From fd7578215e504919b6db6d4043f68a91018271b1 Mon Sep 17 00:00:00 2001
From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Mon, 8 Mar 2010 10:27:42 -0800
Subject: [PATCH] Configure checks for kernel build options incompatible with
 the license

Twice now I've been bitten by building agaist a kernel which is
configured such that it is incompatible with the CDDL license.  These
build failures don't occur until the linking phase at which point they
simply callout the offending symbol.  No location information can be
provided at this point so it often can be confusing what the problem is
particularly when building against a new kernel for the first time.

To help address this I've added a configure check which can be extended
over time to detect known kernel config options which if set will break
the ZFS build.  Currently I have just added CONFIG_DEBUG_LOCK_ALLOC which
makes mutex's GPL-only and is on by default in the RHEL6 alpha builds.
I know for a fact there are other similiar options which can be added
as they are encountered.
---
 META                |  2 ++
 config/kernel.m4    | 25 +++++++++++++++++++++++++
 config/zfs-build.m4 | 12 ++++--------
 config/zfs-meta.m4  |  8 ++++++++
 4 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/META b/META
index 2b06b650cd..90ea64efa1 100644
--- a/META
+++ b/META
@@ -4,3 +4,5 @@ Branch:       1.0
 Version:      0.4.7
 Release:      1
 Release-Tags: relext
+License:      CDDL
+Author:       Sun Microsystems/Oracle, Lawrence Livermore National Laboratory
diff --git a/config/kernel.m4 b/config/kernel.m4
index ae1b5e5321..9f5dd6894a 100644
--- a/config/kernel.m4
+++ b/config/kernel.m4
@@ -4,6 +4,7 @@ dnl #
 AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL
 	ZFS_AC_SPL
+	ZFS_AC_KERNEL_CONFIG
 	ZFS_AC_KERNEL_BDEV_BLOCK_DEVICE_OPERATIONS
 	ZFS_AC_KERNEL_TYPE_FMODE_T
 	ZFS_AC_KERNEL_OPEN_BDEV_EXCLUSIVE
@@ -238,6 +239,30 @@ AC_DEFUN([ZFS_AC_SPL], [
 	ZFS_AC_SPL_MODULE_SYMVERS
 ])
 
+dnl #
+dnl # There are certain kernel build options which when enabled are
+dnl # completely incompatible with non GPL kernel modules.  It is best
+dnl # to detect these at configure time and fail with a clear error
+dnl # rather than build everything and fail during linking.
+dnl #
+dnl # CONFIG_DEBUG_LOCK_ALLOC - Maps mutex_lock() to mutex_lock_nested()
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_CONFIG], [
+
+	if test "$ZFS_META_LICENSE" = CDDL; then
+		ZFS_LINUX_CONFIG([DEBUG_LOCK_ALLOC],
+		AC_MSG_ERROR([
+		*** Kernel built with CONFIG_DEBUG_LOCK_ALLOC which is
+		*** incompatible with the CDDL license.  You must rebuild
+		*** your kernel without this option.]), [])
+	fi
+
+	if test "$ZFS_META_LICENSE" = GPL; then
+		AC_DEFINE([HAVE_GPL_ONLY_SYMBOLS], [1],
+			[Define to 1 if licensed under the GPL])
+	fi
+])
+
 dnl #
 dnl # ZFS_LINUX_CONFTEST
 dnl #
diff --git a/config/zfs-build.m4 b/config/zfs-build.m4
index d2ba2977fa..a10fd2e1ef 100644
--- a/config/zfs-build.m4
+++ b/config/zfs-build.m4
@@ -1,13 +1,9 @@
 AC_DEFUN([ZFS_AC_LICENSE], [
-	AC_MSG_CHECKING([zfs license])
-	LICENSE=`grep MODULE_LICENSE module/zfs/zfs_ioctl.c | cut -f2 -d'"'`
-	AC_MSG_RESULT([$LICENSE])
-	if test "$LICENSE" = GPL; then
-		AC_DEFINE([HAVE_GPL_ONLY_SYMBOLS], [1],
-		          [Define to 1 if module is licensed under the GPL])
-	fi
+	AC_MSG_CHECKING([zfs author])
+	AC_MSG_RESULT([$ZFS_META_AUTHOR])
 
-	AC_SUBST(LICENSE)
+	AC_MSG_CHECKING([zfs license])
+	AC_MSG_RESULT([$ZFS_META_LICENSE])
 ])
 
 AC_DEFUN([ZFS_AC_DEBUG], [
diff --git a/config/zfs-meta.m4 b/config/zfs-meta.m4
index 393ced0dbe..8b3689af71 100644
--- a/config/zfs-meta.m4
+++ b/config/zfs-meta.m4
@@ -48,6 +48,14 @@ AC_DEFUN([ZFS_AC_META], [
 			AC_SUBST([ZFS_META_RELEASE])
 		fi
 
+		ZFS_META_LICENSE=_ZFS_AC_META_GETVAL([LICENSE]);
+		if test -n "$ZFS_META_LICENSE"; then
+			AC_DEFINE_UNQUOTED([ZFS_META_LICENSE], ["$ZFS_META_LICENSE"],
+				[Define the project license.]
+			)
+			AC_SUBST([ZFS_META_LICENSE])
+		fi
+
 		if test -n "$ZFS_META_NAME" -a -n "$ZFS_META_VERSION"; then
 				ZFS_META_ALIAS="$ZFS_META_NAME-$ZFS_META_VERSION"
 				test -n "$ZFS_META_RELEASE" &&