net: create netdev_nl_sock to wrap bindings list

No functional changes. Next patches will add more granular locking
to netdev_nl_sock.

Signed-off-by: Stanislav Fomichev <[e-mail]>
Reviewed-by: Mina Almasry <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

Documentation/netlink/specs/netdev.yaml

···
             - irq-suspend-timeout
 
 kernel-family:
-  headers: [ "linux/list.h"]
-  sock-priv: struct list_head
+  headers: [ "net/netdev_netlink.h"]
+  sock-priv: struct netdev_nl_sock
 
 mcast-groups:
   list:

include/net/netdev_netlink.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __NET_NETDEV_NETLINK_H
+#define __NET_NETDEV_NETLINK_H
+
+#include <linux/list.h>
+
+struct netdev_nl_sock {
+	struct list_head bindings;
+};
+
+#endif	/* __NET_NETDEV_NETLINK_H */

net/core/netdev-genl-gen.c

···
 #include "netdev-genl-gen.h"
 
 #include <uapi/linux/netdev.h>
-#include <linux/list.h>
+#include <net/netdev_netlink.h>
 
 /* Integer value ranges */
 static const struct netlink_range_validation netdev_a_page_pool_id_range = {
···
 	.n_split_ops	= ARRAY_SIZE(netdev_nl_ops),
 	.mcgrps		= netdev_nl_mcgrps,
 	.n_mcgrps	= ARRAY_SIZE(netdev_nl_mcgrps),
-	.sock_priv_size	= sizeof(struct list_head),
+	.sock_priv_size	= sizeof(struct netdev_nl_sock),
 	.sock_priv_init	= __netdev_nl_sock_priv_init,
 	.sock_priv_destroy = __netdev_nl_sock_priv_destroy,
 };

net/core/netdev-genl-gen.h

···
 #include <net/genetlink.h>
 
 #include <uapi/linux/netdev.h>
-#include <linux/list.h>
+#include <net/netdev_netlink.h>
 
 /* Common nested types */
 extern const struct nla_policy netdev_page_pool_info_nl_policy[NETDEV_A_PAGE_POOL_IFINDEX + 1];
···
 
 extern struct genl_family netdev_nl_family;
 
-void netdev_nl_sock_priv_init(struct list_head *priv);
-void netdev_nl_sock_priv_destroy(struct list_head *priv);
+void netdev_nl_sock_priv_init(struct netdev_nl_sock *priv);
+void netdev_nl_sock_priv_destroy(struct netdev_nl_sock *priv);
 
 #endif /* _LINUX_NETDEV_GEN_H */

net/core/netdev-genl.c

···
 {
 	struct nlattr *tb[ARRAY_SIZE(netdev_queue_id_nl_policy)];
 	struct net_devmem_dmabuf_binding *binding;
-	struct list_head *sock_binding_list;
 	u32 ifindex, dmabuf_fd, rxq_idx;
+	struct netdev_nl_sock *priv;
 	struct net_device *netdev;
 	struct sk_buff *rsp;
 	struct nlattr *attr;
···
 	ifindex = nla_get_u32(info->attrs[NETDEV_A_DEV_IFINDEX]);
 	dmabuf_fd = nla_get_u32(info->attrs[NETDEV_A_DMABUF_FD]);
 
-	sock_binding_list = genl_sk_priv_get(&netdev_nl_family,
-					     NETLINK_CB(skb).sk);
-	if (IS_ERR(sock_binding_list))
-		return PTR_ERR(sock_binding_list);
+	priv = genl_sk_priv_get(&netdev_nl_family, NETLINK_CB(skb).sk);
+	if (IS_ERR(priv))
+		return PTR_ERR(priv);
 
 	rsp = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
 	if (!rsp)
···
 			goto err_unbind;
 	}
 
-	list_add(&binding->list, sock_binding_list);
+	list_add(&binding->list, &priv->bindings);
 
 	nla_put_u32(rsp, NETDEV_A_DMABUF_ID, binding->id);
 	genlmsg_end(rsp, hdr);
···
 	return err;
 }
 
-void netdev_nl_sock_priv_init(struct list_head *priv)
+void netdev_nl_sock_priv_init(struct netdev_nl_sock *priv)
 {
-	INIT_LIST_HEAD(priv);
+	INIT_LIST_HEAD(&priv->bindings);
 }
 
-void netdev_nl_sock_priv_destroy(struct list_head *priv)
+void netdev_nl_sock_priv_destroy(struct netdev_nl_sock *priv)
 {
 	struct net_devmem_dmabuf_binding *binding;
 	struct net_devmem_dmabuf_binding *temp;
 
-	list_for_each_entry_safe(binding, temp, priv, list) {
+	list_for_each_entry_safe(binding, temp, &priv->bindings, list) {
 		rtnl_lock();
 		net_devmem_unbind_dmabuf(binding);
 		rtnl_unlock();