freebsd-nq/config/kernel-rwsem.m4
Brian Behlendorf 066e825221
Linux compat: Minimum kernel version 3.10
Increase the minimum supported kernel version from 2.6.32 to 3.10.
This removes support for the following Linux enterprise distributions.

    Distribution     | Kernel | End of Life
    ---------------- | ------ | -------------
    Ubuntu 12.04 LTS | 3.2    | Apr 28, 2017
    SLES 11          | 3.0    | Mar 32, 2019
    RHEL / CentOS 6  | 2.6.32 | Nov 30, 2020

The following changes were made as part of removing support.

* Updated `configure` to enforce a minimum kernel version as
  specified in the META file (Linux-Minimum: 3.10).

    configure: error:
        *** Cannot build against kernel version 2.6.32.
        *** The minimum supported kernel version is 3.10.

* Removed all `configure` kABI checks and matching C code for
  interfaces which solely predate the Linux 3.10 kernel.

* Updated all `configure` kABI checks to fail when an interface is
  missing which was in the 3.10 kernel up to the latest 5.1 kernel.
  Removed the HAVE_* preprocessor defines for these checks and
  updated the code to unconditionally use the verified interface.

* Inverted the detection logic in several kABI checks to match
  the new interface as it appears in 3.10 and newer and not the
  legacy interface.

* Consolidated the following checks in to individual files. Due
  the large number of changes in the checks it made sense to handle
  this now.  It would be desirable to group other related checks in
  the same fashion, but this as left as future work.

  - config/kernel-blkdev.m4 - Block device kABI checks
  - config/kernel-blk-queue.m4 - Block queue kABI checks
  - config/kernel-bio.m4 - Bio interface kABI checks

* Removed the kABI checks for sops->nr_cached_objects() and
  sops->free_cached_objects().  These interfaces are currently unused.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #9566
2019-11-12 08:59:06 -08:00

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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([ZFS_AC_KERNEL_SRC_RWSEM_SPINLOCK_IS_RAW], [
ZFS_LINUX_TEST_SRC([rwsem_spinlock_is_raw], [
#include <linux/rwsem.h>
],[
struct rw_semaphore dummy_semaphore __attribute__ ((unused));
raw_spinlock_t dummy_lock __attribute__ ((unused)) =
__RAW_SPIN_LOCK_INITIALIZER(dummy_lock);
dummy_semaphore.wait_lock = dummy_lock;
])
])
AC_DEFUN([ZFS_AC_KERNEL_RWSEM_SPINLOCK_IS_RAW], [
AC_MSG_CHECKING([whether struct rw_semaphore member wait_lock is raw])
ZFS_LINUX_TEST_RESULT([rwsem_spinlock_is_raw], [
AC_MSG_RESULT(yes)
],[
ZFS_LINUX_TEST_ERROR([rwsem_spinlock_is_raw])
])
])
dnl #
dnl # 3.16 API Change
dnl #
dnl # rwsem-spinlock "->activity" changed to "->count"
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_RWSEM_ACTIVITY], [
ZFS_LINUX_TEST_SRC([rwsem_activity], [
#include <linux/rwsem.h>
],[
struct rw_semaphore dummy_semaphore __attribute__ ((unused));
dummy_semaphore.activity = 0;
])
])
AC_DEFUN([ZFS_AC_KERNEL_RWSEM_ACTIVITY], [
AC_MSG_CHECKING([whether struct rw_semaphore has member activity])
ZFS_LINUX_TEST_RESULT([rwsem_activity], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_RWSEM_ACTIVITY, 1,
[struct rw_semaphore has member activity])
],[
AC_MSG_RESULT(no)
])
])
dnl #
dnl # 4.8 API Change
dnl #
dnl # rwsem "->count" changed to atomic_long_t type
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_RWSEM_ATOMIC_LONG_COUNT], [
ZFS_LINUX_TEST_SRC([rwsem_atomic_long_count], [
#include <linux/rwsem.h>
],[
DECLARE_RWSEM(dummy_semaphore);
(void) atomic_long_read(&dummy_semaphore.count);
])
])
AC_DEFUN([ZFS_AC_KERNEL_RWSEM_ATOMIC_LONG_COUNT], [
AC_MSG_CHECKING(
[whether struct rw_semaphore has atomic_long_t member count])
ZFS_LINUX_TEST_RESULT([rwsem_atomic_long_count], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_RWSEM_ATOMIC_LONG_COUNT, 1,
[struct rw_semaphore has atomic_long_t member count])
],[
AC_MSG_RESULT(no)
])
])
AC_DEFUN([ZFS_AC_KERNEL_SRC_RWSEM], [
ZFS_AC_KERNEL_SRC_RWSEM_SPINLOCK_IS_RAW
ZFS_AC_KERNEL_SRC_RWSEM_ACTIVITY
ZFS_AC_KERNEL_SRC_RWSEM_ATOMIC_LONG_COUNT
])
AC_DEFUN([ZFS_AC_KERNEL_RWSEM], [
ZFS_AC_KERNEL_RWSEM_SPINLOCK_IS_RAW
ZFS_AC_KERNEL_RWSEM_ACTIVITY
ZFS_AC_KERNEL_RWSEM_ATOMIC_LONG_COUNT
])