Add script for builtin module building.

This commit introduces a "copy-builtin" script designed to prepare a
kernel source tree for building ZFS as a builtin module. The script
makes a full copy of all needed files, thus making the kernel source
tree fully independent of the zfs source package.

To achieve that, some compilation flags (-include, -I) have been moved
to module/Makefile. This Makefile is only used when compiling external
modules; when compiling builtin modules, a Kbuild file generated by the
configure-builtin script is used instead. This makes sure Makefiles
inside the kernel source tree does not contain references to the zfs
source package.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #851

README.markdown

@@ -7,5 +7,11 @@ and ZVOL with a ZFS Posix Layer (ZPL) on the way!
     $ ./configure
     $ make pkg
 
+To copy the kernel code inside your kernel source tree for builtin
+compilation:
+
+    $ ./configure --enable-linux-builtin --with-linux=/usr/src/linux-...
+    $ ./copy-builtin /usr/src/linux-...
+
 Full documentation for building, configuring, and using ZFS can be
 found at: <http://zfsonlinux.org>

copy-builtin

@@ -0,0 +1,121 @@
+#!/bin/bash
+
+set -e
+
+usage()
+{
+	echo "usage: $0 <kernel source tree>" >&2
+	exit 1
+}
+
+[ "$#" -eq 1 ] || usage
+KERNEL_DIR="$(readlink --canonicalize-existing "$1")"
+
+MODULES=()
+for MODULE_DIR in module/*
+do
+	[ -d "$MODULE_DIR" ] || continue
+	MODULES+=("${MODULE_DIR##*/}")
+done
+
+if ! [ -e 'zfs_config.h' ]
+then
+	echo >&2
+	echo "    $0: you did not run configure, or you're not in the ZFS source directory." >&2
+	echo "    $0: run configure with --with-linux=$KERNEL_DIR and --enable-linux-builtin." >&2
+	echo >&2
+	exit 1
+fi
+
+make clean || true
+
+rm -rf "$KERNEL_DIR/include/zfs" "$KERNEL_DIR/fs/zfs"
+cp --recursive include "$KERNEL_DIR/include/zfs"
+cp --recursive module "$KERNEL_DIR/fs/zfs"
+cp zfs_config.h "$KERNEL_DIR/"
+
+adjust_obj_paths()
+{
+	local FILE="$1"
+	local LINE OBJPATH
+
+	while IFS='' read -r LINE
+	do
+		OBJPATH="${LINE#\$(MODULE)-objs += }"
+		if [ "$OBJPATH" = "$LINE" ]
+		then
+			echo "$LINE"
+		else
+			echo "\$(MODULE)-objs += ${OBJPATH##*/}"
+		fi
+	done < "$FILE" > "$FILE.new"
+	mv "$FILE.new" "$FILE"
+}
+
+for MODULE in "${MODULES[@]}"
+do
+	adjust_obj_paths "$KERNEL_DIR/fs/zfs/$MODULE/Makefile"
+done
+
+cat > "$KERNEL_DIR/fs/zfs/Kconfig" <<"EOF"
+config ZFS
+	tristate "ZFS"
+	depends on SPL
+	help
+	  This is the ZFS filesystem from the ZFS On Linux project.
+
+	  See http://zfsonlinux.org/
+
+	  To compile this file system support as a module, choose M here.
+
+	  If unsure, say N.
+EOF
+
+{
+	cat <<-"EOF"
+	ZFS_MODULE_CFLAGS  = -I$(srctree)/include/zfs -I$(srctree)/include/spl 
+	ZFS_MODULE_CFLAGS += -include $(srctree)/spl_config.h -include $(srctree)/zfs_config.h
+	export ZFS_MODULE_CFLAGS
+
+	obj-$(CONFIG_ZFS) :=
+	EOF
+
+	for MODULE in "${MODULES[@]}"
+	do
+		echo 'obj-$(CONFIG_ZFS) += ' "$MODULE/"
+	done
+} > "$KERNEL_DIR/fs/zfs/Kbuild"
+
+add_after()
+{
+	local FILE="$1"
+	local MARKER="$2"
+	local NEW="$3"
+	local LINE
+
+	while IFS='' read -r LINE
+	do
+		echo "$LINE"
+
+		if [ -n "$MARKER" -a "$LINE" = "$MARKER" ]
+		then
+			echo "$NEW"
+			MARKER=''
+			if IFS='' read -r LINE
+			then
+				[ "$LINE" != "$NEW" ] && echo "$LINE"
+			fi
+		fi
+	done < "$FILE" > "$FILE.new"
+
+	mv "$FILE.new" "$FILE"
+}
+
+add_after "$KERNEL_DIR/fs/Kconfig" 'if BLOCK' 'source "fs/zfs/Kconfig"'
+add_after "$KERNEL_DIR/fs/Makefile" 'endif' 'obj-$(CONFIG_ZFS) += zfs/'
+
+echo >&2
+echo "    $0: done." >&2
+echo "    $0: now you can build the kernel with ZFS support." >&2
+echo "    $0: make sure you enable ZFS support (CONFIG_ZFS) before building." >&2
+echo >&2

module/Makefile.in

@@ -5,6 +5,11 @@ subdir-m += zcommon
 subdir-m += zfs
 subdir-m += zpios
 
+ZFS_MODULE_CFLAGS += -include @SPL_OBJ@/spl_config.h
+ZFS_MODULE_CFLAGS += -include @abs_top_builddir@/zfs_config.h
+ZFS_MODULE_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
+export ZFS_MODULE_CFLAGS
+
 modules:
 	@# Make the exported SPL symbols available to these modules.
 	@# They may be in the root of SPL_OBJ when building against
@@ -21,7 +26,7 @@ modules:
 		"*** - @SPL_OBJ@/module/@SPL_SYMBOLS@\n"; \
 		exit 1; \
 	fi
-	$(MAKE) -C @LINUX_OBJ@ SUBDIRS=`pwd` @KERNELMAKE_PARAMS@ $@
+	$(MAKE) -C @LINUX_OBJ@ SUBDIRS=`pwd` @KERNELMAKE_PARAMS@ CONFIG_ZFS=m $@
 
 clean:
 	@# Only cleanup the kernel build directories when CONFIG_KERNEL

module/avl/Makefile.in

@@ -1,10 +1,7 @@
 MODULE := zavl
 
-EXTRA_CFLAGS  = @KERNELCPPFLAGS@
+EXTRA_CFLAGS = $(ZFS_MODULE_CFLAGS) @KERNELCPPFLAGS@
-EXTRA_CFLAGS += -include @SPL_OBJ@/spl_config.h
-EXTRA_CFLAGS += -include @abs_top_builddir@/zfs_config.h
-EXTRA_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
 
-obj-m := $(MODULE).o
+obj-$(CONFIG_ZFS) := $(MODULE).o
 
 $(MODULE)-objs += @top_srcdir@/module/avl/avl.o

module/nvpair/Makefile.in

@@ -1,11 +1,8 @@
 MODULE := znvpair
 
-EXTRA_CFLAGS  = @KERNELCPPFLAGS@
+EXTRA_CFLAGS = $(ZFS_MODULE_CFLAGS) @KERNELCPPFLAGS@
-EXTRA_CFLAGS += -include @SPL_OBJ@/spl_config.h
-EXTRA_CFLAGS += -include @abs_top_builddir@/zfs_config.h
-EXTRA_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
 
-obj-m := $(MODULE).o
+obj-$(CONFIG_ZFS) := $(MODULE).o
 
 $(MODULE)-objs += @top_srcdir@/module/nvpair/nvpair.o
 $(MODULE)-objs += @top_srcdir@/module/nvpair/nvpair_alloc_spl.o

module/unicode/Makefile.in

@@ -1,11 +1,8 @@
 MODULE := zunicode
 
-EXTRA_CFLAGS  = @KERNELCPPFLAGS@
+EXTRA_CFLAGS = $(ZFS_MODULE_CFLAGS) @KERNELCPPFLAGS@
-EXTRA_CFLAGS += -include @SPL_OBJ@/spl_config.h
-EXTRA_CFLAGS += -include @abs_top_builddir@/zfs_config.h
-EXTRA_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
 
-obj-m := $(MODULE).o
+obj-$(CONFIG_ZFS) := $(MODULE).o
 
 $(MODULE)-objs += @top_srcdir@/module/unicode/u8_textprep.o
 $(MODULE)-objs += @top_srcdir@/module/unicode/uconv.o

module/zcommon/Makefile.in

@@ -1,11 +1,8 @@
 MODULE := zcommon
 
-EXTRA_CFLAGS  = @KERNELCPPFLAGS@
+EXTRA_CFLAGS = $(ZFS_MODULE_CFLAGS) @KERNELCPPFLAGS@
-EXTRA_CFLAGS += -include @SPL_OBJ@/spl_config.h
-EXTRA_CFLAGS += -include @abs_top_builddir@/zfs_config.h
-EXTRA_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
 
-obj-m := $(MODULE).o
+obj-$(CONFIG_ZFS) := $(MODULE).o
 
 $(MODULE)-objs += @top_srcdir@/module/zcommon/zfs_deleg.o
 $(MODULE)-objs += @top_srcdir@/module/zcommon/zfs_prop.o

module/zfs/Makefile.in

@@ -1,11 +1,8 @@
 MODULE := zfs
 
-EXTRA_CFLAGS += @KERNELCPPFLAGS@
+EXTRA_CFLAGS = $(ZFS_MODULE_CFLAGS) @KERNELCPPFLAGS@
-EXTRA_CFLAGS += -include @SPL_OBJ@/spl_config.h
-EXTRA_CFLAGS += -include @abs_top_builddir@/zfs_config.h
-EXTRA_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
 
-obj-m := $(MODULE).o
+obj-$(CONFIG_ZFS) := $(MODULE).o
 
 $(MODULE)-objs += @top_srcdir@/module/zfs/arc.o
 $(MODULE)-objs += @top_srcdir@/module/zfs/bplist.o

module/zpios/Makefile.in

@@ -1,10 +1,7 @@
 MODULE := zpios
 
-EXTRA_CFLAGS  = @KERNELCPPFLAGS@
+EXTRA_CFLAGS = $(ZFS_MODULE_CFLAGS) @KERNELCPPFLAGS@
-EXTRA_CFLAGS += -include @SPL_OBJ@/spl_config.h
-EXTRA_CFLAGS += -include @abs_top_builddir@/zfs_config.h
-EXTRA_CFLAGS += -I@abs_top_srcdir@/include -I@SPL@/include -I@SPL@
 
-obj-m := $(MODULE).o
+obj-$(CONFIG_ZFS) := $(MODULE).o
 
 $(MODULE)-objs += @top_srcdir@/module/zpios/pios.o