]> git.proxmox.com Git - mirror_spl.git/blobdiff - config/spl-build.m4
Cleanly support debug packages
[mirror_spl.git] / config / spl-build.m4
index f50e1757fb63e5b8c73f1331be3b7adece2ae8d9..eee950c6704e19621a355f921f1013b54ffe3c3e 100644 (file)
@@ -1,40 +1,39 @@
-dnl #
-dnl # Default SPL kernel configuration
-dnl #
+###############################################################################
+# Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+# Copyright (C) 2007 The Regents of the University of California.
+# Written by Brian Behlendorf <behlendorf1@llnl.gov>.
+###############################################################################
+# SPL_AC_CONFIG_KERNEL: Default SPL kernel configuration.
+###############################################################################
+
 AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
        SPL_AC_KERNEL
-
-       dnl # Kernel build make options
-       dnl # KERNELMAKE_PARAMS="V=1"   # Enable verbose module build
-       KERNELMAKE_PARAMS="V=1"
-
-       dnl # -Wall -fno-strict-aliasing -Wstrict-prototypes and other
-       dnl # compiler options are added by the kernel build system.
-       abs_srcdir=`readlink -f ${srcdir}`
-       KERNELCPPFLAGS="$KERNELCPPFLAGS -Wstrict-prototypes -Werror"
-       KERNELCPPFLAGS="$KERNELCPPFLAGS -I${abs_srcdir} -I${abs_srcdir}/include"
+       SPL_AC_KERNEL_CONFIG
 
        if test "${LINUX_OBJ}" != "${LINUX}"; then
                KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"
        fi
-
        AC_SUBST(KERNELMAKE_PARAMS)
+
+       KERNELCPPFLAGS="$KERNELCPPFLAGS -Wstrict-prototypes"
        AC_SUBST(KERNELCPPFLAGS)
 
        SPL_AC_DEBUG
+       SPL_AC_DEBUG_LOG
        SPL_AC_DEBUG_KMEM
        SPL_AC_DEBUG_KMEM_TRACKING
        SPL_AC_ATOMIC_SPINLOCK
-       SPL_AC_TYPE_UINTPTR_T
-       SPL_AC_TYPE_ATOMIC64_T
        SPL_AC_TYPE_ATOMIC64_CMPXCHG
        SPL_AC_TYPE_ATOMIC64_XCHG
+       SPL_AC_TYPE_UINTPTR_T
        SPL_AC_3ARGS_INIT_WORK
        SPL_AC_2ARGS_REGISTER_SYSCTL
        SPL_AC_SET_SHRINKER
+       SPL_AC_3ARGS_SHRINKER_CALLBACK
        SPL_AC_PATH_IN_NAMEIDATA
        SPL_AC_TASK_CURR
        SPL_AC_CTL_UNNUMBERED
+       SPL_AC_CTL_NAME
        SPL_AC_FLS64
        SPL_AC_DEVICE_CREATE
        SPL_AC_5ARGS_DEVICE_CREATE
@@ -50,9 +49,8 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
        SPL_AC_MONOTONIC_CLOCK
        SPL_AC_INODE_I_MUTEX
        SPL_AC_MUTEX_OWNER
+       SPL_AC_MUTEX_OWNER_TASK_STRUCT
        SPL_AC_MUTEX_LOCK_NESTED
-       SPL_AC_DIV64_64
-       SPL_AC_DIV64_U64
        SPL_AC_3ARGS_ON_EACH_CPU
        SPL_AC_KALLSYMS_LOOKUP_NAME
        SPL_AC_GET_VMALLOC_INFO
@@ -66,13 +64,29 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
        SPL_AC_ZONE_STAT_ITEM_INACTIVE
        SPL_AC_ZONE_STAT_ITEM_ACTIVE
        SPL_AC_GET_ZONE_COUNTS
+       SPL_AC_USER_PATH_DIR
        SPL_AC_SET_FS_PWD
        SPL_AC_2ARGS_SET_FS_PWD
        SPL_AC_2ARGS_VFS_UNLINK
        SPL_AC_4ARGS_VFS_RENAME
+       SPL_AC_VFS_FSYNC
+       SPL_AC_2ARGS_VFS_FSYNC
+       SPL_AC_FS_STRUCT_SPINLOCK
        SPL_AC_CRED_STRUCT
        SPL_AC_GROUPS_SEARCH
        SPL_AC_PUT_TASK_STRUCT
+       SPL_AC_5ARGS_PROC_HANDLER
+       SPL_AC_KVASPRINTF
+       SPL_AC_EXPORTED_RWSEM_IS_LOCKED
+       SPL_AC_KERNEL_INVALIDATE_INODES
+       SPL_AC_KERNEL_2ARGS_INVALIDATE_INODES
+       SPL_AC_SHRINK_DCACHE_MEMORY
+       SPL_AC_SHRINK_ICACHE_MEMORY
+       SPL_AC_KERN_PATH_PARENT_HEADER
+       SPL_AC_KERN_PATH_PARENT_SYMBOL
+       SPL_AC_2ARGS_ZLIB_DEFLATE_WORKSPACESIZE
+       SPL_AC_SHRINK_CONTROL_STRUCT
+       SPL_AC_RWSEM_SPINLOCK_IS_RAW
 ])
 
 AC_DEFUN([SPL_AC_MODULE_SYMVERS], [
@@ -84,6 +98,14 @@ AC_DEFUN([SPL_AC_MODULE_SYMVERS], [
                else
                        LINUX_SYMBOLS=Module.symvers
                fi
+
+               if ! test -f "$LINUX_OBJ/$LINUX_SYMBOLS"; then
+                       AC_MSG_ERROR([
+       *** Please make sure the kernel devel package for your distribution
+       *** is installed.  If your building with a custom kernel make sure the
+       *** kernel is configured, built, and the '--with-linux=PATH' configure
+       *** option refers to the location of the kernel source.])
+               fi
        else
                LINUX_SYMBOLS=NONE
        fi
@@ -104,16 +126,26 @@ AC_DEFUN([SPL_AC_KERNEL], [
 
        AC_MSG_CHECKING([kernel source directory])
        if test -z "$kernelsrc"; then
-               sourcelink=`ls -1d /usr/src/kernels/* /usr/src/linux-* \
-                            2>/dev/null | grep -v obj | tail -1`
+               if test -e "/lib/modules/$(uname -r)/source"; then
+                       headersdir="/lib/modules/$(uname -r)/source"
+                       sourcelink=$(readlink -f "$headersdir")
+               elif test -e "/lib/modules/$(uname -r)/build"; then
+                       headersdir="/lib/modules/$(uname -r)/build"
+                       sourcelink=$(readlink -f "$headersdir")
+               else
+                       sourcelink=$(ls -1d /usr/src/kernels/* \
+                                    /usr/src/linux-* \
+                                    2>/dev/null | grep -v obj | tail -1)
+               fi
 
-               if test -e ${sourcelink}; then
+               if test -n "$sourcelink" && test -e ${sourcelink}; then
                        kernelsrc=`readlink -f ${sourcelink}`
                else
                        AC_MSG_RESULT([Not found])
                        AC_MSG_ERROR([
-                       *** Please specify the location of the kernel source
-                       *** with the '--with-linux=PATH' option])
+       *** Please make sure the kernel devel package for your distribution
+       *** is installed then try again.  If that fails you can specify the
+       *** location of the kernel source with the '--with-linux=PATH' option.])
                fi
        else
                if test "$kernelsrc" = "NONE"; then
@@ -124,12 +156,14 @@ AC_DEFUN([SPL_AC_KERNEL], [
        AC_MSG_RESULT([$kernelsrc])
        AC_MSG_CHECKING([kernel build directory])
        if test -z "$kernelbuild"; then
-               if test -d ${kernelsrc}-obj/`arch`/`arch`; then
-                       kernelbuild=${kernelsrc}-obj/`arch`/`arch`
-               elif test -d ${kernelsrc}-obj/`arch`/default; then
-                       kernelbuild=${kernelsrc}-obj/`arch`/default
-               elif test -d `dirname ${kernelsrc}`/build-`arch`; then
-                       kernelbuild=`dirname ${kernelsrc}`/build-`arch`
+               if test -e "/lib/modules/$(uname -r)/build"; then
+                       kernelbuild=`readlink -f /lib/modules/$(uname -r)/build`
+               elif test -d ${kernelsrc}-obj/${target_cpu}/${target_cpu}; then
+                       kernelbuild=${kernelsrc}-obj/${target_cpu}/${target_cpu}
+               elif test -d ${kernelsrc}-obj/${target_cpu}/default; then
+                       kernelbuild=${kernelsrc}-obj/${target_cpu}/default
+               elif test -d `dirname ${kernelsrc}`/build-${target_cpu}; then
+                       kernelbuild=`dirname ${kernelsrc}`/build-${target_cpu}
                else
                        kernelbuild=${kernelsrc}
                fi
@@ -137,28 +171,30 @@ AC_DEFUN([SPL_AC_KERNEL], [
        AC_MSG_RESULT([$kernelbuild])
 
        AC_MSG_CHECKING([kernel source version])
-       if test -r $kernelbuild/include/linux/version.h && 
-               fgrep -q UTS_RELEASE $kernelbuild/include/linux/version.h; then
-
-               kernsrcver=`(echo "#include <linux/version.h>"; 
-                            echo "kernsrcver=UTS_RELEASE") | 
-                            cpp -I $kernelbuild/include |
-                            grep "^kernsrcver=" | cut -d \" -f 2`
-
-       elif test -r $kernelbuild/include/linux/utsrelease.h && 
-               fgrep -q UTS_RELEASE $kernelbuild/include/linux/utsrelease.h; then
+       utsrelease1=$kernelbuild/include/linux/version.h
+       utsrelease2=$kernelbuild/include/linux/utsrelease.h
+       utsrelease3=$kernelbuild/include/generated/utsrelease.h
+       if test -r $utsrelease1 && fgrep -q UTS_RELEASE $utsrelease1; then
+               utsrelease=linux/version.h
+       elif test -r $utsrelease2 && fgrep -q UTS_RELEASE $utsrelease2; then
+               utsrelease=linux/utsrelease.h
+       elif test -r $utsrelease3 && fgrep -q UTS_RELEASE $utsrelease3; then
+               utsrelease=generated/utsrelease.h
+       fi
 
-               kernsrcver=`(echo "#include <linux/utsrelease.h>"; 
+       if test "$utsrelease"; then
+               kernsrcver=`(echo "#include <$utsrelease>";
                             echo "kernsrcver=UTS_RELEASE") | 
                             cpp -I $kernelbuild/include |
                             grep "^kernsrcver=" | cut -d \" -f 2`
-       fi
 
-       if test -z "$kernsrcver"; then
+               if test -z "$kernsrcver"; then
+                       AC_MSG_RESULT([Not found])
+                       AC_MSG_ERROR([*** Cannot determine kernel version.])
+               fi
+       else
                AC_MSG_RESULT([Not found])
-               AC_MSG_ERROR([
-               *** Cannot determine the version of the linux kernel source.
-               *** Please prepare the kernel before running this script])
+               AC_MSG_ERROR([*** Cannot find UTS_RELEASE definition.])
        fi
 
        AC_MSG_RESULT([$kernsrcver])
@@ -174,11 +210,217 @@ 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 # Default SPL user configuration
 dnl #
 AC_DEFUN([SPL_AC_CONFIG_USER], [])
 
+dnl #
+dnl # Check for rpm+rpmbuild to build RPM packages.  If these tools
+dnl # are missing it is non-fatal but you will not be able to build
+dnl # RPM packages and will be warned if you try too.
+dnl #
+AC_DEFUN([SPL_AC_RPM], [
+       RPM=rpm
+       RPMBUILD=rpmbuild
+
+       AC_MSG_CHECKING([whether $RPM is available])
+       AS_IF([tmp=$($RPM --version 2>/dev/null)], [
+               RPM_VERSION=$(echo $tmp | $AWK '/RPM/ { print $[3] }')
+               HAVE_RPM=yes
+               AC_MSG_RESULT([$HAVE_RPM ($RPM_VERSION)])
+       ],[
+               HAVE_RPM=no
+               AC_MSG_RESULT([$HAVE_RPM])
+       ])
+
+       AC_MSG_CHECKING([whether $RPMBUILD is available])
+       AS_IF([tmp=$($RPMBUILD --version 2>/dev/null)], [
+               RPMBUILD_VERSION=$(echo $tmp | $AWK '/RPM/ { print $[3] }')
+               HAVE_RPMBUILD=yes
+               AC_MSG_RESULT([$HAVE_RPMBUILD ($RPMBUILD_VERSION)])
+       ],[
+               HAVE_RPMBUILD=no
+               AC_MSG_RESULT([$HAVE_RPMBUILD])
+       ])
+
+       AC_SUBST(HAVE_RPM)
+       AC_SUBST(RPM)
+       AC_SUBST(RPM_VERSION)
+
+       AC_SUBST(HAVE_RPMBUILD)
+       AC_SUBST(RPMBUILD)
+       AC_SUBST(RPMBUILD_VERSION)
+])
+
+dnl #
+dnl # Check for dpkg+dpkg-buildpackage to build DEB packages.  If these
+dnl # tools are missing it is non-fatal but you will not be able to build
+dnl # DEB packages and will be warned if you try too.
+dnl #
+AC_DEFUN([SPL_AC_DPKG], [
+       DPKG=dpkg
+       DPKGBUILD=dpkg-buildpackage
+
+       AC_MSG_CHECKING([whether $DPKG is available])
+       AS_IF([tmp=$($DPKG --version 2>/dev/null)], [
+               DPKG_VERSION=$(echo $tmp | $AWK '/Debian/ { print $[7] }')
+               HAVE_DPKG=yes
+               AC_MSG_RESULT([$HAVE_DPKG ($DPKG_VERSION)])
+       ],[
+               HAVE_DPKG=no
+               AC_MSG_RESULT([$HAVE_DPKG])
+       ])
+
+       AC_MSG_CHECKING([whether $DPKGBUILD is available])
+       AS_IF([tmp=$($DPKGBUILD --version 2>/dev/null)], [
+               DPKGBUILD_VERSION=$(echo $tmp | \
+                   $AWK '/Debian/ { print $[4] }' | cut -f-4 -d'.')
+               HAVE_DPKGBUILD=yes
+               AC_MSG_RESULT([$HAVE_DPKGBUILD ($DPKGBUILD_VERSION)])
+       ],[
+               HAVE_DPKGBUILD=no
+               AC_MSG_RESULT([$HAVE_DPKGBUILD])
+       ])
+
+       AC_SUBST(HAVE_DPKG)
+       AC_SUBST(DPKG)
+       AC_SUBST(DPKG_VERSION)
+
+       AC_SUBST(HAVE_DPKGBUILD)
+       AC_SUBST(DPKGBUILD)
+       AC_SUBST(DPKGBUILD_VERSION)
+])
+
+dnl #
+dnl # Check for pacman+makepkg to build Arch Linux packages.  If these
+dnl # tools are missing it is non-fatal but you will not be able to
+dnl # build Arch Linux packages and will be warned if you try too.
+dnl #
+AC_DEFUN([SPL_AC_PACMAN], [
+       PACMAN=pacman
+       MAKEPKG=makepkg
+
+       AC_MSG_CHECKING([whether $PACMAN is available])
+       tmp=$($PACMAN --version 2>/dev/null)
+       AS_IF([test -n "$tmp"], [
+               PACMAN_VERSION=$(echo $tmp |
+                                $AWK '/Pacman/ { print $[3] }' |
+                                $SED 's/^v//')
+               HAVE_PACMAN=yes
+               AC_MSG_RESULT([$HAVE_PACMAN ($PACMAN_VERSION)])
+       ],[
+               HAVE_PACMAN=no
+               AC_MSG_RESULT([$HAVE_PACMAN])
+       ])
+
+       AC_MSG_CHECKING([whether $MAKEPKG is available])
+       tmp=$($MAKEPKG --version 2>/dev/null)
+       AS_IF([test -n "$tmp"], [
+               MAKEPKG_VERSION=$(echo $tmp | $AWK '/makepkg/ { print $[3] }')
+               HAVE_MAKEPKG=yes
+               AC_MSG_RESULT([$HAVE_MAKEPKG ($MAKEPKG_VERSION)])
+       ],[
+               HAVE_MAKEPKG=no
+               AC_MSG_RESULT([$HAVE_MAKEPKG])
+       ])
+
+       AC_SUBST(HAVE_PACMAN)
+       AC_SUBST(PACMAN)
+       AC_SUBST(PACMAN_VERSION)
+
+       AC_SUBST(HAVE_MAKEPKG)
+       AC_SUBST(MAKEPKG)
+       AC_SUBST(MAKEPKG_VERSION)
+])
+
+dnl #
+dnl # Until native packaging for various different packing systems
+dnl # can be added the least we can do is attempt to use alien to
+dnl # convert the RPM packages to the needed package type.  This is
+dnl # a hack but so far it has worked reasonable well.
+dnl #
+AC_DEFUN([SPL_AC_ALIEN], [
+       ALIEN=alien
+
+       AC_MSG_CHECKING([whether $ALIEN is available])
+       AS_IF([tmp=$($ALIEN --version 2>/dev/null)], [
+               ALIEN_VERSION=$(echo $tmp | $AWK '{ print $[3] }')
+               HAVE_ALIEN=yes
+               AC_MSG_RESULT([$HAVE_ALIEN ($ALIEN_VERSION)])
+       ],[
+               HAVE_ALIEN=no
+               AC_MSG_RESULT([$HAVE_ALIEN])
+       ])
+
+       AC_SUBST(HAVE_ALIEN)
+       AC_SUBST(ALIEN)
+       AC_SUBST(ALIEN_VERSION)
+])
+
+dnl #
+dnl # Using the VENDOR tag from config.guess set the default
+dnl # package type for 'make pkg': (rpm | deb | tgz)
+dnl #
+AC_DEFUN([SPL_AC_DEFAULT_PACKAGE], [
+       AC_MSG_CHECKING([linux distribution])
+       if test -f /etc/redhat-release ; then
+               VENDOR=redhat ;
+       elif test -f /etc/fedora-release ; then
+               VENDOR=fedora ;
+       elif test -f /etc/arch-release ; then
+               VENDOR=arch ;
+       elif test -f /etc/lsb-release ; then
+               VENDOR=ubuntu ;
+       elif test -f /etc/debian_version ; then
+               VENDOR=debian ;
+       elif test -f /etc/SuSE-release ; then
+               VENDOR=sles ;
+       elif test -f /etc/slackware-version ; then
+               VENDOR=slackware ;
+       elif test -f /etc/gentoo-release ; then
+               VENDOR=gentoo ;
+       else
+               VENDOR= ;
+       fi
+       AC_MSG_RESULT([$VENDOR])
+       AC_SUBST(VENDOR)
+
+       AC_MSG_CHECKING([default package type])
+       case "$VENDOR" in
+               fedora)     DEFAULT_PACKAGE=rpm ;;
+               redhat)     DEFAULT_PACKAGE=rpm ;;
+               sles)       DEFAULT_PACKAGE=rpm ;;
+               ubuntu)     DEFAULT_PACKAGE=deb ;;
+               debian)     DEFAULT_PACKAGE=deb ;;
+               slackware)  DEFAULT_PACKAGE=tgz ;;
+               arch)       DEFAULT_PACKAGE=arch;;
+               *)          DEFAULT_PACKAGE=rpm ;;
+       esac
+
+       AC_MSG_RESULT([$DEFAULT_PACKAGE])
+       AC_SUBST(DEFAULT_PACKAGE)
+])
+
+dnl #
+dnl # Default SPL user configuration
+dnl #
+AC_DEFUN([SPL_AC_PACKAGE], [
+       SPL_AC_DEFAULT_PACKAGE
+       SPL_AC_RPM
+       SPL_AC_DPKG
+       SPL_AC_ALIEN
+
+       AS_IF([test "$VENDOR" = "arch"], [SPL_AC_PACMAN])
+])
+
 AC_DEFUN([SPL_AC_LICENSE], [
        AC_MSG_CHECKING([spl license])
        LICENSE=GPL
@@ -191,7 +433,7 @@ AC_DEFUN([SPL_AC_CONFIG], [
         SPL_CONFIG=all
         AC_ARG_WITH([config],
                 AS_HELP_STRING([--with-config=CONFIG],
-                [Config file 'kernel|user|all']),
+                [Config file 'kernel|user|all|srpm']),
                 [SPL_CONFIG="$withval"])
 
         AC_MSG_CHECKING([spl config])
@@ -203,10 +445,11 @@ AC_DEFUN([SPL_AC_CONFIG], [
                 user)   SPL_AC_CONFIG_USER   ;;
                 all)    SPL_AC_CONFIG_KERNEL
                         SPL_AC_CONFIG_USER   ;;
+               srpm)                        ;;
                 *)
                 AC_MSG_RESULT([Error!])
                 AC_MSG_ERROR([Bad value "$SPL_CONFIG" for --with-config,
-                              user kernel|user|all]) ;;
+                              user kernel|user|all|srpm]) ;;
         esac
 
         AM_CONDITIONAL([CONFIG_USER],
@@ -222,6 +465,7 @@ dnl # Enable if the SPL should be compiled with internal debugging enabled.
 dnl # By default this support is disabled.
 dnl #
 AC_DEFUN([SPL_AC_DEBUG], [
+       AC_MSG_CHECKING([whether debugging is enabled])
        AC_ARG_ENABLE([debug],
                [AS_HELP_STRING([--enable-debug],
                [Enable generic debug support @<:@default=no@:>@])],
@@ -229,13 +473,54 @@ AC_DEFUN([SPL_AC_DEBUG], [
                [enable_debug=no])
 
        AS_IF([test "x$enable_debug" = xyes],
-               [KERNELCPPFLAGS="${KERNELCPPFLAGS} -DDEBUG"],
-               [KERNELCPPFLAGS="${KERNELCPPFLAGS} -DNDEBUG"])
+       [
+               KERNELCPPFLAGS="${KERNELCPPFLAGS} -DDEBUG -Werror"
+               DEBUG_CFLAGS="-DDEBUG -Werror"
+               DEBUG_SPL="_with_debug"
+       ], [
+               KERNELCPPFLAGS="${KERNELCPPFLAGS} -DNDEBUG"
+               DEBUG_CFLAGS="-DNDEBUG"
+               DEBUG_SPL="_without_debug"
+       ])
 
-       AC_MSG_CHECKING([whether debugging is enabled])
+       AC_SUBST(DEBUG_CFLAGS)
+       AC_SUBST(DEBUG_SPL)
        AC_MSG_RESULT([$enable_debug])
 ])
 
+dnl #
+dnl # Enabled by default it provides a basic debug log infrastructure.
+dnl # Each subsystem registers itself with a name and logs messages
+dnl # using predefined types.  If the debug mask it set to allow the
+dnl # message type it will be written to the internal log.  The log
+dnl # can be dumped to a file by echoing 1 to the 'dump' proc entry,
+dnl # after dumping the log it must be decoded using the spl utility.
+dnl #
+dnl # echo 1 >/proc/sys/kernel/spl/debug/dump
+dnl # spl /tmp/spl-log.xxx.yyy /tmp/spl-log.xxx.yyy.txt
+dnl #
+AC_DEFUN([SPL_AC_DEBUG_LOG], [
+       AC_ARG_ENABLE([debug-log],
+               [AS_HELP_STRING([--enable-debug-log],
+               [Enable basic debug logging @<:@default=yes@:>@])],
+               [],
+               [enable_debug_log=yes])
+
+       AS_IF([test "x$enable_debug_log" = xyes],
+       [
+               KERNELCPPFLAGS="${KERNELCPPFLAGS} -DDEBUG_LOG"
+               DEBUG_LOG="_with_debug_log"
+               AC_DEFINE([DEBUG_LOG], [1],
+               [Define to 1 to enable basic debug logging])
+       ], [
+               DEBUG_LOG="_without_debug_log"
+       ])
+
+       AC_SUBST(DEBUG_LOG)
+       AC_MSG_CHECKING([whether basic debug logging is enabled])
+       AC_MSG_RESULT([$enable_debug_log])
+])
+
 dnl #
 dnl # Enabled by default it provides a minimal level of memory tracking.
 dnl # A total count of bytes allocated is kept for each alloc and free.
@@ -251,10 +536,16 @@ AC_DEFUN([SPL_AC_DEBUG_KMEM], [
                [enable_debug_kmem=yes])
 
        AS_IF([test "x$enable_debug_kmem" = xyes],
-               [AC_DEFINE([DEBUG_KMEM], [1],
+       [
+               KERNELCPPFLAGS="${KERNELCPPFLAGS} -DDEBUG_KMEM"
+               DEBUG_KMEM="_with_debug_kmem"
+               AC_DEFINE([DEBUG_KMEM], [1],
                [Define to 1 to enable basic kmem accounting])
-               KERNELCPPFLAGS="${KERNELCPPFLAGS} -DDEBUG_KMEM"])
+       ], [
+               DEBUG_KMEM="_without_debug_kmem"
+       ])
 
+       AC_SUBST(DEBUG_KMEM)
        AC_MSG_CHECKING([whether basic kmem accounting is enabled])
        AC_MSG_RESULT([$enable_debug_kmem])
 ])
@@ -276,40 +567,25 @@ AC_DEFUN([SPL_AC_DEBUG_KMEM_TRACKING], [
                [enable_debug_kmem_tracking=no])
 
        AS_IF([test "x$enable_debug_kmem_tracking" = xyes],
-               [AC_DEFINE([DEBUG_KMEM_TRACKING], [1],
+       [
+               KERNELCPPFLAGS="${KERNELCPPFLAGS} -DDEBUG_KMEM_TRACKING"
+               DEBUG_KMEM_TRACKING="_with_debug_kmem_tracking"
+               AC_DEFINE([DEBUG_KMEM_TRACKING], [1],
                [Define to 1 to enable detailed kmem tracking])
-               KERNELCPPFLAGS="${KERNELCPPFLAGS} -DDEBUG_KMEM_TRACKING"])
+       ], [
+               DEBUG_KMEM_TRACKING="_without_debug_kmem_tracking"
+       ])
 
+       AC_SUBST(DEBUG_KMEM_TRACKING)
        AC_MSG_CHECKING([whether detailed kmem tracking is enabled])
        AC_MSG_RESULT([$enable_debug_kmem_tracking])
 ])
 
-dnl #
-dnl # Use the atomic implemenation based on global spinlocks.  This
-dnl # should never be needed, however it has been left in place as
-dnl # a fallback option in case problems are observed with directly
-dnl # mapping to the native Linux atomic operations.
-dnl #
-AC_DEFUN([SPL_AC_ATOMIC_SPINLOCK], [
-       AC_ARG_ENABLE([atomic-spinlocks],
-               [AS_HELP_STRING([--enable-atomic-spinlocks],
-               [Atomic types use spinlocks @<:@default=no@:>@])],
-               [],
-               [enable_atomic_spinlocks=no])
-
-       AS_IF([test "x$enable_atomic_spinlocks" = xyes],
-               [AC_DEFINE([ATOMIC_SPINLOCK], [1],
-               [Atomic types use spinlocks])])
-
-       AC_MSG_CHECKING([whether atomic types use spinlocks])
-       AC_MSG_RESULT([$enable_atomic_spinlocks])
-])
-
 dnl #
 dnl # SPL_LINUX_CONFTEST
 dnl #
 AC_DEFUN([SPL_LINUX_CONFTEST], [
-cat >conftest.c <<_ACEOF
+cat confdefs.h - <<_ACEOF >conftest.c
 $1
 _ACEOF
 ])
@@ -362,9 +638,7 @@ dnl #
 AC_DEFUN([SPL_LINUX_CONFIG],
        [AC_MSG_CHECKING([whether Linux was built with CONFIG_$1])
        SPL_LINUX_TRY_COMPILE([
-               #ifndef AUTOCONF_INCLUDED
-               #include <linux/config.h>
-               #endif
+               #include <linux/module.h>
        ],[
                #ifndef CONFIG_$1
                #error CONFIG_$1 not #defined
@@ -411,6 +685,30 @@ AC_DEFUN([SPL_CHECK_SYMBOL_EXPORT],
        fi
 ])
 
+dnl #
+dnl # SPL_CHECK_SYMBOL_HEADER
+dnl # check if a symbol prototype is defined in listed headers.
+dnl #
+AC_DEFUN([SPL_CHECK_SYMBOL_HEADER], [
+       AC_MSG_CHECKING([whether symbol $1 exists in header])
+       header=0
+       for file in $3; do
+               grep -q "$2" "$LINUX/$file" 2>/dev/null
+               rc=$?
+               if test $rc -eq 0; then
+                       header=1
+                       break;
+               fi
+       done
+       if test $header -eq 0; then
+               AC_MSG_RESULT([no])
+               $5
+       else
+               AC_MSG_RESULT([yes])
+               $4
+       fi
+])
+
 dnl #
 dnl # SPL_CHECK_HEADER
 dnl # check whether header exists and define HAVE_$2_HEADER
@@ -432,41 +730,55 @@ AC_DEFUN([SPL_CHECK_HEADER],
 ])
 
 dnl #
-dnl # 2.6.24 API change,
-dnl # check if uintptr_t typedef is defined
+dnl # Use the atomic implemenation based on global spinlocks.  This
+dnl # should only be needed by 32-bit kernels which do not provide
+dnl # the atomic64_* API.  It may be optionally enabled as a fallback
+dnl # if problems are observed with the direct mapping to the native
+dnl # Linux atomic operations.  You may not disable atomic spinlocks
+dnl # if you kernel does not an atomic64_* API.
 dnl #
-AC_DEFUN([SPL_AC_TYPE_UINTPTR_T],
-       [AC_MSG_CHECKING([whether kernel defines uintptr_t])
-       SPL_LINUX_TRY_COMPILE([
-               #include <linux/types.h>
-       ],[
-               uintptr_t *ptr;
-       ],[
-               AC_MSG_RESULT([yes])
-               AC_DEFINE(HAVE_UINTPTR_T, 1,
-                         [kernel defines uintptr_t])
-       ],[
-               AC_MSG_RESULT([no])
-       ])
-])
+AC_DEFUN([SPL_AC_ATOMIC_SPINLOCK], [
+       AC_ARG_ENABLE([atomic-spinlocks],
+               [AS_HELP_STRING([--enable-atomic-spinlocks],
+               [Atomic types use spinlocks @<:@default=check@:>@])],
+               [],
+               [enable_atomic_spinlocks=check])
 
-dnl #
-dnl # 2.6.x API change,
-dnl # check if atomic64_t typedef is defined
-dnl #
-AC_DEFUN([SPL_AC_TYPE_ATOMIC64_T],
-       [AC_MSG_CHECKING([whether kernel defines atomic64_t])
        SPL_LINUX_TRY_COMPILE([
                #include <asm/atomic.h>
        ],[
-               atomic64_t *ptr;
+               atomic64_t *ptr __attribute__ ((unused));
        ],[
-               AC_MSG_RESULT([yes])
+               have_atomic64_t=yes
                AC_DEFINE(HAVE_ATOMIC64_T, 1,
-                         [kernel defines atomic64_t])
+                       [kernel defines atomic64_t])
        ],[
-               AC_MSG_RESULT([no])
+               have_atomic64_t=no
+       ])
+
+       AS_IF([test "x$enable_atomic_spinlocks" = xcheck], [
+               AS_IF([test "x$have_atomic64_t" = xyes], [
+                       enable_atomic_spinlocks=no
+               ],[
+                       enable_atomic_spinlocks=yes
+               ])
+       ])
+
+       AS_IF([test "x$enable_atomic_spinlocks" = xyes], [
+               AC_DEFINE([ATOMIC_SPINLOCK], [1],
+                       [Atomic types use spinlocks])
+       ],[
+               AS_IF([test "x$have_atomic64_t" = xno], [
+                       AC_MSG_FAILURE(
+                       [--disable-atomic-spinlocks given but required atomic64 support is unavailable])
+               ])
        ])
+
+       AC_MSG_CHECKING([whether atomic types use spinlocks])
+       AC_MSG_RESULT([$enable_atomic_spinlocks])
+
+       AC_MSG_CHECKING([whether kernel defines atomic64_t])
+       AC_MSG_RESULT([$have_atomic64_t])
 ])
 
 dnl #
@@ -477,6 +789,7 @@ AC_DEFUN([SPL_AC_TYPE_ATOMIC64_CMPXCHG],
        [AC_MSG_CHECKING([whether kernel defines atomic64_cmpxchg])
        SPL_LINUX_TRY_COMPILE([
                #include <asm/atomic.h>
+               #include <asm/system.h>
        ],[
                atomic64_cmpxchg((atomic64_t *)NULL, 0, 0);
        ],[
@@ -507,6 +820,25 @@ AC_DEFUN([SPL_AC_TYPE_ATOMIC64_XCHG],
        ])
 ])
 
+dnl #
+dnl # 2.6.24 API change,
+dnl # check if uintptr_t typedef is defined
+dnl #
+AC_DEFUN([SPL_AC_TYPE_UINTPTR_T],
+       [AC_MSG_CHECKING([whether kernel defines uintptr_t])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/types.h>
+       ],[
+               uintptr_t *ptr __attribute__ ((unused));
+       ],[
+               AC_MSG_RESULT([yes])
+               AC_DEFINE(HAVE_UINTPTR_T, 1,
+                         [kernel defines uintptr_t])
+       ],[
+               AC_MSG_RESULT([no])
+       ])
+])
+
 dnl #
 dnl # 2.6.20 API change,
 dnl # INIT_WORK use 2 args and not store data inside
@@ -516,7 +848,7 @@ AC_DEFUN([SPL_AC_3ARGS_INIT_WORK],
        SPL_LINUX_TRY_COMPILE([
                #include <linux/workqueue.h>
        ],[
-               struct work_struct work;
+               struct work_struct work __attribute__ ((unused));
                INIT_WORK(&work, NULL, NULL);
        ],[
                AC_MSG_RESULT(yes)
@@ -536,7 +868,7 @@ AC_DEFUN([SPL_AC_2ARGS_REGISTER_SYSCTL],
        SPL_LINUX_TRY_COMPILE([
                #include <linux/sysctl.h>
        ],[
-               return register_sysctl_table(NULL,0);
+               (void) register_sysctl_table(NULL, 0);
        ],[
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_2ARGS_REGISTER_SYSCTL, 1,
@@ -565,6 +897,34 @@ AC_DEFUN([SPL_AC_SET_SHRINKER], [
        ])
 ])
 
+dnl #
+dnl # 2.6.35 API change,
+dnl # Add context to shrinker callback
+dnl #
+AC_DEFUN([SPL_AC_3ARGS_SHRINKER_CALLBACK],
+       [AC_MSG_CHECKING([whether shrinker callback wants 3 args])
+       tmp_flags="$EXTRA_KCFLAGS"
+       EXTRA_KCFLAGS="-Werror"
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/mm.h>
+
+               int shrinker_cb(struct shrinker *, int, unsigned int);
+       ],[
+               struct shrinker cache_shrinker = {
+                       .shrink = shrinker_cb,
+                       .seeks = DEFAULT_SEEKS,
+               };
+               register_shrinker(&cache_shrinker);
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_3ARGS_SHRINKER_CALLBACK, 1,
+                         [shrinker callback wants 3 args])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+       EXTRA_KCFLAGS="$tmp_flags"
+])
+
 dnl #
 dnl # 2.6.25 API change,
 dnl # struct path entry added to struct nameidata
@@ -574,7 +934,7 @@ AC_DEFUN([SPL_AC_PATH_IN_NAMEIDATA],
        SPL_LINUX_TRY_COMPILE([
                #include <linux/namei.h>
        ],[
-               struct nameidata nd;
+               struct nameidata nd __attribute__ ((unused));
 
                nd.path.mnt = NULL;
                nd.path.dentry = NULL;
@@ -617,6 +977,25 @@ AC_DEFUN([SPL_AC_CTL_UNNUMBERED],
        ])
 ])
 
+dnl #
+dnl # 2.6.33 API change,
+dnl # Removed .ctl_name from struct ctl_table.
+dnl #
+AC_DEFUN([SPL_AC_CTL_NAME], [
+       AC_MSG_CHECKING([whether struct ctl_table has ctl_name])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/sysctl.h>
+       ],[
+               struct ctl_table ctl __attribute__ ((unused));
+               ctl.ctl_name = 0;
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_CTL_NAME, 1, [struct ctl_table has ctl_name])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])
+
 dnl #
 dnl # 2.6.16 API change.
 dnl # Check if 'fls64()' is available
@@ -727,7 +1106,9 @@ AC_DEFUN([SPL_AC_TIMESPEC_SUB], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/time.h>
        ],[
-               struct timespec a, b, c = { 0 };
+               struct timespec a = { 0 };
+               struct timespec b = { 0 };
+               struct timespec c __attribute__ ((unused));
                c = timespec_sub(a, b);
        ],[
                AC_MSG_RESULT(yes)
@@ -746,7 +1127,8 @@ AC_DEFUN([SPL_AC_INIT_UTSNAME], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/utsname.h>
        ],[
-               struct new_utsname *a = init_utsname();
+               struct new_utsname *a __attribute__ ((unused));
+               a = init_utsname();
        ],[
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_INIT_UTSNAME, 1, [init_utsname() is available])
@@ -777,7 +1159,8 @@ AC_DEFUN([SPL_AC_FILES_FDTABLE], [
                #endif
        ],[
                struct files_struct *files = current->files;
-               struct fdtable *fdt = files_fdtable(files);
+               struct fdtable *fdt __attribute__ ((unused));
+               fdt = files_fdtable(files);
        ],[
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_FILES_FDTABLE, 1, [files_fdtable() is available])
@@ -803,7 +1186,8 @@ AC_DEFUN([SPL_AC_KMALLOC_NODE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/slab.h>
        ],[
-               void *a = kmalloc_node(1, GFP_KERNEL, 0);
+               void *a __attribute__ ((unused));
+               a = kmalloc_node(1, GFP_KERNEL, 0);
        ],[
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_KMALLOC_NODE, 1, [kmalloc_node() is available])
@@ -855,7 +1239,7 @@ AC_DEFUN([SPL_AC_MUTEX_OWNER], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mutex.h>
        ],[
-               struct mutex mtx;
+               struct mutex mtx __attribute__ ((unused));
                mtx.owner = NULL;
        ],[
                AC_MSG_RESULT(yes)
@@ -865,6 +1249,32 @@ AC_DEFUN([SPL_AC_MUTEX_OWNER], [
        ])
 ])
 
+dnl #
+dnl # 2.6.39 API change,
+dnl # Owner type change.  A Linux mutex prior to 2.6.39 would store
+dnl # the owner as a thread_info pointer when CONFIG_DEBUG_MUTEXES
+dnl # was defined.  As of 2.6.39 this was changed to a task_struct
+dnl # pointer which frankly makes a lot more sense.
+dnl #
+AC_DEFUN([SPL_AC_MUTEX_OWNER_TASK_STRUCT], [
+       AC_MSG_CHECKING([whether struct mutex owner is a task_struct])
+       tmp_flags="$EXTRA_KCFLAGS"
+       EXTRA_KCFLAGS="-Werror"
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/mutex.h>
+       ],[
+               struct mutex mtx __attribute__ ((unused));
+               mtx.owner = current;
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_MUTEX_OWNER_TASK_STRUCT, 1,
+               [struct mutex owner is a task_struct])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+       EXTRA_KCFLAGS="$tmp_flags"
+])
+
 dnl #
 dnl # 2.6.18 API change,
 dnl # First introduced 'mutex_lock_nested()' in include/linux/mutex.h,
@@ -888,32 +1298,6 @@ AC_DEFUN([SPL_AC_MUTEX_LOCK_NESTED], [
        ])
 ])
 
-dnl #
-dnl # 2.6.22 API change,
-dnl # First introduced 'div64_64()' in lib/div64.c
-dnl 
-AC_DEFUN([SPL_AC_DIV64_64], [
-       SPL_CHECK_SYMBOL_EXPORT(
-               [div64_64],
-               [],
-               [AC_DEFINE(HAVE_DIV64_64, 1,
-               [div64_64() is available])],
-               [])
-])
-
-dnl #
-dnl # 2.6.26 API change,
-dnl # Renamed 'div64_64()' to 'div64_u64' in lib/div64.c
-dnl #
-AC_DEFUN([SPL_AC_DIV64_U64], [
-       SPL_CHECK_SYMBOL_EXPORT(
-               [div64_u64],
-               [],
-               [AC_DEFINE(HAVE_DIV64_U64, 1,
-               [div64_u64() is available])],
-               [])
-])
-
 dnl #
 dnl # 2.6.27 API change,
 dnl # on_each_cpu() uses 3 args, no 'retry' argument
@@ -1057,7 +1441,7 @@ AC_DEFUN([SPL_AC_GLOBAL_PAGE_STATE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               unsigned long state;
+               unsigned long state __attribute__ ((unused));
                state = global_page_state(0);
        ],[
                AC_MSG_RESULT(yes)
@@ -1083,7 +1467,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_FREE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               enum zone_stat_item zsi;
+               enum zone_stat_item zsi __attribute__ ((unused));
                zsi = NR_FREE_PAGES;
        ],[
                AC_MSG_RESULT(yes)
@@ -1110,7 +1494,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_INACTIVE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               enum zone_stat_item zsi;
+               enum zone_stat_item zsi __attribute__ ((unused));
                zsi = NR_INACTIVE;
        ],[
                AC_MSG_RESULT(yes)
@@ -1124,7 +1508,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_INACTIVE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               enum zone_stat_item zsi;
+               enum zone_stat_item zsi __attribute__ ((unused));
                zsi = NR_INACTIVE_ANON;
        ],[
                AC_MSG_RESULT(yes)
@@ -1138,7 +1522,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_INACTIVE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               enum zone_stat_item zsi;
+               enum zone_stat_item zsi __attribute__ ((unused));
                zsi = NR_INACTIVE_FILE;
        ],[
                AC_MSG_RESULT(yes)
@@ -1165,7 +1549,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_ACTIVE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               enum zone_stat_item zsi;
+               enum zone_stat_item zsi __attribute__ ((unused));
                zsi = NR_ACTIVE;
        ],[
                AC_MSG_RESULT(yes)
@@ -1179,7 +1563,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_ACTIVE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               enum zone_stat_item zsi;
+               enum zone_stat_item zsi __attribute__ ((unused));
                zsi = NR_ACTIVE_ANON;
        ],[
                AC_MSG_RESULT(yes)
@@ -1193,7 +1577,7 @@ AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_ACTIVE], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/mm.h>
        ],[
-               enum zone_stat_item zsi;
+               enum zone_stat_item zsi __attribute__ ((unused));
                zsi = NR_ACTIVE_FILE;
        ],[
                AC_MSG_RESULT(yes)
@@ -1246,6 +1630,19 @@ AC_DEFUN([SPL_AC_GET_ZONE_COUNTS], [
        ])
 ])
 
+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])],
+               [])
+])
+
 dnl #
 dnl # Symbol available in RHEL kernels not in stock kernels.
 dnl #
@@ -1316,6 +1713,31 @@ AC_DEFUN([SPL_AC_4ARGS_VFS_RENAME],
        ])
 ])
 
+dnl #
+dnl # 2.6.36 API change,
+dnl # The 'struct fs_struct->lock' was changed from a rwlock_t to
+dnl # a spinlock_t to improve the fastpath performance.
+dnl #
+AC_DEFUN([SPL_AC_FS_STRUCT_SPINLOCK], [
+       AC_MSG_CHECKING([whether struct fs_struct uses spinlock_t])
+       tmp_flags="$EXTRA_KCFLAGS"
+       EXTRA_KCFLAGS="-Werror"
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/sched.h>
+               #include <linux/fs_struct.h>
+       ],[
+               struct fs_struct fs;
+               spin_lock_init(&fs.lock);
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_FS_STRUCT_SPINLOCK, 1,
+                         [struct fs_struct uses spinlock_t])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+       EXTRA_KCFLAGS="$tmp_flags"
+])
+
 dnl #
 dnl # 2.6.29 API change,
 dnl # check whether 'struct cred' exists
@@ -1325,7 +1747,7 @@ AC_DEFUN([SPL_AC_CRED_STRUCT], [
        SPL_LINUX_TRY_COMPILE([
                #include <linux/cred.h>
        ],[
-               struct cred *cr;
+               struct cred *cr __attribute__ ((unused));
                cr  = NULL;
        ],[
                AC_MSG_RESULT(yes)
@@ -1359,3 +1781,271 @@ AC_DEFUN([SPL_AC_PUT_TASK_STRUCT], [
                [__put_task_struct() is available])],
                [])
 ])
+
+dnl #
+dnl # 2.6.32 API change,
+dnl # Unused 'struct file *' removed from prototype.
+dnl #
+AC_DEFUN([SPL_AC_5ARGS_PROC_HANDLER], [
+       AC_MSG_CHECKING([whether proc_handler() wants 5 args])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/sysctl.h>
+       ],[
+               proc_dostring(NULL, 0, NULL, NULL, NULL);
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_5ARGS_PROC_HANDLER, 1,
+                         [proc_handler() wants 5 args])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])
+
+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])],
+               [])
+])
+
+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])],
+               [])
+])
+
+dnl #
+dnl # 2.6.35 API change,
+dnl # Unused 'struct dentry *' removed from vfs_fsync() prototype.
+dnl #
+AC_DEFUN([SPL_AC_2ARGS_VFS_FSYNC], [
+       AC_MSG_CHECKING([whether vfs_fsync() wants 2 args])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/fs.h>
+       ],[
+               vfs_fsync(NULL, 0);
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_2ARGS_VFS_FSYNC, 1, [vfs_fsync() wants 2 args])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])
+
+dnl #
+dnl # 2.6.33 API change. Also backported in RHEL5 as of 2.6.18-190.el5.
+dnl # Earlier versions of rwsem_is_locked() were inline and had a race
+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])],
+               [])
+])
+
+dnl #
+dnl # 2.6.37 API compat,
+dnl # The function invalidate_inodes() is no longer exported by the kernel.
+dnl # The prototype however is still available which means it is safe
+dnl # to acquire the symbol's address using spl_kallsyms_lookup_name().
+dnl #
+dnl # The Proxmox VE kernel contains a patch which renames the function
+dnl # invalidate_inodes() to invalidate_inodes_check().  In the process
+dnl # it adds a 'check' argument and a '#define invalidate_inodes(x)'
+dnl # compatibility wrapper for legacy callers.  Therefore, if either
+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])],
+               [])
+])
+
+dnl #
+dnl # 2.6.39 API compat,
+dnl # The function invalidate_inodes() now take 2 arguments.  The second
+dnl # 'kill_dirty' argument describes how invalidate_inodes() should
+dnl # handle dirty inodes.  Only when set will dirty inodes be discarded,
+dnl # otherwise they will be handled as busy.
+dnl #
+dnl # Unfortunately, we don't have access to the invalidate_inodes()
+dnl # prototype so it's not easy to check how many arguments it takes.
+dnl # However, this change was done for the benefit of invalidate_device()
+dnl # which also added an argument.  The invalidate_device() symbol does
+dnl # exist in the development headers so if it takes two arguments we
+dnl # can fairly safely infer that invalidate_inodes() takes two arguments
+dnl # as well.  See commit 93b270f76e7ef3b81001576860c2701931cdc78b.
+dnl #
+AC_DEFUN([SPL_AC_KERNEL_2ARGS_INVALIDATE_INODES],
+       [AC_MSG_CHECKING([whether invalidate_inodes() wants 2 args])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/fs.h>
+       ],[
+               return __invalidate_device(NULL, 0);
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_2ARGS_INVALIDATE_INODES, 1,
+                         [invalidate_inodes() wants 2 args])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])
+
+dnl #
+dnl # 2.6.xx API compat,
+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])],
+               [])
+])
+
+dnl #
+dnl # 2.6.xx API compat,
+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])],
+               [])
+])
+
+dnl #
+dnl # 2.6.39 API compat,
+dnl # The path_lookup() function has been renamed to kern_path_parent()
+dnl # and the flags argument has been removed.  The only behavior now
+dnl # offered is that of LOOKUP_PARENT.  The spl already always passed
+dnl # this flag so dropping the flag does not impact us.
+dnl #
+AC_DEFUN([SPL_AC_KERN_PATH_PARENT_HEADER], [
+       SPL_CHECK_SYMBOL_HEADER(
+               [kern_path_parent],
+               [int kern_path_parent(const char \*, struct nameidata \*)],
+               [include/linux/namei.h],
+               [AC_DEFINE(HAVE_KERN_PATH_PARENT_HEADER, 1,
+               [kern_path_parent() is available])],
+               [])
+])
+
+dnl #
+dnl # 3.1 API compat,
+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])],
+               [])
+])
+
+dnl #
+dnl # 2.6.39 API compat,
+dnl # The function zlib_deflate_workspacesize() now take 2 arguments.
+dnl # This was done to avoid always having to allocate the maximum size
+dnl # workspace (268K).  The caller can now specific the windowBits and
+dnl # memLevel compression parameters to get a smaller workspace.
+dnl #
+AC_DEFUN([SPL_AC_2ARGS_ZLIB_DEFLATE_WORKSPACESIZE],
+       [AC_MSG_CHECKING([whether zlib_deflate_workspacesize() wants 2 args])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/zlib.h>
+       ],[
+               return zlib_deflate_workspacesize(MAX_WBITS, MAX_MEM_LEVEL);
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_2ARGS_ZLIB_DEFLATE_WORKSPACESIZE, 1,
+                         [zlib_deflate_workspacesize() wants 2 args])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])
+
+dnl #
+dnl # 2.6.39 API change,
+dnl # Shrinker adjust to use common shrink_control structure.
+dnl #
+AC_DEFUN([SPL_AC_SHRINK_CONTROL_STRUCT], [
+       AC_MSG_CHECKING([whether struct shrink_control exists])
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/mm.h>
+       ],[
+               struct shrink_control sc __attribute__ ((unused));
+
+               sc.nr_to_scan = 0;
+               sc.gfp_mask = GFP_KERNEL;
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_SHRINK_CONTROL_STRUCT, 1,
+                       [struct shrink_control exists])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])
+
+dnl #
+dnl # 3.1 API Change
+dnl #
+dnl # The rw_semaphore.wait_lock member was changed from spinlock_t to
+dnl # raw_spinlock_t at commit ddb6c9b58a19edcfac93ac670b066c836ff729f1.
+dnl #
+AC_DEFUN([SPL_AC_RWSEM_SPINLOCK_IS_RAW], [
+       AC_MSG_CHECKING([whether struct rw_semaphore member wait_lock is raw])
+       tmp_flags="$EXTRA_KCFLAGS"
+       EXTRA_KCFLAGS="-Werror"
+       SPL_LINUX_TRY_COMPILE([
+               #include <linux/rwsem.h>
+       ],[
+               struct rw_semaphore dummy_semaphore __attribute__ ((unused));
+               raw_spinlock_t dummy_lock __attribute__ ((unused));
+               dummy_semaphore.wait_lock = dummy_lock;
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(RWSEM_SPINLOCK_IS_RAW, 1,
+               [struct rw_semaphore member wait_lock is raw_spinlock_t])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+       EXTRA_KCFLAGS="$tmp_flags"
+])