When checking for symbol exports, try compiling.

This patch adds a new autoconf function: ZFS_LINUX_TRY_COMPILE_SYMBOL.
This new function does the following:

 - Call LINUX_TRY_COMPILE with the specified parameters.
 - If unsuccessful, return false.
 - If successful and we're configuring with --enable-linux-builtin,
   return true.
 - Else, call CHECK_SYMBOL_EXPORT with the specified parameters and
   return the result.

All calls to CHECK_SYMBOL_EXPORT are converted to
LINUX_TRY_COMPILE_SYMBOL so that the tests work even when configuring
for builtin on a kernel which doesn't have loadable module support, or
hasn't been built yet.

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

config/kernel-bdi-setup-and-register.m4

@@ -5,11 +5,17 @@ dnl # exported by the kernel.  This is a trivial helper function but
 dnl # using it significantly simplifies the code surrounding setting
 dnl # up and tearing down the bdi structure.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_BDI_SETUP_AND_REGISTER], [
+AC_DEFUN([ZFS_AC_KERNEL_BDI_SETUP_AND_REGISTER],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether bdi_setup_and_register() is available])
-		[bdi_setup_and_register],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[mm/backing-dev.c],
+		#include <linux/backing-dev.h>
-		[AC_DEFINE(HAVE_BDI_SETUP_AND_REGISTER, 1,
+	], [
-		[bdi_setup_and_register() is available])],
+		bdi_setup_and_register(NULL, NULL, 0);
-		[])
+	], [bdi_setup_and_register], [mm/backing-dev.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_BDI_SETUP_AND_REGISTER, 1,
+		          [bdi_setup_and_register() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-blkdev-get-by-path.m4

@@ -3,11 +3,17 @@ dnl # 2.6.38 API change
 dnl # open_bdev_exclusive() changed to blkdev_get_by_path()
 dnl # close_bdev_exclusive() changed to blkdev_put()
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_BLKDEV_GET_BY_PATH], [
+AC_DEFUN([ZFS_AC_KERNEL_BLKDEV_GET_BY_PATH],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether blkdev_get_by_path() is available])
-		[blkdev_get_by_path],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/block_dev.c],
+		#include <linux/fs.h>
-		[AC_DEFINE(HAVE_BLKDEV_GET_BY_PATH, 1,
+	], [
-		[blkdev_get_by_path() is available])],
+		blkdev_get_by_path(NULL, 0, NULL);
-		[])
+	], [blkdev_get_by_path], [fs/block_dev.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_BLKDEV_GET_BY_PATH, 1,
+		          [blkdev_get_by_path() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-check-disk-size-change.m4

@@ -2,11 +2,17 @@ dnl #
 dnl # 2.6.28 API change
 dnl # Added check_disk_size_change() helper function.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_CHECK_DISK_SIZE_CHANGE], [
+AC_DEFUN([ZFS_AC_KERNEL_CHECK_DISK_SIZE_CHANGE],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether check_disk_size_change() is available])
-		[check_disk_size_change],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/block_dev.c],
+		#include <linux/fs.h>
-		[AC_DEFINE(HAVE_CHECK_DISK_SIZE_CHANGE, 1,
+	], [
-		[check_disk_size_change() is available])],
+		check_disk_size_change(NULL, NULL);
-		[])
+	], [check_disk_size_change], [fs/block_dev.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_CHECK_DISK_SIZE_CHANGE, 1,
+		          [check_disk_size_change() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-clear-inode.m4

@@ -19,11 +19,16 @@ dnl # Therefore, to ensure we have the correct API we only allow the
 dnl # clear_inode() compatibility code to be defined iff the evict_inode()
 dnl # functionality is also detected.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_CLEAR_INODE], [
+AC_DEFUN([ZFS_AC_KERNEL_CLEAR_INODE],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether clear_inode() is available])
-		[clear_inode],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/inode.c],
+		#include <linux/fs.h>
-		[AC_DEFINE(HAVE_CLEAR_INODE, 1,
+	], [
-		[clear_inode() is available])],
+		clear_inode(NULL);
-		[])
+	], [clear_inode], [fs/inode.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_CLEAR_INODE, 1, [clear_inode() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-d-make-root.m4

@@ -2,11 +2,16 @@ dnl #
 dnl # 3.4.0 API change
 dnl # Added d_make_root() to replace previous d_alloc_root() function.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_D_MAKE_ROOT], [
+AC_DEFUN([ZFS_AC_KERNEL_D_MAKE_ROOT],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether d_make_root() is available])
-		[d_make_root],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/dcache.c],
+		#include <linux/dcache.h>
-		[AC_DEFINE(HAVE_D_MAKE_ROOT, 1,
+	], [
-		[d_make_root() is available])],
+		d_make_root(NULL);
-		[])
+	], [d_make_root], [fs/dcache.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_D_MAKE_ROOT, 1, [d_make_root() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-d-obtain-alias.m4

@@ -2,11 +2,17 @@ dnl #
 dnl # 2.6.28 API change
 dnl # Added d_obtain_alias() helper function.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_D_OBTAIN_ALIAS], [
+AC_DEFUN([ZFS_AC_KERNEL_D_OBTAIN_ALIAS],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether d_obtain_alias() is available])
-		[d_obtain_alias],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/dcache.c],
+		#include <linux/dcache.h>
-		[AC_DEFINE(HAVE_D_OBTAIN_ALIAS, 1,
+	], [
-		[d_obtain_alias() is available])],
+		d_obtain_alias(NULL);
-		[])
+	], [d_obtain_alias], [fs/dcache.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_D_OBTAIN_ALIAS, 1,
+		          [d_obtain_alias() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-get-gendisk.m4

@@ -1,11 +1,17 @@
 dnl #
 dnl # 2.6.34 API change
-dnl # Verify the get_gendisk() symbol is exported.
+dnl # Verify the get_gendisk() symbol is available.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_GET_GENDISK], [
+AC_DEFUN([ZFS_AC_KERNEL_GET_GENDISK],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether get_gendisk() is available])
-		[get_gendisk],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[block/genhd.c],
+		#include <linux/genhd.h>
-		[AC_DEFINE(HAVE_GET_GENDISK, 1, [get_gendisk() is available])],
+	], [
-		[])
+		get_gendisk(0, NULL);
+	], [get_gendisk], [block/genhd.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_GET_GENDISK, 1, [get_gendisk() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-insert-inode-locked.m4

@@ -2,11 +2,17 @@ dnl #
 dnl # 2.6.28 API change
 dnl # Added insert_inode_locked() helper function.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_INSERT_INODE_LOCKED], [
+AC_DEFUN([ZFS_AC_KERNEL_INSERT_INODE_LOCKED],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether insert_inode_locked() is available])
-		[insert_inode_locked],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/inode.c],
+		#include <linux/fs.h>
-		[AC_DEFINE(HAVE_INSERT_INODE_LOCKED, 1,
+	], [
-		[insert_inode_locked() is available])],
+		insert_inode_locked(NULL);
-		[])
+	], [insert_inode_locked], [fs/inode.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_INSERT_INODE_LOCKED, 1,
+		          [insert_inode_locked() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-mount-nodev.m4

@@ -5,11 +5,16 @@ dnl # in the file_system_type structure.  When using the new
 dnl # interface the caller must now use the mount_nodev() helper.
 dnl # This updated callback and helper no longer pass the vfsmount.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_MOUNT_NODEV], [
+AC_DEFUN([ZFS_AC_KERNEL_MOUNT_NODEV],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether mount_nodev() is available])
-		[mount_nodev],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/super.c],
+		#include <linux/fs.h>
-		[AC_DEFINE(HAVE_MOUNT_NODEV, 1,
+	], [
-		[mount_nodev() is available])],
+		mount_nodev(NULL, 0, NULL, NULL);
-		[])
+	], [mount_nodev], [fs/super.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_MOUNT_NODEV, 1, [mount_nodev() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-open-bdev-exclusive.m4

@@ -2,11 +2,17 @@ dnl #
 dnl # 2.6.28 API change
 dnl # open/close_bdev_excl() renamed to open/close_bdev_exclusive()
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_OPEN_BDEV_EXCLUSIVE], [
+AC_DEFUN([ZFS_AC_KERNEL_OPEN_BDEV_EXCLUSIVE],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether open_bdev_exclusive() is available])
-		[open_bdev_exclusive],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[fs/block_dev.c],
+		#include <linux/fs.h>
-		[AC_DEFINE(HAVE_OPEN_BDEV_EXCLUSIVE, 1,
+	], [
-		[open_bdev_exclusive() is available])],
+		open_bdev_exclusive(NULL, 0, NULL);
-		[])
+	], [open_bdev_exclusive], [fs/block_dev.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_OPEN_BDEV_EXCLUSIVE, 1,
+		          [open_bdev_exclusive() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel-truncate-setsize.m4

@@ -2,11 +2,17 @@ dnl #
 dnl # 2.6.35 API change
 dnl # Added truncate_setsize() helper function.
 dnl #
-AC_DEFUN([ZFS_AC_KERNEL_TRUNCATE_SETSIZE], [
+AC_DEFUN([ZFS_AC_KERNEL_TRUNCATE_SETSIZE],
-	ZFS_CHECK_SYMBOL_EXPORT(
+	[AC_MSG_CHECKING([whether truncate_setsize() is available])
-		[truncate_setsize],
+	ZFS_LINUX_TRY_COMPILE_SYMBOL([
-		[mm/truncate.c],
+		#include <linux/mm.h>
-		[AC_DEFINE(HAVE_TRUNCATE_SETSIZE, 1,
+	], [
-		[truncate_setsize() is available])],
+		truncate_setsize(NULL, 0);
-		[])
+	], [truncate_setsize], [mm/truncate.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_TRUNCATE_SETSIZE, 1,
+		          [truncate_setsize() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])

config/kernel.m4

@@ -159,7 +159,7 @@ AC_DEFUN([ZFS_AC_KERNEL], [
 		], [test -d ${kernelsrc}-obj/${target_cpu}/${target_cpu}], [
 			kernelbuild=${kernelsrc}-obj/${target_cpu}/${target_cpu}
 		], [test -d ${kernelsrc}-obj/${target_cpu}/default], [
-		        kernelbuild=${kernelsrc}-obj/${target_cpu}/default
+			kernelbuild=${kernelsrc}-obj/${target_cpu}/default
 		], [test -d `dirname ${kernelsrc}`/build-${target_cpu}], [
 			kernelbuild=`dirname ${kernelsrc}`/build-${target_cpu}
 		], [
@@ -491,30 +491,48 @@ dnl #
 dnl # ZFS_CHECK_SYMBOL_EXPORT
 dnl # check symbol exported or not
 dnl #
-AC_DEFUN([ZFS_CHECK_SYMBOL_EXPORT],
+AC_DEFUN([ZFS_CHECK_SYMBOL_EXPORT], [
-	[AC_MSG_CHECKING([whether symbol $1 is exported])
 	grep -q -E '[[[:space:]]]$1[[[:space:]]]' \
 		$LINUX_OBJ/$LINUX_SYMBOLS 2>/dev/null
 	rc=$?
-	AS_IF([test $rc -ne 0], [
+	if test $rc -ne 0; then
 		export=0
 		for file in $2; do
-			grep -q -E "EXPORT_SYMBOL.*($1)" "$LINUX/$file" 2>/dev/null
+			grep -q -E "EXPORT_SYMBOL.*($1)" \
+				"$LINUX/$file" 2>/dev/null
 			rc=$?
-			AS_IF([test $rc -eq 0], [
+			if test $rc -eq 0; then
 				export=1
 				break;
-			])
+			fi
 		done
-		AS_IF([test $export -eq 0], [
+		if test $export -eq 0; then :
-			AC_MSG_RESULT([no])
 			$4
-		], [
+		else :
-			AC_MSG_RESULT([yes])
 			$3
-		])
+		fi
-	], [
+	else :
-		AC_MSG_RESULT([yes])
 		$3
-	])
+	fi
+])
+
+dnl #
+dnl # ZFS_LINUX_TRY_COMPILE_SYMBOL
+dnl # like ZFS_LINUX_TRY_COMPILE, except ZFS_CHECK_SYMBOL_EXPORT
+dnl # is called if not compiling for builtin
+dnl #
+AC_DEFUN([ZFS_LINUX_TRY_COMPILE_SYMBOL], [
+	ZFS_LINUX_TRY_COMPILE([$1], [$2], [rc=0], [rc=1])
+	if test $rc -ne 0; then :
+		$6
+	else
+		if test "x$enable_linux_builtin" != xyes; then
+			ZFS_CHECK_SYMBOL_EXPORT([$3], [$4], [rc=0], [rc=1])
+		fi
+		if test $rc -ne 0; then :
+			$6
+		else :
+			$5
+		fi
+	fi
 ])