使用OFA变量指定Makefile引用模块

KVER ?= $(shell uname -r)
SRC_DIR ?= $(shell pwd)
OFA_DIR ?= /usr/src/ofa_kernel

knownvariants=(default|trace|ppc64|bigsmp|debug|ppc|kdump|kdumppae|smp|vmi|vmipae|xen|xenpae|pae)
verrel=$(shell echo $(KVER) | sed -r -e s'/-$(knownvariants)//g')
ifneq ($(verrel),$(KVER))
variant1=$(shell echo $(KVER) | sed -r -e s'/$(verrel)[-]//g')
variant=$(shell test -d $(OFA_DIR)/$(variant1) && echo $(variant1) || echo default)
else
variant=default
endif
FLAVOR ?= $(variant)
OFA = $(shell ( test -d $(OFA_DIR)/$(KVER) && echo $(OFA_DIR)/$(KVER) ) || ( test -d $(OFA_DIR)/$(FLAVOR) && echo $(OFA_DIR)/$(FLAVOR) ) || ( test -d /var/lib/dkms/mlnx-ofed-kernel/ && ls -d /var/lib/dkms/mlnx-ofed-kernel/*/build ) || ( echo $(OFA_DIR) ))

ifneq ($(shell test -d $(OFA) && echo "true" || echo "" ),)
include $(OFA)/configure.mk.kernel
endif

export KERNELRELEASE=$(KVER)
K_BUILD ?= /lib/modules/$(KVER)/build
K_OBJ ?= $(K_BUILD)
K_SRC ?= $(shell test -d /lib/modules/$(KVER)/source && echo /lib/modules/$(KVER)/source || echo $(K_BUILD))

EXTRA_CFLAGS += $(shell echo $(BACKPORT_INCLUDES) | sed -e 's@/var/tmp/OFED_topdir/BUILD@/usr/src@')

autoconf_h=$(shell /bin/ls -1 $(K_BUILD)/include/*/autoconf.h 2> /dev/null | head -1)
kconfig_h=$(shell /bin/ls -1 $(K_BUILD)/include/*/kconfig.h 2> /dev/null | head -1)

ifneq ($(kconfig_h),)