mirror_zfs/config/kernel-bio-rw-syncio.m4
Brian Behlendorf 675de5aa37 Linux 2.6.36 compat, synchronous bio flag
The name of the flag used to mark a bio as synchronous has changed
again in the 2.6.36 kernel due to the unification of the BIO_RW_*
and REQ_* flags.  The new flag is called REQ_SYNC.  To simplify
checking this flag I have introduced the vdev_disk_dio_is_sync()
helper function.  Based on the results of several new autoconf
tests it uses the correct mask to check for a synchronous bio.

Preferred interface for flagging a synchronous bio:
  2.6.12-2.6.29: BIO_RW_SYNC
  2.6.30-2.6.35: BIO_RW_SYNCIO
  2.6.36-2.6.xx: REQ_SYNC
2010-11-10 17:00:33 -08:00

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dnl #
dnl # Preferred interface for flagging a synchronous bio:
dnl # 2.6.12-2.6.29: BIO_RW_SYNC
dnl # 2.6.30-2.6.35: BIO_RW_SYNCIO
dnl # 2.6.36-2.6.xx: REQ_SYNC
dnl #
AC_DEFUN([ZFS_AC_KERNEL_BIO_RW_SYNC], [
AC_MSG_CHECKING([whether BIO_RW_SYNC is defined])
ZFS_LINUX_TRY_COMPILE([
#include <linux/bio.h>
],[
int flags;
flags = BIO_RW_SYNC;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_BIO_RW_SYNC, 1, [BIO_RW_SYNC is defined])
],[
AC_MSG_RESULT(no)
])
])
AC_DEFUN([ZFS_AC_KERNEL_BIO_RW_SYNCIO], [
AC_MSG_CHECKING([whether BIO_RW_SYNCIO is defined])
ZFS_LINUX_TRY_COMPILE([
#include <linux/bio.h>
],[
int flags;
flags = BIO_RW_SYNCIO;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_BIO_RW_SYNCIO, 1, [BIO_RW_SYNCIO is defined])
],[
AC_MSG_RESULT(no)
])
])
AC_DEFUN([ZFS_AC_KERNEL_REQ_SYNC], [
AC_MSG_CHECKING([whether REQ_SYNC is defined])
ZFS_LINUX_TRY_COMPILE([
#include <linux/bio.h>
],[
int flags;
flags = REQ_SYNC;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_REQ_SYNC, 1, [REQ_SYNC is defined])
],[
AC_MSG_RESULT(no)
])
])