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Message-ID: <20240729210801.16196-3-kuniyu@amazon.com>
Date: Mon, 29 Jul 2024 14:07:57 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net-next 2/6] net: Don't register pernet_operations if only one of id or size is specified.
We can allocate per-netns memory for struct pernet_operations by specifying
id and size.
register_pernet_operations() assigns an id to pernet_operations and later
ops_init() allocates the specified size of memory as net->gen->ptr[id].
If id is missing, no memory is allocated. If size is not specified,
pernet_operations just wastes an entry of net->gen->ptr[] for every netns.
net_generic is useful only when both id and size are specified, so let's
ensure that.
While we are at it, we add const to both fields.
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
include/net/net_namespace.h | 4 ++--
net/core/net_namespace.c | 12 ++++++++----
2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 20c34bd7a077..e67b483cc8bb 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -451,8 +451,8 @@ struct pernet_operations {
/* Following method is called with RTNL held. */
void (*exit_batch_rtnl)(struct list_head *net_exit_list,
struct list_head *dev_kill_list);
- unsigned int *id;
- size_t size;
+ unsigned int * const id;
+ const size_t size;
};
/*
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index 6a823ba906c6..1d164ae097a5 100644
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -125,7 +125,7 @@ static int ops_init(const struct pernet_operations *ops, struct net *net)
int err = -ENOMEM;
void *data = NULL;
- if (ops->id && ops->size) {
+ if (ops->id) {
data = kzalloc(ops->size, GFP_KERNEL);
if (!data)
goto out;
@@ -140,7 +140,7 @@ static int ops_init(const struct pernet_operations *ops, struct net *net)
if (!err)
return 0;
- if (ops->id && ops->size) {
+ if (ops->id) {
ng = rcu_dereference_protected(net->gen,
lockdep_is_held(&pernet_ops_rwsem));
ng->ptr[*ops->id] = NULL;
@@ -182,7 +182,8 @@ static void ops_free_list(const struct pernet_operations *ops,
struct list_head *net_exit_list)
{
struct net *net;
- if (ops->size && ops->id) {
+
+ if (ops->id) {
list_for_each_entry(net, net_exit_list, exit_list)
kfree(net_generic(net, *ops->id));
}
@@ -1244,7 +1245,7 @@ static int __register_pernet_operations(struct list_head *list,
LIST_HEAD(net_exit_list);
list_add_tail(&ops->list, list);
- if (ops->init || (ops->id && ops->size)) {
+ if (ops->init || ops->id) {
/* We held write locked pernet_ops_rwsem, and parallel
* setup_net() and cleanup_net() are not possible.
*/
@@ -1310,6 +1311,9 @@ static int register_pernet_operations(struct list_head *list,
{
int error;
+ if (WARN_ON((ops->id && !ops->size) || (!ops->id && ops->size)))
+ return -EINVAL;
+
if (ops->id) {
error = ida_alloc_min(&net_generic_ids, MIN_PERNET_OPS_ID,
GFP_KERNEL);
--
2.30.2
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