[PATCH net-next v4 1/2] macsec: add support for IFLA_MACSEC_OFFLOAD in macsec_changelink

[<ehakim@nvidia.com>]

From: Emeel Hakim <ehakim@nvidia.com>

Add support for changing Macsec offload selection through the
netlink layer by implementing the relevant changes in
macsec_changelink.

Since the handling in macsec_changelink is similar to macsec_upd_offload,
update macsec_upd_offload to use a common helper function to avoid
duplication.

Example for setting offload for a macsec device:
    ip link set macsec0 type macsec offload mac

Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Emeel Hakim <ehakim@nvidia.com>
---
V3 -> V4: - Dont pass whole attributes data to macsec_update_offload, just pass relevant attribute.
		  - Fix code style.
		  - Remove macsec_changelink_upd_offload
V2 -> V3: - Split the original patch into 3 patches, the macsec_rtnl_policy related change (separate patch)
                       to be sent to "net" branch as a fix.
                 - Change the original patch title to make it clear that it's only adding IFLA_MACSEC_OFFLOAD
                   to changelink
V1 -> V2: Add common helper to avoid duplicating code

 drivers/net/macsec.c | 100 +++++++++++++++++++++++--------------------
 1 file changed, 53 insertions(+), 47 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index d73b9d535b7a..abfe4a612a2d 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -2583,38 +2583,16 @@ static bool macsec_is_configured(struct macsec_dev *macsec)
 	return false;
 }
 
-static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
+static int macsec_update_offload(struct net_device *dev, enum macsec_offload offload)
 {
-	struct nlattr *tb_offload[MACSEC_OFFLOAD_ATTR_MAX + 1];
-	enum macsec_offload offload, prev_offload;
-	int (*func)(struct macsec_context *ctx);
-	struct nlattr **attrs = info->attrs;
-	struct net_device *dev;
+	enum macsec_offload prev_offload;
 	const struct macsec_ops *ops;
 	struct macsec_context ctx;
 	struct macsec_dev *macsec;
-	int ret;
-
-	if (!attrs[MACSEC_ATTR_IFINDEX])
-		return -EINVAL;
-
-	if (!attrs[MACSEC_ATTR_OFFLOAD])
-		return -EINVAL;
-
-	if (nla_parse_nested_deprecated(tb_offload, MACSEC_OFFLOAD_ATTR_MAX,
-					attrs[MACSEC_ATTR_OFFLOAD],
-					macsec_genl_offload_policy, NULL))
-		return -EINVAL;
+	int ret = 0;
 
-	dev = get_dev_from_nl(genl_info_net(info), attrs);
-	if (IS_ERR(dev))
-		return PTR_ERR(dev);
 	macsec = macsec_priv(dev);
 
-	if (!tb_offload[MACSEC_OFFLOAD_ATTR_TYPE])
-		return -EINVAL;
-
-	offload = nla_get_u8(tb_offload[MACSEC_OFFLOAD_ATTR_TYPE]);
 	if (macsec->offload == offload)
 		return 0;
 
@@ -2627,43 +2605,65 @@ static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
 	if (netif_running(dev))
 		return -EBUSY;
 
-	rtnl_lock();
-
-	prev_offload = macsec->offload;
-	macsec->offload = offload;
-
 	/* Check if the device already has rules configured: we do not support
 	 * rules migration.
 	 */
-	if (macsec_is_configured(macsec)) {
-		ret = -EBUSY;
-		goto rollback;
-	}
+	if (macsec_is_configured(macsec))
+		return -EBUSY;
+
+	prev_offload = macsec->offload;
 
 	ops = __macsec_get_ops(offload == MACSEC_OFFLOAD_OFF ? prev_offload : offload,
 			       macsec, &ctx);
-	if (!ops) {
+	if (!ops)
 		ret = -EOPNOTSUPP;
-		goto rollback;
-	}
 
-	if (prev_offload == MACSEC_OFFLOAD_OFF)
-		func = ops->mdo_add_secy;
-	else
-		func = ops->mdo_del_secy;
+	macsec->offload = offload;
 
 	ctx.secy = &macsec->secy;
-	ret = macsec_offload(func, &ctx);
+	ret = offload == MACSEC_OFFLOAD_OFF ? macsec_offload(ops->mdo_del_secy, &ctx)
+					    : macsec_offload(ops->mdo_add_secy, &ctx);
+
 	if (ret)
-		goto rollback;
+		macsec->offload = prev_offload;
 
-	rtnl_unlock();
-	return 0;
+	return ret;
+}
+
+static int macsec_upd_offload(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr *tb_offload[MACSEC_OFFLOAD_ATTR_MAX + 1];
+	struct nlattr **attrs = info->attrs;
+	enum macsec_offload offload;
+	struct net_device *dev;
+	int ret;
+
+	if (!attrs[MACSEC_ATTR_IFINDEX])
+		return -EINVAL;
+
+	if (!attrs[MACSEC_ATTR_OFFLOAD])
+		return -EINVAL;
+
+	if (nla_parse_nested_deprecated(tb_offload, MACSEC_OFFLOAD_ATTR_MAX,
+					attrs[MACSEC_ATTR_OFFLOAD],
+					macsec_genl_offload_policy, NULL))
+		return -EINVAL;
+
+	dev = get_dev_from_nl(genl_info_net(info), attrs);
+	if (IS_ERR(dev))
+		return PTR_ERR(dev);
 
-rollback:
-	macsec->offload = prev_offload;
+	if (!tb_offload[MACSEC_OFFLOAD_ATTR_TYPE])
+		return -EINVAL;
+
+	offload = nla_get_u8(tb_offload[MACSEC_OFFLOAD_ATTR_TYPE]);
+
+	rtnl_lock();
+
+	ret = macsec_update_offload(dev, offload);
 
 	rtnl_unlock();
+
 	return ret;
 }
 
@@ -3831,6 +3831,12 @@ static int macsec_changelink(struct net_device *dev, struct nlattr *tb[],
 	if (ret)
 		goto cleanup;
 
+	if (data[IFLA_MACSEC_OFFLOAD]) {
+		ret = macsec_update_offload(dev, nla_get_u8(data[IFLA_MACSEC_OFFLOAD]));
+		if (ret)
+			goto cleanup;
+	}
+
 	/* If h/w offloading is available, propagate to the device */
 	if (macsec_is_offloaded(macsec)) {
 		const struct macsec_ops *ops;
-- 
2.21.3