RDMA: Introduce and use GID attr helper to read RoCE L2 fields

Instead of RoCE drivers figuring out vlan, smac fields while working on
QP/AH, provide a helper routine to read the L2 fields such as vlan_id and
source mac address.

This moves logic from mlx5 driver to core for wider usage for RoCE ports.

This is a preparation patch to allow detaching netdev in subsequent patch.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/drivers/infiniband/core/cache.c b/drivers/infiniband/core/cache.c
index 7499e7016e38..c164e377e563 100644
--- a/drivers/infiniband/core/cache.c
+++ b/drivers/infiniband/core/cache.c
@@ -1250,6 +1250,61 @@ struct net_device *rdma_read_gid_attr_ndev_rcu(const struct ib_gid_attr *attr)
 	return ndev;
 }
 
+static int get_lower_dev_vlan(struct net_device *lower_dev, void *data)
+{
+	u16 *vlan_id = data;
+
+	if (is_vlan_dev(lower_dev))
+		*vlan_id = vlan_dev_vlan_id(lower_dev);
+
+	/* We are interested only in first level vlan device, so
+	 * always return 1 to stop iterating over next level devices.
+	 */
+	return 1;
+}
+
+/**
+ * rdma_read_gid_l2_fields - Read the vlan ID and source MAC address
+ *			     of a GID entry.
+ *
+ * @attr:	GID attribute pointer whose L2 fields to be read
+ * @vlan_id:	Pointer to vlan id to fill up if the GID entry has
+ *		vlan id. It is optional.
+ * @smac:	Pointer to smac to fill up for a GID entry. It is optional.
+ *
+ * rdma_read_gid_l2_fields() returns 0 on success and returns vlan id
+ * (if gid entry has vlan) and source MAC, or returns error.
+ */
+int rdma_read_gid_l2_fields(const struct ib_gid_attr *attr,
+			    u16 *vlan_id, u8 *smac)
+{
+	struct net_device *ndev;
+
+	ndev = attr->ndev;
+	if (!ndev)
+		return -EINVAL;
+
+	if (smac)
+		ether_addr_copy(smac, ndev->dev_addr);
+	if (vlan_id) {
+		*vlan_id = 0xffff;
+		if (is_vlan_dev(ndev)) {
+			*vlan_id = vlan_dev_vlan_id(ndev);
+		} else {
+			/* If the netdev is upper device and if it's lower
+			 * device is vlan device, consider vlan id of the
+			 * the lower vlan device for this gid entry.
+			 */
+			rcu_read_lock();
+			netdev_walk_all_lower_dev_rcu(attr->ndev,
+					get_lower_dev_vlan, vlan_id);
+			rcu_read_unlock();
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(rdma_read_gid_l2_fields);
+
 static int config_non_roce_gid_cache(struct ib_device *device,
 				     u8 port, int gid_tbl_len)
 {