[PATCH net-next v6 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>
---
v5 -> v6: - Locking issue got fixed in a separate patch so rebase
V4 -> V5: - Fail immediately if macsec ops does not exist
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 | 116 +++++++++++++++++++++----------------------
 1 file changed, 57 insertions(+), 59 deletions(-)

diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index bf8ac7a3ded7..1974c59977aa 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -2583,95 +2583,87 @@ 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 = 0;
 
-	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;
-
-	rtnl_lock();
-
-	dev = get_dev_from_nl(genl_info_net(info), attrs);
-	if (IS_ERR(dev)) {
-		ret = PTR_ERR(dev);
-		goto out;
-	}
 	macsec = macsec_priv(dev);
 
-	if (!tb_offload[MACSEC_OFFLOAD_ATTR_TYPE]) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	offload = nla_get_u8(tb_offload[MACSEC_OFFLOAD_ATTR_TYPE]);
 	if (macsec->offload == offload)
-		goto out;
+		return 0;
 
 	/* Check if the offloading mode is supported by the underlying layers */
 	if (offload != MACSEC_OFFLOAD_OFF &&
 	    !macsec_check_offload(offload, macsec)) {
-		ret = -EOPNOTSUPP;
-		goto out;
+		return -EOPNOTSUPP;
 	}
 
 	/* Check if the net device is busy. */
-	if (netif_running(dev)) {
-		ret = -EBUSY;
-		goto out;
-	}
-
-	prev_offload = macsec->offload;
-	macsec->offload = offload;
+	if (netif_running(dev))
+		return -EBUSY;
 
 	/* 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) {
-		ret = -EOPNOTSUPP;
-		goto rollback;
-	}
+	if (!ops)
+		return -EOPNOTSUPP;
 
-	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);
+
+	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);
 
-rollback:
-	macsec->offload = prev_offload;
-out:
 	rtnl_unlock();
+
 	return ret;
 }
 
@@ -3840,6 +3832,12 @@ 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