Provide implementations of dma_map_page_attrs and dma_unmap_page_attrs from
7.5's include/linux/dma-mapping.h.
Index: src/drivers/net/ethernet/intel/i40evf/i40e_backport_compat.h
===================================================================
--- src.orig/drivers/net/ethernet/intel/i40evf/i40e_backport_compat.h	2018-02-27 18:27:39.893459214 +0100
+++ src/drivers/net/ethernet/intel/i40evf/i40e_backport_compat.h	2018-02-27 18:28:29.908933816 +0100
@@ -1,3 +1,34 @@
 #ifndef I40EVF_BACKPORT_COMPAT_H
 #define I40EVF_BACKPORT_COMPAT_H
+
+static inline dma_addr_t dma_map_page_attrs(struct device *dev,
+					    struct page *page,
+					    size_t offset, size_t size,
+					    enum dma_data_direction dir,
+					    struct dma_attrs *attrs)
+{
+	struct dma_map_ops *ops = get_dma_ops(dev);
+	dma_addr_t addr;
+
+	kmemcheck_mark_initialized(page_address(page) + offset, size);
+	BUG_ON(!valid_dma_direction(dir));
+	addr = ops->map_page(dev, page, offset, size, dir, attrs);
+	debug_dma_map_page(dev, page, offset, size, dir, addr, false);
+
+	return addr;
+}
+
+static inline void dma_unmap_page_attrs(struct device *dev,
+					dma_addr_t addr, size_t size,
+					enum dma_data_direction dir,
+					struct dma_attrs *attrs)
+{
+	struct dma_map_ops *ops = get_dma_ops(dev);
+
+	BUG_ON(!valid_dma_direction(dir));
+	if (ops->unmap_page)
+		ops->unmap_page(dev, addr, size, dir, attrs);
+	debug_dma_unmap_page(dev, addr, size, dir, false);
+}
+
 #endif /* I40EVF_BACKPORT_COMPAT_H */
Index: src/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
===================================================================
--- src.orig/drivers/net/ethernet/intel/i40evf/i40e_txrx.c	2018-02-27 16:16:09.552096211 +0100
+++ src/drivers/net/ethernet/intel/i40evf/i40e_txrx.c	2018-02-27 18:28:58.244636160 +0100
@@ -31,6 +31,8 @@
 #include "i40e_trace.h"
 #include "i40e_prototype.h"
 
+#include "i40e_backport_compat.h"
+
 static inline __le64 build_ctob(u32 td_cmd, u32 td_offset, unsigned int size,
 				u32 td_tag)
 {