Make CONFIG_PREEMPT Fatal

Until support is added for preemptible kernels detect this at
configure time and make it fatal.  Otherwise, it is possible to
have a successful build and kernel modules with flakey behavior.

config/spl-build.m4

@@ -8,6 +8,7 @@
 
 AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
 	SPL_AC_KERNEL
+	SPL_AC_KERNEL_CONFIG
 
 	if test "${LINUX_OBJ}" != "${LINUX}"; then
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"
@@ -190,6 +191,13 @@ AC_DEFUN([SPL_AC_KERNEL], [
 	SPL_AC_MODULE_SYMVERS
 ])
 
+AC_DEFUN([SPL_AC_KERNEL_CONFIG], [
+	SPL_LINUX_CONFIG([PREEMPT],
+		AC_MSG_ERROR([
+		*** Kernel built with CONFIG_PREEMPT which is not supported.
+		** You must rebuild your kernel without this option.]), [])
+])
+
 dnl #
 dnl # Explicitly check for gawk, we require it for the the usermode
 dnl # helper.  For some reason the standard awk command does not

configure

@@ -11793,6 +11793,79 @@ $as_echo "$LINUX_SYMBOLS" >&6; }
 
 
 
+	{ $as_echo "$as_me:$LINENO: checking whether Linux was built with CONFIG_PREEMPT" >&5
+$as_echo_n "checking whether Linux was built with CONFIG_PREEMPT... " >&6; }
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#ifndef AUTOCONF_INCLUDED
+		#include <linux/config.h>
+		#endif
+
+int
+main (void)
+{
+
+		#ifndef CONFIG_PREEMPT
+		#error CONFIG_PREEMPT not #defined
+		#endif
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build
+	echo "obj-m := conftest.o" >build/Makefile
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+		{ { $as_echo "$as_me:$LINENO: error:
+		*** Kernel built with CONFIG_PREEMPT which is not supported.
+		** You must rebuild your kernel without this option." >&5
+$as_echo "$as_me: error:
+		*** Kernel built with CONFIG_PREEMPT which is not supported.
+		** You must rebuild your kernel without this option." >&2;}
+   { (exit 1); exit 1; }; }
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+		{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+
+
+fi
+
+	rm -Rf build
+
+
+
+
+
 	if test "${LINUX_OBJ}" != "${LINUX}"; then
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"
 	fi
@@ -15528,6 +15601,79 @@ $as_echo "$LINUX_SYMBOLS" >&6; }
 
 
 
+	{ $as_echo "$as_me:$LINENO: checking whether Linux was built with CONFIG_PREEMPT" >&5
+$as_echo_n "checking whether Linux was built with CONFIG_PREEMPT... " >&6; }
+
+
+cat confdefs.h - <<_ACEOF >conftest.c
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+
+		#ifndef AUTOCONF_INCLUDED
+		#include <linux/config.h>
+		#endif
+
+int
+main (void)
+{
+
+		#ifndef CONFIG_PREEMPT
+		#error CONFIG_PREEMPT not #defined
+		#endif
+
+  ;
+  return 0;
+}
+
+_ACEOF
+
+
+	rm -Rf build && mkdir -p build
+	echo "obj-m := conftest.o" >build/Makefile
+	if { ac_try='cp conftest.c build && make modules -C $LINUX_OBJ EXTRA_CFLAGS="-Werror-implicit-function-declaration $EXTRA_KCFLAGS" $ARCH_UM M=$PWD/build'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } >/dev/null && { ac_try='test -s build/conftest.o'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+		{ $as_echo "$as_me:$LINENO: result: yes" >&5
+$as_echo "yes" >&6; }
+		{ { $as_echo "$as_me:$LINENO: error:
+		*** Kernel built with CONFIG_PREEMPT which is not supported.
+		** You must rebuild your kernel without this option." >&5
+$as_echo "$as_me: error:
+		*** Kernel built with CONFIG_PREEMPT which is not supported.
+		** You must rebuild your kernel without this option." >&2;}
+   { (exit 1); exit 1; }; }
+
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+		{ $as_echo "$as_me:$LINENO: result: no" >&5
+$as_echo "no" >&6; }
+
+
+
+
+fi
+
+	rm -Rf build
+
+
+
+
+
 	if test "${LINUX_OBJ}" != "${LINUX}"; then
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"
 	fi