IB/core: Reduce the places that use zgid

Instead of open coding memcmp() to check whether a given GID is zero or
not, use a helper function to do so, and replace instances of
memcpy(z,&zgid) with memset.
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/cache.c

@@ -125,6 +125,16 @@ const char *ib_cache_gid_type_str(enum ib_gid_type gid_type)
 }
 EXPORT_SYMBOL(ib_cache_gid_type_str);
 
+/** rdma_is_zero_gid - Check if given GID is zero or not.
+ * @gid:	GID to check
+ * Returns true if given GID is zero, returns false otherwise.
+ */
+bool rdma_is_zero_gid(const union ib_gid *gid)
+{
+	return !memcmp(gid, &zgid, sizeof(*gid));
+}
+EXPORT_SYMBOL(rdma_is_zero_gid);
+
 int ib_cache_gid_parse_type_str(const char *buf)
 {
 	unsigned int i;
@@ -231,7 +241,7 @@ static int add_modify_gid(struct ib_gid_table *table,
 		 * So ignore such behavior for IB link layer and don't
 		 * fail the call, but don't add such entry to GID cache.
 		 */
-		if (!memcmp(gid, &zgid, sizeof(*gid)))
+		if (rdma_is_zero_gid(gid))
 			return 0;
 	}
 
@@ -264,7 +274,7 @@ static void del_gid(struct ib_device *ib_dev, u8 port,
 
 	if (rdma_protocol_roce(ib_dev, port))
 		del_roce_gid(ib_dev, port, table, ix);
-	memcpy(&table->data_vec[ix].gid, &zgid, sizeof(zgid));
+	memset(&table->data_vec[ix].gid, 0, sizeof(table->data_vec[ix].gid));
 	memset(&table->data_vec[ix].attr, 0, sizeof(table->data_vec[ix].attr));
 	table->data_vec[ix].context = NULL;
 }
@@ -363,7 +373,7 @@ static int __ib_cache_gid_add(struct ib_device *ib_dev, u8 port,
 	 * IB spec version 1.3 section 4.1.1 point (6) and
 	 * section 12.7.10 and section 12.7.20
 	 */
-	if (!memcmp(gid, &zgid, sizeof(*gid)))
+	if (rdma_is_zero_gid(gid))
 		return -EINVAL;
 
 	table = ib_dev->cache.ports[port - rdma_start_port(ib_dev)].gid;
@@ -724,8 +734,7 @@ static void cleanup_gid_table_port(struct ib_device *ib_dev, u8 port,
 
 	mutex_lock(&table->lock);
 	for (i = 0; i < table->sz; ++i) {
-		if (memcmp(&table->data_vec[i].gid, &zgid,
-			   sizeof(table->data_vec[i].gid))) {
+		if (!rdma_is_zero_gid(&table->data_vec[i].gid)) {
 			del_gid(ib_dev, port, table, i);
 			deleted = true;
 		}

drivers/infiniband/hw/mlx4/main.c

@@ -276,7 +276,7 @@ static int mlx4_ib_add_gid(const union ib_gid *gid,
 			found = i;
 			break;
 		}
-		if (free < 0 && !memcmp(&port_gid_table->gids[i].gid, &zgid, sizeof(*gid)))
+		if (free < 0 && rdma_is_zero_gid(&port_gid_table->gids[i].gid))
 			free = i; /* HW has space */
 	}
 
@@ -345,7 +345,8 @@ static int mlx4_ib_del_gid(const struct ib_gid_attr *attr, void **context)
 		if (!ctx->refcount) {
 			unsigned int real_index = ctx->real_index;
 
-			memcpy(&port_gid_table->gids[real_index].gid, &zgid, sizeof(zgid));
+			memset(&port_gid_table->gids[real_index].gid, 0,
+			       sizeof(port_gid_table->gids[real_index].gid));
 			kfree(port_gid_table->gids[real_index].ctx);
 			port_gid_table->gids[real_index].ctx = NULL;
 			hw_update = 1;

drivers/infiniband/hw/mlx4/qp.c

@@ -3078,7 +3078,7 @@ static int fill_gid_by_hw_index(struct mlx4_ib_dev *ibdev, u8 port_num,
 	memcpy(gid, &port_gid_table->gids[index].gid, sizeof(*gid));
 	*gid_type = port_gid_table->gids[index].gid_type;
 	spin_unlock_irqrestore(&iboe->lock, flags);
-	if (!memcmp(gid, &zgid, sizeof(*gid)))
+	if (rdma_is_zero_gid(gid))
 		return -ENOENT;
 
 	return 0;

include/rdma/ib_cache.h

@@ -149,4 +149,5 @@ int ib_get_cached_port_state(struct ib_device *device,
 			      u8                port_num,
 			      enum ib_port_state *port_active);
 
+bool rdma_is_zero_gid(const union ib_gid *gid);
 #endif /* _IB_CACHE_H */