Cleanup linux module kbuild files

The linux module can be built either as an external module, or compiled
into the kernel, using copy-builtin. The source and build directories
are slightly different between the two cases, and currently, compiling
into the kernel still refers to some files from the configured ZFS
source tree, instead of the copies inside the kernel source tree. There
is also duplication between copy-builtin, which creates a Kbuild file to
build ZFS inside the kernel tree, and the top-level module/Makefile.in.

Fix this by moving the list of modules and the CFLAGS settings into a
new module/Kbuild.in, which will be used by the kernel kbuild
infrastructure, and using KBUILD_EXTMOD to distinguish the two cases
within the Makefiles, in order to choose appropriate include
directories etc.

Module CFLAGS setting is simplified by using subdir-ccflags-y (available
since 2.6.30) to set them in the top-level Kbuild instead of each
individual module. The disabling of -Wunused-but-set-variable is removed
from the lua and zfs modules. The variable that the Makefile uses is
actually not defined, so this has no effect; and the warning has long
been disabled by the kernel Makefile itself.

The target_cpu definition in module/{zfs,zcommon} is removed as it was
replaced by use of CONFIG_SPARC64 in
  commit 70835c5b755e ("Unify target_cpu handling")

os/linux/{spl,zfs} are removed from obj-m, as they are not modules in
themselves, but are included by the Makefile in the spl and zfs module
directories. The vestigial Makefiles in os and os/linux are removed.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Arvind Sankar <[email protected]>
Closes #10379
Closes #10421

14 files changed, 86 insertions, 69 deletions

diff --git a/module/.gitignore b/module/.gitignore
index 5f3d70487..7a4bd3673 100644
--- a/module/.gitignore
+++ b/module/.gitignore
@@ -9,6 +9,7 @@
 .*.d
 *.mod
 
+/Kbuild
 /.cache.mk
 /.tmp_versions
 /Module.markers
diff --git a/module/Kbuild.in b/module/Kbuild.in
new file mode 100644
index 000000000..b42ce9e6d
--- /dev/null
+++ b/module/Kbuild.in
@@ -0,0 +1,44 @@
+# When integrated in to a monolithic kernel the spl module must appear
+# first.  This ensures its module initialization function is run before
+# any of the other module initialization functions which depend on it.
+ZFS_MODULES += spl/
+ZFS_MODULES += avl/
+ZFS_MODULES += icp/
+ZFS_MODULES += lua/
+ZFS_MODULES += nvpair/
+ZFS_MODULES += unicode/
+ZFS_MODULES += zcommon/
+ZFS_MODULES += zfs/
+
+# The rest is only relevant when run by kbuild
+ifneq ($(KERNELRELEASE),)
+
+obj-$(CONFIG_ZFS) := $(ZFS_MODULES)
+
+ZFS_MODULE_CFLAGS += -std=gnu99 -Wno-declaration-after-statement
+ZFS_MODULE_CFLAGS += @KERNEL_DEBUG_CFLAGS@  @NO_FORMAT_ZERO_LENGTH@
+
+ifneq ($(KBUILD_EXTMOD),)
+zfs_include = @abs_top_srcdir@/include
+ZFS_MODULE_CFLAGS += -include @abs_top_builddir@/zfs_config.h
+else
+zfs_include = $(srctree)/include/zfs
+ZFS_MODULE_CFLAGS += -include $(zfs_include)/zfs_config.h
+endif
+
+ZFS_MODULE_CFLAGS += -I$(zfs_include)/os/linux/kernel
+ZFS_MODULE_CFLAGS += -I$(zfs_include)/os/linux/spl
+ZFS_MODULE_CFLAGS += -I$(zfs_include)/os/linux/zfs
+ZFS_MODULE_CFLAGS += -I$(zfs_include)
+ZFS_MODULE_CPPFLAGS += -D_KERNEL
+ZFS_MODULE_CPPFLAGS += @KERNEL_DEBUG_CPPFLAGS@
+
+ifneq ($(KBUILD_EXTMOD),)
+@CONFIG_QAT_TRUE@ZFS_MODULE_CFLAGS += -I@QAT_SRC@/include
+@CONFIG_QAT_TRUE@KBUILD_EXTRA_SYMBOLS += @QAT_SYMBOLS@
+endif
+
+subdir-asflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
+subdir-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
+
+endif
diff --git a/module/Makefile.in b/module/Makefile.in
index 39acdac20..3485649dc 100644
--- a/module/Makefile.in
+++ b/module/Makefile.in
@@ -1,31 +1,7 @@
-obj-m += avl/
-obj-m += icp/
-obj-m += lua/
-obj-m += nvpair/
-obj-m += spl/
-obj-m += os/linux/spl/
-obj-m += unicode/
-obj-m += zcommon/
-obj-m += zfs/
-obj-m += os/linux/zfs/
+include Kbuild
 
 INSTALL_MOD_DIR ?= extra
 
-ZFS_MODULE_CFLAGS += -std=gnu99 -Wno-declaration-after-statement
-ZFS_MODULE_CFLAGS += @KERNEL_DEBUG_CFLAGS@  @NO_FORMAT_ZERO_LENGTH@
-ZFS_MODULE_CFLAGS += -include @abs_top_builddir@/zfs_config.h
-ZFS_MODULE_CFLAGS += -I@abs_top_srcdir@/include/os/linux/kernel
-ZFS_MODULE_CFLAGS += -I@abs_top_srcdir@/include/os/linux/spl
-ZFS_MODULE_CFLAGS += -I@abs_top_srcdir@/include/os/linux/zfs
-ZFS_MODULE_CFLAGS += -I@abs_top_srcdir@/include
-ZFS_MODULE_CPPFLAGS += -D_KERNEL
-ZFS_MODULE_CPPFLAGS += @KERNEL_DEBUG_CPPFLAGS@
-
-@CONFIG_QAT_TRUE@ZFS_MODULE_CFLAGS += -I@QAT_SRC@/include
-@CONFIG_QAT_TRUE@KBUILD_EXTRA_SYMBOLS += @QAT_SYMBOLS@
-
-export ZFS_MODULE_CFLAGS ZFS_MODULE_CPPFLAGS
-
 SUBDIR_TARGETS = icp lua
 
 all: modules
@@ -119,7 +95,7 @@ modules_install: modules_install-@ac_system@
 modules_uninstall-Linux:
 	@# Uninstall the kernel modules
 	kmoddir=$(DESTDIR)$(INSTALL_MOD_PATH)/lib/modules/@LINUX_VERSION@
-	list='$(obj-m)'; for objdir in $$list; do \
+	list='$(ZFS_MODULES)'; for objdir in $$list; do \
 		$(RM) -R $$kmoddir/$(INSTALL_MOD_DIR)/$$objdir; \
 	done
 
@@ -129,7 +105,7 @@ modules_uninstall-FreeBSD:
 modules_uninstall: modules_uninstall-@ac_system@
 
 distdir:
-	list='$(obj-m)'; for objdir in $$list; do \
+	list='$(ZFS_MODULES)'; for objdir in $$list os/linux/spl os/linux/zfs; do \
 		(cd @top_srcdir@/module && find $$objdir -name '*.[chS]' | \
 		while read path; do \
 			mkdir -p @abs_top_builddir@/module/$$distdir/$${path%/*}; \
diff --git a/module/avl/Makefile.in b/module/avl/Makefile.in
index 217fa3ca5..991d5f95b 100644
--- a/module/avl/Makefile.in
+++ b/module/avl/Makefile.in
@@ -1,10 +1,10 @@
-src = @abs_top_srcdir@/module/avl
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
+endif
 
 MODULE := zavl
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-
 $(MODULE)-objs += avl.o
diff --git a/module/icp/Makefile.in b/module/icp/Makefile.in
index b6d34d15a..7a01b2f08 100644
--- a/module/icp/Makefile.in
+++ b/module/icp/Makefile.in
@@ -1,14 +1,17 @@
-src = @abs_top_srcdir@/module/icp
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
+icp_include = $(src)/include
+else
+icp_include = $(srctree)/$(src)/include
+endif
 
 MODULE := icp
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-asflags-y := -I@abs_top_srcdir@/module/icp/include
-asflags-y += $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-ccflags-y := -I@abs_top_srcdir@/module/icp/include
-ccflags-y += $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
+asflags-y := -I$(icp_include)
+ccflags-y := -I$(icp_include)
 
 $(MODULE)-objs += illumos-crypto.o
 $(MODULE)-objs += api/kcf_cipher.o
diff --git a/module/lua/Makefile.in b/module/lua/Makefile.in
index d49065fbe..0a74c17e6 100644
--- a/module/lua/Makefile.in
+++ b/module/lua/Makefile.in
@@ -1,16 +1,13 @@
-src = @abs_top_srcdir@/module/lua
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
+endif
 
 MODULE := zlua
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-asflags-y += $(ZFS_MODULE_CFLAGS)
-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-ccflags-y += -DLUA_USE_LONGLONG
-
-# Suppress unused but set variable warnings often due to ASSERTs
-ccflags-y += $(NO_UNUSED_BUT_SET_VARIABLE)
+ccflags-y := -DLUA_USE_LONGLONG
 
 $(MODULE)-objs += lapi.o
 $(MODULE)-objs += lauxlib.o
diff --git a/module/nvpair/Makefile.in b/module/nvpair/Makefile.in
index f420ef98b..d81452366 100644
--- a/module/nvpair/Makefile.in
+++ b/module/nvpair/Makefile.in
@@ -1,12 +1,12 @@
-src = @abs_top_srcdir@/module/nvpair
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
+endif
 
 MODULE := znvpair
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-
 $(MODULE)-objs += nvpair.o
 $(MODULE)-objs += fnvpair.o
 $(MODULE)-objs += nvpair_alloc_spl.o
diff --git a/module/os/Makefile.in b/module/os/Makefile.in
deleted file mode 100644
index b9990d1bc..000000000
--- a/module/os/Makefile.in
+++ /dev/null
@@ -1 +0,0 @@
-subdirs-m = linux
diff --git a/module/os/linux/Makefile.in b/module/os/linux/Makefile.in
deleted file mode 100644
index ab01708a3..000000000
--- a/module/os/linux/Makefile.in
+++ /dev/null
@@ -1 +0,0 @@
-subdirs-m = spl zfs
diff --git a/module/os/linux/zfs/Makefile.in b/module/os/linux/zfs/Makefile.in
index cb4edbbc1..9f493ef16 100644
--- a/module/os/linux/zfs/Makefile.in
+++ b/module/os/linux/zfs/Makefile.in
@@ -5,8 +5,6 @@
 # Suppress unused-value warnings in sparc64 architecture headers
 ccflags-$(CONFIG_SPARC64) += -Wno-unused-value
 
-ccflags-y += -I@abs_top_srcdir@/module/os/linux/zfs
-
 $(MODULE)-objs += ../os/linux/zfs/abd_os.o
 $(MODULE)-objs += ../os/linux/zfs/arc_os.o
 $(MODULE)-objs += ../os/linux/zfs/mmp_os.o
diff --git a/module/spl/Makefile.in b/module/spl/Makefile.in
index 8602f4edd..cedbfe92b 100644
--- a/module/spl/Makefile.in
+++ b/module/spl/Makefile.in
@@ -1,11 +1,13 @@
-src = @abs_top_srcdir@/module/spl
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
+mfdir = $(obj)
+else
+mfdir = $(srctree)/$(src)
+endif
 
 MODULE := spl
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-
-
--include @abs_top_builddir@/module/os/linux/spl/Makefile
+include $(mfdir)/../os/linux/spl/Makefile
diff --git a/module/unicode/Makefile.in b/module/unicode/Makefile.in
index 82c90373a..59c07c455 100644
--- a/module/unicode/Makefile.in
+++ b/module/unicode/Makefile.in
@@ -1,11 +1,11 @@
-src = @abs_top_srcdir@/module/unicode
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
+endif
 
 MODULE := zunicode
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-
 $(MODULE)-objs += u8_textprep.o
 $(MODULE)-objs += uconv.o
diff --git a/module/zcommon/Makefile.in b/module/zcommon/Makefile.in
index 01e0692eb..b5cdf4c0c 100644
--- a/module/zcommon/Makefile.in
+++ b/module/zcommon/Makefile.in
@@ -1,13 +1,12 @@
-src = @abs_top_srcdir@/module/zcommon
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
-target_cpu = @target_cpu@
+endif
 
 MODULE := zcommon
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-
 # Suppress unused-value warnings in sparc64 architecture headers
 ccflags-$(CONFIG_SPARC64) += -Wno-unused-value
 
diff --git a/module/zfs/Makefile.in b/module/zfs/Makefile.in
index 3a9663997..7ea976d12 100644
--- a/module/zfs/Makefile.in
+++ b/module/zfs/Makefile.in
@@ -1,16 +1,15 @@
-src = @abs_top_srcdir@/module/zfs
+ifneq ($(KBUILD_EXTMOD),)
+src = @abs_srcdir@
 obj = @abs_builddir@
-target_cpu = @target_cpu@
+mfdir = $(obj)
+else
+mfdir = $(srctree)/$(src)
+endif
 
 MODULE := zfs
 
 obj-$(CONFIG_ZFS) := $(MODULE).o
 
-ccflags-y := $(ZFS_MODULE_CFLAGS) $(ZFS_MODULE_CPPFLAGS)
-
-# Suppress unused but set variable warnings often due to ASSERTs
-ccflags-y += $(NO_UNUSED_BUT_SET_VARIABLE)
-
 # Suppress unused-value warnings in sparc64 architecture headers
 ccflags-$(CONFIG_SPARC64) += -Wno-unused-value
 
@@ -150,4 +149,4 @@ ifeq ($(CONFIG_ALTIVEC),y)
 $(obj)/vdev_raidz_math_powerpc_altivec.o: c_flags += -maltivec
 endif
 
--include @abs_top_builddir@/module/os/linux/zfs/Makefile
+include $(mfdir)/../os/linux/zfs/Makefile