IB/core: Add netdev to path record

In order to find the sgid_index, one could just query the IB cache
with the correct GID and netdevice. Therefore, instead of storing
the L2 attributes directly in the path, we only store the
ifindex and net and use them later to get the sgid_index.
The vlan_id and smac L2 attributes are removed in a later patch.
Signed-off-by: Matan Barak <matanb@mellanox.com>
Reviewed-By: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/sa_query.c

@@ -1007,18 +1007,25 @@ int ib_init_ah_from_path(struct ib_device *device, u8 port_num,
 	force_grh = rdma_cap_eth_ah(device, port_num);
 
 	if (rec->hop_limit > 1 || force_grh) {
+		struct net_device *ndev = ib_get_ndev_from_path(rec);
+
 		ah_attr->ah_flags = IB_AH_GRH;
 		ah_attr->grh.dgid = rec->dgid;
 
-		ret = ib_find_cached_gid(device, &rec->sgid, NULL, &port_num,
+		ret = ib_find_cached_gid(device, &rec->sgid, ndev, &port_num,
 					 &gid_index);
-		if (ret)
+		if (ret) {
+			if (ndev)
+				dev_put(ndev);
 			return ret;
+		}
 
 		ah_attr->grh.sgid_index    = gid_index;
 		ah_attr->grh.flow_label    = be32_to_cpu(rec->flow_label);
 		ah_attr->grh.hop_limit     = rec->hop_limit;
 		ah_attr->grh.traffic_class = rec->traffic_class;
+		if (ndev)
+			dev_put(ndev);
 	}
 	if (force_grh) {
 		memcpy(ah_attr->dmac, rec->dmac, ETH_ALEN);
@@ -1151,6 +1158,8 @@ static void ib_sa_path_rec_callback(struct ib_sa_query *sa_query,
 		ib_unpack(path_rec_table, ARRAY_SIZE(path_rec_table),
 			  mad->data, &rec);
 		rec.vlan_id = 0xffff;
+		rec.net = NULL;
+		rec.ifindex = 0;
 		memset(rec.dmac, 0, ETH_ALEN);
 		memset(rec.smac, 0, ETH_ALEN);
 		query->callback(status, &rec, query->context);

drivers/infiniband/core/uverbs_marshall.c

@@ -144,5 +144,7 @@ void ib_copy_path_rec_from_user(struct ib_sa_path_rec *dst,
 	memset(dst->smac, 0, sizeof(dst->smac));
 	memset(dst->dmac, 0, sizeof(dst->dmac));
 	dst->vlan_id = 0xffff;
+	dst->net = NULL;
+	dst->ifindex = 0;
 }
 EXPORT_SYMBOL(ib_copy_path_rec_from_user);

include/rdma/ib_sa.h

@@ -39,6 +39,7 @@
 #include <linux/compiler.h>
 
 #include <linux/atomic.h>
+#include <linux/netdevice.h>
 
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_mad.h>
@@ -157,8 +158,17 @@ struct ib_sa_path_rec {
 	u8           smac[ETH_ALEN];
 	u8           dmac[ETH_ALEN];
 	u16	     vlan_id;
+	/* ignored in IB */
+	int	     ifindex;
+	/* ignored in IB */
+	struct net  *net;
 };
 
+static inline struct net_device *ib_get_ndev_from_path(struct ib_sa_path_rec *rec)
+{
+	return rec->net ? dev_get_by_index(rec->net, rec->ifindex) : NULL;
+}
+
 #define IB_SA_MCMEMBER_REC_MGID				IB_SA_COMP_MASK( 0)
 #define IB_SA_MCMEMBER_REC_PORT_GID			IB_SA_COMP_MASK( 1)
 #define IB_SA_MCMEMBER_REC_QKEY				IB_SA_COMP_MASK( 2)