When checking for symbol exports, try compiling.

This patch adds a new autoconf function: SPL_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.

The only exception are:

 - AC_GET_VMALLOC_INFO, because we don't even have a public header to
include in the test case, but that's okay considering this symbol can
be ignored just fine.

- SPL_AC_DEVICE_CREATE, which is legacy API for 2.6.18 kernels.  Since
kernels this old are no longer supported it should arguably just be
removed entirely from the build system.

Note that we're also checking for the correct prototype with an actual
call, which was not the case with CHECK_SYMBOL_EXPORT. However, for
"complicated" test cases like with multiple symbol versions (e.g.
vfs_fsync), we stick with the original behavior and only check for the
function's existence.

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

config/spl-build.m4

@@ -137,7 +137,7 @@ AC_DEFUN([SPL_AC_KERNEL], [
 			sourcelink=$(readlink -f "$headersdir")
 		else
 			sourcelink=$(ls -1d /usr/src/kernels/* \
-				     /usr/src/linux-* \
+			             /usr/src/linux-* \
 			             2>/dev/null | grep -v obj | tail -1)
 		fi
 
@@ -678,8 +678,7 @@ dnl #
 dnl # SPL_CHECK_SYMBOL_EXPORT
 dnl # check symbol exported or not
 dnl #
-AC_DEFUN([SPL_CHECK_SYMBOL_EXPORT],
-	[AC_MSG_CHECKING([whether symbol $1 is exported])
+AC_DEFUN([SPL_CHECK_SYMBOL_EXPORT], [
 	grep -q -E '[[[:space:]]]$1[[[:space:]]]' \
 		$LINUX_OBJ/Module*.symvers 2>/dev/null
 	rc=$?
@@ -689,24 +688,42 @@ AC_DEFUN([SPL_CHECK_SYMBOL_EXPORT],
 			grep -q -E "EXPORT_SYMBOL.*($1)" \
 				"$LINUX_OBJ/$file" 2>/dev/null
 			rc=$?
-		        if test $rc -eq 0; then
-		                export=1
-		                break;
-		        fi
+			if test $rc -eq 0; then
+				export=1
+				break;
+			fi
 		done
-		if test $export -eq 0; then
-			AC_MSG_RESULT([no])
+		if test $export -eq 0; then :
 			$4
-		else
-			AC_MSG_RESULT([yes])
+		else :
 			$3
 		fi
-	else
-		AC_MSG_RESULT([yes])
+	else :
 		$3
 	fi
 ])
 
+dnl #
+dnl # SPL_LINUX_TRY_COMPILE_SYMBOL
+dnl # like SPL_LINUX_TRY_COMPILE, except SPL_CHECK_SYMBOL_EXPORT
+dnl # is called if not compiling for builtin
+dnl #
+AC_DEFUN([SPL_LINUX_TRY_COMPILE_SYMBOL], [
+	SPL_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
+			SPL_CHECK_SYMBOL_EXPORT([$3], [$4], [rc=0], [rc=1])
+		fi
+		if test $rc -ne 0; then :
+			$6
+		else :
+			$5
+		fi
+	fi
+])
+
 dnl #
 dnl # SPL_CHECK_SYMBOL_HEADER
 dnl # check if a symbol prototype is defined in listed headers.
@@ -717,10 +734,10 @@ AC_DEFUN([SPL_CHECK_SYMBOL_HEADER], [
 	for file in $3; do
 		grep -q "$2" "$LINUX/$file" 2>/dev/null
 		rc=$?
-	        if test $rc -eq 0; then
-	                header=1
-	                break;
-	        fi
+		if test $rc -eq 0; then
+			header=1
+			break;
+		fi
 	done
 	if test $header -eq 0; then
 		AC_MSG_RESULT([no])
@@ -991,10 +1008,18 @@ AC_DEFUN([SPL_AC_PATH_IN_NAMEIDATA],
 dnl #
 dnl # Custom SPL patch may export this system it is not required
 dnl #
-AC_DEFUN([SPL_AC_TASK_CURR], [
-	SPL_CHECK_SYMBOL_EXPORT([task_curr], [kernel/sched.c],
-		[AC_DEFINE(HAVE_TASK_CURR, 1, [task_curr() exported])],
-		[])
+AC_DEFUN([SPL_AC_TASK_CURR],
+	[AC_MSG_CHECKING([whether task_curr() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/sched.h>
+	], [
+		task_curr(NULL);
+	], [task_curr], [kernel/sched.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_TASK_CURR, 1, [task_curr() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1060,13 +1085,15 @@ dnl # 2.6.18 API change, check whether device_create() is available.
 dnl # Device_create() was introduced in 2.6.18 and depricated 
 dnl # class_device_create() which was fully removed in 2.6.26.
 dnl #
-AC_DEFUN([SPL_AC_DEVICE_CREATE], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[device_create],
-		[drivers/base/core.c],
-		[AC_DEFINE(HAVE_DEVICE_CREATE, 1,
-		[device_create() is available])],
-		[])
+AC_DEFUN([SPL_AC_DEVICE_CREATE],
+	[AC_MSG_CHECKING([whether device_create() is available])
+	SPL_CHECK_SYMBOL_EXPORT([device_create], [drivers/base/core.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_DEVICE_CREATE, 1,
+		          [device_create() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1096,25 +1123,37 @@ dnl # 2.6.13 API change, check whether class_device_create() is available.
 dnl # Class_device_create() was introduced in 2.6.13 and depricated
 dnl # class_simple_device_add() which was fully removed in 2.6.13.
 dnl #
-AC_DEFUN([SPL_AC_CLASS_DEVICE_CREATE], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[class_device_create],
-		[drivers/base/class.c],
-		[AC_DEFINE(HAVE_CLASS_DEVICE_CREATE, 1,
-		[class_device_create() is available])],
-		[])
+AC_DEFUN([SPL_AC_CLASS_DEVICE_CREATE],
+	[AC_MSG_CHECKING([whether class_device_create() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/device.h>
+	], [
+		class_device_create(NULL, NULL, 0, NULL, NULL);
+	], [class_device_create], [drivers/base/class.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_CLASS_DEVICE_CREATE, 1,
+		          [class_device_create() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
 dnl # 2.6.26 API change, set_normalized_timespec() is exported.
 dnl #
-AC_DEFUN([SPL_AC_SET_NORMALIZED_TIMESPEC_EXPORT], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[set_normalized_timespec],
-		[kernel/time.c],
-		[AC_DEFINE(HAVE_SET_NORMALIZED_TIMESPEC_EXPORT, 1,
-		[set_normalized_timespec() is available as export])],
-		[])
+AC_DEFUN([SPL_AC_SET_NORMALIZED_TIMESPEC_EXPORT],
+	[AC_MSG_CHECKING([whether set_normalized_timespec() is available as export])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/time.h>
+	], [
+		set_normalized_timespec(NULL, 0, 0);
+	], [set_normalized_timespec], [kernel/time.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_SET_NORMALIZED_TIMESPEC_EXPORT, 1,
+		          [set_normalized_timespec() is available as export])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1264,13 +1303,19 @@ dnl # 2.6.9 API change,
 dnl # check whether 'monotonic_clock()' is available it may
 dnl # be available for some archs but not others.
 dnl #
-AC_DEFUN([SPL_AC_MONOTONIC_CLOCK], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[monotonic_clock],
-		[],
-		[AC_DEFINE(HAVE_MONOTONIC_CLOCK, 1,
-		[monotonic_clock() is available])],
-		[])
+AC_DEFUN([SPL_AC_MONOTONIC_CLOCK],
+	[AC_MSG_CHECKING([whether monotonic_clock() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/timex.h>
+	], [
+		monotonic_clock();
+	], [monotonic_clock], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_MONOTONIC_CLOCK, 1,
+		          [monotonic_clock() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1384,13 +1429,19 @@ dnl #
 dnl # 2.6.18 API change,
 dnl # kallsyms_lookup_name no longer exported
 dnl #
-AC_DEFUN([SPL_AC_KALLSYMS_LOOKUP_NAME], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[kallsyms_lookup_name],
-		[],
-		[AC_DEFINE(HAVE_KALLSYMS_LOOKUP_NAME, 1,
-		[kallsyms_lookup_name() is available])],
-		[])
+AC_DEFUN([SPL_AC_KALLSYMS_LOOKUP_NAME],
+	[AC_MSG_CHECKING([whether kallsyms_lookup_name() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/kallsyms.h>
+	], [
+		kallsyms_lookup_name(NULL);
+	], [kallsyms_lookup_name], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_KALLSYMS_LOOKUP_NAME, 1,
+		          [kallsyms_lookup_name() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1400,13 +1451,15 @@ dnl # custom kernel with the *-spl-export-symbols.patch which will export
 dnl # these symbols for use.  If your already rolling a custom kernel for
 dnl # your environment this is recommended.
 dnl #
-AC_DEFUN([SPL_AC_GET_VMALLOC_INFO], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[get_vmalloc_info],
-		[],
-		[AC_DEFINE(HAVE_GET_VMALLOC_INFO, 1,
-		[get_vmalloc_info() is available])],
-		[])
+AC_DEFUN([SPL_AC_GET_VMALLOC_INFO],
+	[AC_MSG_CHECKING([whether get_vmalloc_info() is available])
+	SPL_CHECK_SYMBOL_EXPORT([get_vmalloc_info], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_GET_VMALLOC_INFO, 1,
+		          [get_vmalloc_info() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1428,7 +1481,7 @@ AC_DEFUN([SPL_AC_PGDAT_HELPERS], [
 	rc=$?
 	if test $rc -eq 0; then
 		AC_MSG_RESULT([yes])
-                AC_DEFINE(HAVE_PGDAT_HELPERS, 1, [pgdat helpers are available])
+		AC_DEFINE(HAVE_PGDAT_HELPERS, 1, [pgdat helpers are available])
 	else
 		AC_MSG_RESULT([no])
 	fi
@@ -1441,13 +1494,19 @@ dnl # custom kernel with the *-spl-export-symbols.patch which will export
 dnl # these symbols for use.  If your already rolling a custom kernel for
 dnl # your environment this is recommended.
 dnl #
-AC_DEFUN([SPL_AC_FIRST_ONLINE_PGDAT], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[first_online_pgdat],
-		[],
-		[AC_DEFINE(HAVE_FIRST_ONLINE_PGDAT, 1,
-		[first_online_pgdat() is available])],
-		[])
+AC_DEFUN([SPL_AC_FIRST_ONLINE_PGDAT],
+	[AC_MSG_CHECKING([whether first_online_pgdat() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/mmzone.h>
+	], [
+		first_online_pgdat();
+	], [first_online_pgdat], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_FIRST_ONLINE_PGDAT, 1,
+		          [first_online_pgdat() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1457,13 +1516,19 @@ dnl # custom kernel with the *-spl-export-symbols.patch which will export
 dnl # these symbols for use.  If your already rolling a custom kernel for
 dnl # your environment this is recommended.
 dnl #
-AC_DEFUN([SPL_AC_NEXT_ONLINE_PGDAT], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[next_online_pgdat],
-		[],
-		[AC_DEFINE(HAVE_NEXT_ONLINE_PGDAT, 1,
-		[next_online_pgdat() is available])],
-		[])
+AC_DEFUN([SPL_AC_NEXT_ONLINE_PGDAT],
+	[AC_MSG_CHECKING([whether next_online_pgdat() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/mmzone.h>
+	], [
+		next_online_pgdat(NULL);
+	], [next_online_pgdat], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_NEXT_ONLINE_PGDAT, 1,
+		          [next_online_pgdat() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1473,26 +1538,35 @@ dnl # custom kernel with the *-spl-export-symbols.patch which will export
 dnl # these symbols for use.  If your already rolling a custom kernel for
 dnl # your environment this is recommended.
 dnl #
-AC_DEFUN([SPL_AC_NEXT_ZONE], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[next_zone],
-		[],
-		[AC_DEFINE(HAVE_NEXT_ZONE, 1,
-		[next_zone() is available])],
-		[])
+AC_DEFUN([SPL_AC_NEXT_ZONE],
+	[AC_MSG_CHECKING([whether next_zone() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/mmzone.h>
+	], [
+		next_zone(NULL);
+	], [next_zone], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_NEXT_ZONE, 1, [next_zone() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
 dnl # 2.6.17 API change,
 dnl # See SPL_AC_PGDAT_HELPERS for details.
 dnl #
-AC_DEFUN([SPL_AC_PGDAT_LIST], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[pgdat_list],
-		[],
-		[AC_DEFINE(HAVE_PGDAT_LIST, 1,
-		[pgdat_list is available])],
-		[])
+AC_DEFUN([SPL_AC_PGDAT_LIST],
+	[AC_MSG_CHECKING([whether pgdat_list is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/topology.h>
+		pg_data_t *tmp = pgdat_list;
+	], [], [pgdat_list], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_PGDAT_LIST, 1, [pgdat_list is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1684,12 +1758,18 @@ AC_DEFUN([SPL_AC_GET_ZONE_COUNTS], [
 		AC_DEFINE(NEED_GET_ZONE_COUNTS, 1,
 		          [get_zone_counts() is needed])
 
-		SPL_CHECK_SYMBOL_EXPORT(
-			[get_zone_counts],
-			[],
-			[AC_DEFINE(HAVE_GET_ZONE_COUNTS, 1,
-			[get_zone_counts() is available])],
-			[])
+		AC_MSG_CHECKING([whether get_zone_counts() is available])
+		SPL_LINUX_TRY_COMPILE_SYMBOL([
+			#include <linux/mmzone.h>
+		], [
+			get_zone_counts(NULL, NULL, NULL);
+		], [get_zone_counts], [], [
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_GET_ZONE_COUNTS, 1,
+			          [get_zone_counts() is available])
+		], [
+			AC_MSG_RESULT(no)
+		])
 	])
 ])
 
@@ -1697,25 +1777,37 @@ dnl #
 dnl # 2.6.27 API change,
 dnl # The user_path_dir() replaces __user_walk()
 dnl #
-AC_DEFUN([SPL_AC_USER_PATH_DIR], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[user_path_at],
-		[],
-		[AC_DEFINE(HAVE_USER_PATH_DIR, 1,
-		[user_path_dir() is available])],
-		[])
+AC_DEFUN([SPL_AC_USER_PATH_DIR],
+	[AC_MSG_CHECKING([whether user_path_dir() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/fcntl.h>
+		#include <linux/namei.h>
+	], [
+		user_path_dir(NULL, NULL);
+	], [user_path_at], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_USER_PATH_DIR, 1, [user_path_dir() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
 dnl # Symbol available in RHEL kernels not in stock kernels.
 dnl #
-AC_DEFUN([SPL_AC_SET_FS_PWD], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[set_fs_pwd],
-		[],
-		[AC_DEFINE(HAVE_SET_FS_PWD, 1,
-		[set_fs_pwd() is available])],
-		[])
+AC_DEFUN([SPL_AC_SET_FS_PWD],
+	[AC_MSG_CHECKING([whether set_fs_pwd() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/spinlock.h>
+		#include <linux/fs_struct.h>
+	], [
+		(void) set_fs_pwd;
+	], [set_fs_pwd], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_SET_FS_PWD, 1, [set_fs_pwd() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1823,26 +1915,37 @@ AC_DEFUN([SPL_AC_CRED_STRUCT], [
 dnl #
 dnl # Custom SPL patch may export this symbol.
 dnl #
-AC_DEFUN([SPL_AC_GROUPS_SEARCH], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[groups_search],
-		[],
-		[AC_DEFINE(HAVE_GROUPS_SEARCH, 1,
-		[groups_search() is available])],
-		[])
+AC_DEFUN([SPL_AC_GROUPS_SEARCH],
+	[AC_MSG_CHECKING([whether groups_search() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/cred.h>
+	], [
+		groups_search(NULL, 0);
+	], [groups_search], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_GROUPS_SEARCH, 1, [groups_search() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
 dnl # 2.6.x API change,
 dnl # __put_task_struct() was exported in RHEL5 but unavailable elsewhere.
 dnl #
-AC_DEFUN([SPL_AC_PUT_TASK_STRUCT], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[__put_task_struct],
-		[],
-		[AC_DEFINE(HAVE_PUT_TASK_STRUCT, 1,
-		[__put_task_struct() is available])],
-		[])
+AC_DEFUN([SPL_AC_PUT_TASK_STRUCT],
+	[AC_MSG_CHECKING([whether __put_task_struct() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/sched.h>
+	], [
+		__put_task_struct(NULL);
+	], [__put_task_struct], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_PUT_TASK_STRUCT, 1,
+		          [__put_task_struct() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1868,25 +1971,36 @@ dnl #
 dnl # 2.6.x API change,
 dnl # kvasprintf() function added.
 dnl #
-AC_DEFUN([SPL_AC_KVASPRINTF], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[kvasprintf],
-		[],
-		[AC_DEFINE(HAVE_KVASPRINTF, 1,
-		[kvasprintf() is available])],
-		[])
+AC_DEFUN([SPL_AC_KVASPRINTF],
+	[AC_MSG_CHECKING([whether kvasprintf() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/kernel.h>
+	], [
+		kvasprintf(0, NULL, *((va_list*)NULL));
+	], [kvasprintf], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_KVASPRINTF, 1, [kvasprintf() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
 dnl # 2.6.29 API change,
 dnl # vfs_fsync() funcation added, prior to this use file_fsync().
 dnl #
-AC_DEFUN([SPL_AC_VFS_FSYNC], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[vfs_fsync],
-		[fs/sync.c],
-		[AC_DEFINE(HAVE_VFS_FSYNC, 1, [vfs_fsync() is available])],
-		[])
+AC_DEFUN([SPL_AC_VFS_FSYNC],
+	[AC_MSG_CHECKING([whether vfs_fsync() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/fs.h>
+	], [
+		(void) vfs_fsync;
+	], [vfs_fsync], [fs/sync.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_VFS_FSYNC, 1, [vfs_fsync() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1914,13 +2028,18 @@ dnl # condition.  The fixed version is exported as a symbol.  The race
 dnl # condition is fixed by acquiring sem->wait_lock, so we must not
 dnl # call that version while holding sem->wait_lock.
 dnl #
-AC_DEFUN([SPL_AC_EXPORTED_RWSEM_IS_LOCKED], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[rwsem_is_locked],
-		[lib/rwsem-spinlock.c],
-		[AC_DEFINE(RWSEM_IS_LOCKED_TAKES_WAIT_LOCK, 1,
-		[rwsem_is_locked() acquires sem->wait_lock])],
-		[])
+AC_DEFUN([SPL_AC_EXPORTED_RWSEM_IS_LOCKED],
+	[AC_MSG_CHECKING([whether rwsem_is_locked() acquires sem->wait_lock])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/rwsem.h>
+		int rwsem_is_locked(struct rw_semaphore *sem) { return 0; }
+	], [], [rwsem_is_locked], [lib/rwsem-spinlock.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(RWSEM_IS_LOCKED_TAKES_WAIT_LOCK, 1,
+		          [rwsem_is_locked() acquires sem->wait_lock])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1937,18 +2056,31 @@ dnl # of these functions are exported invalidate_inodes() can be
 dnl # safely used.
 dnl #
 AC_DEFUN([SPL_AC_KERNEL_INVALIDATE_INODES], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[invalidate_inodes],
-		[],
-		[AC_DEFINE(HAVE_INVALIDATE_INODES, 1,
-		[invalidate_inodes() is available])],
-		[])
-	SPL_CHECK_SYMBOL_EXPORT(
-		[invalidate_inodes_check],
-		[],
-		[AC_DEFINE(HAVE_INVALIDATE_INODES_CHECK, 1,
-		[invalidate_inodes_check() is available])],
-		[])
+	AC_MSG_CHECKING([whether invalidate_inodes() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/fs.h>
+	], [
+		invalidate_inodes;
+	], [invalidate_inodes], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_INVALIDATE_INODES, 1,
+		          [invalidate_inodes() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
+
+	AC_MSG_CHECKING([whether invalidate_inodes_check() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/fs.h>
+	], [
+		invalidate_inodes_check(NULL, 0);
+	], [invalidate_inodes_check], [], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_INVALIDATE_INODES_CHECK, 1,
+		          [invalidate_inodes_check() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -1987,13 +2119,19 @@ dnl # There currently exists no exposed API to partially shrink the dcache.
 dnl # The expected mechanism to shrink the cache is a registered shrinker
 dnl # which is called during memory pressure.
 dnl #
-AC_DEFUN([SPL_AC_SHRINK_DCACHE_MEMORY], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[shrink_dcache_memory],
-		[fs/dcache.c],
-		[AC_DEFINE(HAVE_SHRINK_DCACHE_MEMORY, 1,
-		[shrink_dcache_memory() is available])],
-		[])
+AC_DEFUN([SPL_AC_SHRINK_DCACHE_MEMORY],
+	[AC_MSG_CHECKING([whether shrink_dcache_memory() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/dcache.h>
+	], [
+		shrink_dcache_memory(0, 0);
+	], [shrink_dcache_memory], [fs/dcache.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_SHRINK_DCACHE_MEMORY, 1,
+		          [shrink_dcache_memory() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -2002,13 +2140,19 @@ dnl # There currently exists no exposed API to partially shrink the icache.
 dnl # The expected mechanism to shrink the cache is a registered shrinker
 dnl # which is called during memory pressure.
 dnl #
-AC_DEFUN([SPL_AC_SHRINK_ICACHE_MEMORY], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[shrink_icache_memory],
-		[fs/inode.c],
-		[AC_DEFINE(HAVE_SHRINK_ICACHE_MEMORY, 1,
-		[shrink_icache_memory() is available])],
-		[])
+AC_DEFUN([SPL_AC_SHRINK_ICACHE_MEMORY],
+	[AC_MSG_CHECKING([whether shrink_icache_memory() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/dcache.h>
+	], [
+		shrink_icache_memory(0, 0);
+	], [shrink_icache_memory], [fs/inode.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_SHRINK_ICACHE_MEMORY, 1,
+		          [shrink_icache_memory() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #
@@ -2034,13 +2178,19 @@ dnl # The kern_path_parent() symbol is no longer exported by the kernel.
 dnl # However, it remains the prefered interface and since we still have
 dnl # access to the prototype we dynamically lookup the required address.
 dnl #
-AC_DEFUN([SPL_AC_KERN_PATH_PARENT_SYMBOL], [
-	SPL_CHECK_SYMBOL_EXPORT(
-		[kern_path_parent],
-		[fs/namei.c],
-		[AC_DEFINE(HAVE_KERN_PATH_PARENT_SYMBOL, 1,
-		[kern_path_parent() is available])],
-		[])
+AC_DEFUN([SPL_AC_KERN_PATH_PARENT_SYMBOL],
+	[AC_MSG_CHECKING([whether kern_path_parent() is available])
+	SPL_LINUX_TRY_COMPILE_SYMBOL([
+		#include <linux/namei.h>
+	], [
+		kern_path_parent(NULL, NULL);
+	], [kern_path_parent], [fs/namei.c], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_KERN_PATH_PARENT_SYMBOL, 1,
+		          [kern_path_parent() is available])
+	], [
+		AC_MSG_RESULT(no)
+	])
 ])
 
 dnl #

spl_config.h.in

@@ -210,7 +210,7 @@
 /* Define to 1 if you have the <sys/types.h> header file. */
 #undef HAVE_SYS_TYPES_H
 
-/* task_curr() exported */
+/* task_curr() is available */
 #undef HAVE_TASK_CURR
 
 /* timespec_sub() is available */