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 <[email protected]>
Closes #9566 

1 files changed, 1 insertions, 38 deletions

diff --git a/config/kernel-security-inode-init.m4 b/config/kernel-security-inode-init.m4
index 0dea7e392..4e4bfd29b 100644
--- a/config/kernel-security-inode-init.m4
+++ b/config/kernel-security-inode-init.m4
@@ -1,37 +1,4 @@
 dnl #
-dnl # 2.6.39 API change
-dnl # The security_inode_init_security() function now takes an additional
-dnl # qstr argument which must be passed in from the dentry if available.
-dnl # Passing a NULL is safe when no qstr is available the relevant
-dnl # security checks will just be skipped.
-dnl #
-AC_DEFUN([ZFS_AC_KERNEL_SRC_SECURITY_INODE_INIT_SECURITY_6ARGS], [
-	ZFS_LINUX_TEST_SRC([security_inode_init_security_6args], [
-		#include <linux/security.h>
-	],[
-		struct inode *ip __attribute__ ((unused)) = NULL;
-		struct inode *dip __attribute__ ((unused)) = NULL;
-		const struct qstr *str __attribute__ ((unused)) = NULL;
-		char *name __attribute__ ((unused)) = NULL;
-		void *value __attribute__ ((unused)) = NULL;
-		size_t len __attribute__ ((unused)) = 0;
-
-		security_inode_init_security(ip, dip, str, &name, &value, &len);
-	])
-])
-
-AC_DEFUN([ZFS_AC_KERNEL_SECURITY_INODE_INIT_SECURITY_6ARGS], [
-	AC_MSG_CHECKING([whether security_inode_init_security wants 6 args])
-	ZFS_LINUX_TEST_RESULT([security_inode_init_security_6args], [
-		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_6ARGS_SECURITY_INODE_INIT_SECURITY, 1,
-		    [security_inode_init_security wants 6 args])
-	],[
-		AC_MSG_RESULT(no)
-	])
-])
-
-dnl #
 dnl # 3.2 API change
 dnl # The security_inode_init_security() API has been changed to include
 dnl # a filesystem specific callback to write security extended attributes.
@@ -55,19 +22,15 @@ AC_DEFUN([ZFS_AC_KERNEL_SECURITY_INODE_INIT_SECURITY_CALLBACK], [
 	AC_MSG_CHECKING([whether security_inode_init_security wants callback])
 	ZFS_LINUX_TEST_RESULT([security_inode_init_security], [
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_CALLBACK_SECURITY_INODE_INIT_SECURITY, 1,
-		    [security_inode_init_security wants callback])
 	],[
-		AC_MSG_RESULT(no)
+		ZFS_LINUX_TEST_ERROR([security_inode_init_security callback])
 	])
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_SRC_SECURITY_INODE], [
-	ZFS_AC_KERNEL_SRC_SECURITY_INODE_INIT_SECURITY_6ARGS
 	ZFS_AC_KERNEL_SRC_SECURITY_INODE_INIT_SECURITY_CALLBACK
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_SECURITY_INODE], [
-	ZFS_AC_KERNEL_SECURITY_INODE_INIT_SECURITY_6ARGS
 	ZFS_AC_KERNEL_SECURITY_INODE_INIT_SECURITY_CALLBACK
 ])