Compile kernel modules separately

Preface

When developing and debugging a kernel module , If the kernel is compiled as a whole , That's too inefficient . We usually compile separately .

step 1

Copy kernel module to workspace, Driven by Intel Ethernet card drivers/net/ethernet/intel/ For example

cp linux-5.13/drivers/net/ethernet/intel/ ./ -rf

step 2

rewrite Makefile
original

# SPDX-License-Identifier: GPL-2.0
#
# Makefile for the Intel network device drivers.
#

obj-$(CONFIG_E100) += e100.o
obj-$(CONFIG_E1000) += e1000/
obj-$(CONFIG_E1000E) += e1000e/
obj-$(CONFIG_IGB) += igb/
obj-$(CONFIG_IGC) += igc/
obj-$(CONFIG_IGBVF) += igbvf/
obj-$(CONFIG_IXGBE) += ixgbe/
obj-$(CONFIG_IXGBEVF) += ixgbevf/
obj-$(CONFIG_I40E) += i40e/
obj-$(CONFIG_IXGB) += ixgb/
obj-$(CONFIG_IAVF) += iavf/
obj-$(CONFIG_FM10K) += fm10k/
obj-$(CONFIG_ICE) += ice/

After rewriting

# SPDX-License-Identifier: GPL-2.0
#
# Makefile for the Intel network device drivers.
#

obj-m += e100.o
obj-m += e1000/
#obj-$(CONFIG_E1000E) += e1000e/
#obj-$(CONFIG_IGB) += igb/
#obj-$(CONFIG_IGC) += igc/
#obj-$(CONFIG_IGBVF) += igbvf/
#obj-$(CONFIG_IXGBE) += ixgbe/
#obj-$(CONFIG_IXGBEVF) += ixgbevf/
#obj-$(CONFIG_I40E) += i40e/
#obj-$(CONFIG_IXGB) += ixgb/
#obj-$(CONFIG_IAVF) += iavf/
#obj-$(CONFIG_FM10K) += fm10k/
#obj-$(CONFIG_ICE) += ice/

KDIR=/lib/modules/$(shell uname -r)/build
DIRS := . $(shell find -type d)
GARBAGE_PATTERNS := *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions *.mod *.order *.symvers
GARBAGE := $(foreach DIR,$(DIRS),$(addprefix $(DIR)/,$(GARBAGE_PATTERNS)))

all:
	$(MAKE) -C $(KDIR) M=$(shell pwd) modules

clean:
	rm -rf $(GARBAGE)

Comment out unnecessary modules , Add the required modules to obj-m.
OK