count))
dev_set_uevent_suppress(dev, 1);

kobject_get(&dev->kobj);
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index dcd61aca343e..5f658cbedd34 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -44,7 +44,7 @@ static struct key_tag init_net_key_domain = { .usage = REFCOUNT_INIT(1) };
#endif

struct net init_net = {
- .count = REFCOUNT_INIT(1),
+ .ns.count = REFCOUNT_INIT(1),
.dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head),
#ifdef CONFIG_KEYS
.key_domain = &init_net_key_domain,
@@ -248,7 +248,7 @@ int peernet2id_alloc(struct net *net, struct net *peer, gfp_t gfp)
{
int id;

- if (refcount_read(&net->count) == 0)
+ if (refcount_read(&net->ns.count) == 0)
return NETNSA_NSID_NOT_ASSIGNED;

spin_lock(&net->nsid_lock);
@@ -328,7 +328,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns)
int error = 0;
LIST_HEAD(net_exit_list);

- refcount_set(&net->count, 1);
+ refcount_set(&net->ns.count, 1);
refcount_set(&net->passive, 1);
get_random_bytes(&net->hash_mix, sizeof(u32));
net->dev_base_seq = 1;
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index c411c87ae865..437afe392e66 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -272,14 +272,14 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
continue;
tw = inet_twsk(sk);
if ((tw->tw_family != family) ||
- refcount_read(&twsk_net(tw)->count))
+ refcount_read(&twsk_net(tw)->ns.count))
continue;

if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))
continue;

if (unlikely((tw->tw_family != family) ||
- refcount_read(&twsk_net(tw)->count))) {
+ refcount_read(&twsk_net(tw)->ns.count))) {
inet_twsk_put(tw);
goto restart;
}
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 279db8822439..39710c417565 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -887,7 +887,7 @@ static void tcp_metrics_flush_all(struct net *net)
pp = &hb->chain;
for (tm = deref_locked(*pp); tm; tm = deref_locked(*pp)) {
match = net ? net_eq(tm_net(tm), net) :
- !refcount_read(&tm_net(tm)->count);
+ !refcount_read(&tm_net(tm)->ns.count);
if (match) {
*pp = tm->tcpm_next;
kfree_rcu(tm, rcu_head);