[PATCH net-next v2 1/5] net: Add netdev_config helpers

["Björn Töpel" <bjorn@kernel.org>]

From: Jakub Kicinski <kuba@kernel.org>

netdev_config manipulation will become slightly more complicated
soon and will be used by both ethtool and the queue API.
Encapsulate the logic in helper functions.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Björn Töpel <bjorn@kernel.org>
---
 net/core/dev.c           |  7 ++-----
 net/core/dev.h           |  5 +++++
 net/core/netdev_config.c | 37 +++++++++++++++++++++++++++++++++++++
 net/ethtool/netlink.c    | 15 +++++++--------
 4 files changed, 51 insertions(+), 13 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 290e0f099e6b..4a7c5a5e48e5 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -12195,10 +12195,8 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	if (!dev->ethtool)
 		goto free_all;
 
-	dev->cfg = kzalloc_obj(*dev->cfg, GFP_KERNEL_ACCOUNT);
-	if (!dev->cfg)
+	if (netdev_alloc_config(dev))
 		goto free_all;
-	dev->cfg_pending = dev->cfg;
 
 	dev->num_napi_configs = maxqs;
 	napi_config_sz = array_size(maxqs, sizeof(*dev->napi_config));
@@ -12270,8 +12268,7 @@ void free_netdev(struct net_device *dev)
 		return;
 	}
 
-	WARN_ON(dev->cfg != dev->cfg_pending);
-	kfree(dev->cfg);
+	netdev_free_config(dev);
 	kfree(dev->ethtool);
 	netif_free_tx_queues(dev);
 	netif_free_rx_queues(dev);
diff --git a/net/core/dev.h b/net/core/dev.h
index b757faead4d1..4b52ff779cba 100644
--- a/net/core/dev.h
+++ b/net/core/dev.h
@@ -102,6 +102,11 @@ extern struct rw_semaphore dev_addr_sem;
 extern struct list_head net_todo_list;
 void netdev_run_todo(void);
 
+int netdev_alloc_config(struct net_device *dev);
+void __netdev_free_config(struct netdev_config *cfg);
+void netdev_free_config(struct net_device *dev);
+int netdev_reconfig_start(struct net_device *dev);
+
 int netdev_queue_config_validate(struct net_device *dev, int rxq_idx,
 				 struct netdev_queue_config *qcfg,
 				 struct netlink_ext_ack *extack);
diff --git a/net/core/netdev_config.c b/net/core/netdev_config.c
index f14af365d5cd..b101341e3251 100644
--- a/net/core/netdev_config.c
+++ b/net/core/netdev_config.c
@@ -6,6 +6,43 @@
 
 #include "dev.h"
 
+int netdev_alloc_config(struct net_device *dev)
+{
+	struct netdev_config *cfg;
+
+	cfg = kzalloc_obj(*dev->cfg, GFP_KERNEL_ACCOUNT);
+	if (!cfg)
+		return -ENOMEM;
+
+	dev->cfg = cfg;
+	dev->cfg_pending = cfg;
+	return 0;
+}
+
+void __netdev_free_config(struct netdev_config *cfg)
+{
+	kfree(cfg);
+}
+
+void netdev_free_config(struct net_device *dev)
+{
+	WARN_ON(dev->cfg != dev->cfg_pending);
+	__netdev_free_config(dev->cfg);
+}
+
+int netdev_reconfig_start(struct net_device *dev)
+{
+	struct netdev_config *cfg;
+
+	WARN_ON(dev->cfg != dev->cfg_pending);
+	cfg = kmemdup(dev->cfg, sizeof(*dev->cfg), GFP_KERNEL_ACCOUNT);
+	if (!cfg)
+		return -ENOMEM;
+
+	dev->cfg_pending = cfg;
+	return 0;
+}
+
 static int netdev_nop_validate_qcfg(struct net_device *dev,
 				    struct netdev_queue_config *qcfg,
 				    struct netlink_ext_ack *extack)
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index 1af395b54330..383e911f50f7 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -11,6 +11,8 @@
 #include "module_fw.h"
 #include "netlink.h"
 
+#include "../core/dev.h"
+
 static struct genl_family ethtool_genl_family;
 
 static bool ethnl_ok __read_mostly;
@@ -934,12 +936,9 @@ static int ethnl_default_set_doit(struct sk_buff *skb, struct genl_info *info)
 	if (need_rtnl)
 		rtnl_lock();
 	netdev_lock_ops(dev);
-	dev->cfg_pending = kmemdup(dev->cfg, sizeof(*dev->cfg),
-				   GFP_KERNEL_ACCOUNT);
-	if (!dev->cfg_pending) {
-		ret = -ENOMEM;
-		goto out_tie_cfg;
-	}
+	ret = netdev_reconfig_start(dev);
+	if (ret)
+		goto out_unlock;
 
 	ret = ethnl_ops_begin(dev);
 	if (ret < 0)
@@ -958,9 +957,9 @@ static int ethnl_default_set_doit(struct sk_buff *skb, struct genl_info *info)
 out_ops:
 	ethnl_ops_complete(dev);
 out_free_cfg:
-	kfree(dev->cfg_pending);
-out_tie_cfg:
+	__netdev_free_config(dev->cfg_pending);
 	dev->cfg_pending = dev->cfg;
+out_unlock:
 	netdev_unlock_ops(dev);
 	if (need_rtnl)
 		rtnl_unlock();
-- 
2.55.0