dnl #
dnl # Check for make_request_fn interface.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_MAKE_REQUEST_FN], [
	ZFS_LINUX_TEST_SRC([make_request_fn_int], [
		#include <linux/blkdev.h>
		int make_request(struct request_queue *q,
		    struct bio *bio) { return (0); }
	],[
		blk_queue_make_request(NULL, &make_request);
	])

	ZFS_LINUX_TEST_SRC([make_request_fn_void], [
		#include <linux/blkdev.h>
		void make_request(struct request_queue *q,
		    struct bio *bio) { return; }
	],[
		blk_queue_make_request(NULL, &make_request);
	])

	ZFS_LINUX_TEST_SRC([make_request_fn_blk_qc_t], [
		#include <linux/blkdev.h>
		blk_qc_t make_request(struct request_queue *q,
		    struct bio *bio) { return (BLK_QC_T_NONE); }
	],[
		blk_queue_make_request(NULL, &make_request);
	])

	ZFS_LINUX_TEST_SRC([blk_alloc_queue_request_fn], [
		#include <linux/blkdev.h>
		blk_qc_t make_request(struct request_queue *q,
		    struct bio *bio) { return (BLK_QC_T_NONE); }
	],[
		struct request_queue *q __attribute__ ((unused));
		q = blk_alloc_queue(make_request, NUMA_NO_NODE);
	])

	ZFS_LINUX_TEST_SRC([block_device_operations_submit_bio], [
		#include <linux/blkdev.h>
	],[
		struct block_device_operations o;
		o.submit_bio = NULL;
	])
])

AC_DEFUN([ZFS_AC_KERNEL_MAKE_REQUEST_FN], [
	dnl # Checked as part of the blk_alloc_queue_request_fn test
	dnl #
	dnl # Linux 5.9 API Change
	dnl # make_request_fn was moved into block_device_operations->submit_bio
	dnl #
	AC_MSG_CHECKING([whether submit_bio is member of struct block_device_operations])
	ZFS_LINUX_TEST_RESULT([block_device_operations_submit_bio], [
		AC_MSG_RESULT(yes)

		AC_DEFINE(HAVE_SUBMIT_BIO_IN_BLOCK_DEVICE_OPERATIONS, 1,
		    [submit_bio is member of struct block_device_operations])
		],[
		dnl # Checked as part of the blk_alloc_queue_request_fn test
		dnl #
		dnl # Linux 5.7 API Change
		dnl # blk_alloc_queue() expects request function.
		dnl #
		AC_MSG_CHECKING([whether blk_alloc_queue() expects request function])
		ZFS_LINUX_TEST_RESULT([blk_alloc_queue_request_fn], [
			AC_MSG_RESULT(yes)

			dnl # Checked as part of the blk_alloc_queue_request_fn test
			AC_MSG_CHECKING([whether make_request_fn() returns blk_qc_t])
			AC_MSG_RESULT(yes)

			AC_DEFINE(HAVE_BLK_ALLOC_QUEUE_REQUEST_FN, 1,
				[blk_alloc_queue() expects request function])
			AC_DEFINE(MAKE_REQUEST_FN_RET, blk_qc_t,
				[make_request_fn() return type])
			AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_QC, 1,
				[Noting that make_request_fn() returns blk_qc_t])
		],[
			AC_MSG_RESULT(no)

			dnl #
			dnl # Linux 3.2 API Change
			dnl # make_request_fn returns void.
			dnl #
			AC_MSG_CHECKING([whether make_request_fn() returns void])
			ZFS_LINUX_TEST_RESULT([make_request_fn_void], [
				AC_MSG_RESULT(yes)
				AC_DEFINE(MAKE_REQUEST_FN_RET, void,
					[make_request_fn() return type])
				AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_VOID, 1,
					[Noting that make_request_fn() returns void])
			],[
				AC_MSG_RESULT(no)

				dnl #
				dnl # Linux 4.4 API Change
				dnl # make_request_fn returns blk_qc_t.
				dnl #
				AC_MSG_CHECKING(
					[whether make_request_fn() returns blk_qc_t])
				ZFS_LINUX_TEST_RESULT([make_request_fn_blk_qc_t], [
					AC_MSG_RESULT(yes)
					AC_DEFINE(MAKE_REQUEST_FN_RET, blk_qc_t,
						[make_request_fn() return type])
					AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_QC, 1,
						[Noting that make_request_fn() ]
						[returns blk_qc_t])
				],[
					AC_MSG_RESULT(no)

					dnl #
					dnl # Legacy API
					dnl # make_request_fn returns int.
					dnl #
					AC_MSG_CHECKING(
						[whether make_request_fn() returns int])
					ZFS_LINUX_TEST_RESULT([make_request_fn_int], [
						AC_MSG_RESULT(yes)
						AC_DEFINE(MAKE_REQUEST_FN_RET, int,
							[make_request_fn() return type])
						AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_INT,
							1, [Noting that make_request_fn() ]
							[returns int])
					],[
						ZFS_LINUX_TEST_ERROR([make_request_fn])
					])
				])
			])
		])
	])
])