Remove spl_invalidate_inodes()

This functionality is no longer required by ZFS, see commit
openzfs/zfs@7b3e34b.
Since there are no other consumers, and because it adds
additional autoconf complexity which must be maintained
the spl_invalidate_inodes() function has been removed.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue openzfs/zfs#795

config/spl-build.m4

@@ -76,8 +76,6 @@ AC_DEFUN([SPL_AC_CONFIG_KERNEL], [
 	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_KERNEL_FALLOCATE
 	SPL_AC_SHRINK_DCACHE_MEMORY
 	SPL_AC_SHRINK_ICACHE_MEMORY
@@ -2036,78 +2034,6 @@ AC_DEFUN([SPL_AC_EXPORTED_RWSEM_IS_LOCKED],
 	])
 ])
 
-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], [
-	AC_MSG_CHECKING([whether invalidate_inodes() is available])
-	SPL_LINUX_TRY_COMPILE_SYMBOL([
-		#include <linux/fs.h>
-	], [
-		invalidate_inodes;
-	], [invalidate_inodes], [], [
-		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_INVALIDATE_INODES, 1,
-		          [invalidate_inodes() is available])
-	], [
-		AC_MSG_RESULT(no)
-	])
-
-	AC_MSG_CHECKING([whether invalidate_inodes_check() is available])
-	SPL_LINUX_TRY_COMPILE_SYMBOL([
-		#include <linux/fs.h>
-		#ifndef invalidate_inodes
-		#error invalidate_inodes is not a macro
-		#endif
-	], [ ], [invalidate_inodes_check], [], [
-		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_INVALIDATE_INODES_CHECK, 1,
-		          [invalidate_inodes_check() is available])
-	], [
-		AC_MSG_RESULT(no)
-	])
-])
-
-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.

include/linux/mm_compat.h

@@ -44,34 +44,6 @@
 #define high_wmark_pages(z)	(z->pages_high)
 #endif
 
-/*
- * 2.6.37 API compat,
- * The function invalidate_inodes() is no longer exported by the kernel.
- * The prototype however is still available which means it is safe
- * to acquire the symbol's address using spl_kallsyms_lookup_name().
- *
- * 2.6.39 API compat,
- * As for 2.6.39 invalidate_inodes() was updated to take a second
- * argument which controls how dirty inodes should be handled.
- */
-#if defined(HAVE_INVALIDATE_INODES) || defined(HAVE_INVALIDATE_INODES_CHECK)
-# ifdef HAVE_2ARGS_INVALIDATE_INODES
-#  define spl_invalidate_inodes(sb, kd)	invalidate_inodes(sb, kd)
-# else
-#  define spl_invalidate_inodes(sb, kd)	invalidate_inodes(sb)
-# endif /* HAVE_2ARGS_INVALIDATE_INODES */
-#else
-# ifdef HAVE_2ARGS_INVALIDATE_INODES
-typedef int (*invalidate_inodes_t)(struct super_block *sb, bool kd);
-extern invalidate_inodes_t invalidate_inodes_fn;
-#  define spl_invalidate_inodes(sb, kd)	invalidate_inodes_fn(sb, kd)
-# else
-typedef int (*invalidate_inodes_t)(struct super_block *sb);
-extern invalidate_inodes_t invalidate_inodes_fn;
-#  define spl_invalidate_inodes(sb, kd)	invalidate_inodes_fn(sb)
-# endif /* HAVE_2ARGS_INVALIDATE_INODES */
-#endif /* HAVE_INVALIDATE_INODES || HAVE_INVALIDATE_INODES_CHECK */
-
 #if !defined(HAVE_SHRINK_CONTROL_STRUCT)
 struct shrink_control {
 	gfp_t gfp_mask;

module/spl/spl-kmem.c

@@ -180,11 +180,6 @@ spl_global_page_state(spl_zone_stat_item_t item)
 #endif /* NEED_GET_ZONE_COUNTS */
 EXPORT_SYMBOL(spl_global_page_state);
 
-#if !defined(HAVE_INVALIDATE_INODES) && !defined(HAVE_INVALIDATE_INODES_CHECK)
-invalidate_inodes_t invalidate_inodes_fn = SYMBOL_POISON;
-EXPORT_SYMBOL(invalidate_inodes_fn);
-#endif /* !HAVE_INVALIDATE_INODES && !HAVE_INVALIDATE_INODES_CHECK */
-
 #ifndef HAVE_SHRINK_DCACHE_MEMORY
 shrink_dcache_memory_t shrink_dcache_memory_fn = SYMBOL_POISON;
 EXPORT_SYMBOL(shrink_dcache_memory_fn);
@@ -2376,15 +2371,6 @@ spl_kmem_init_kallsyms_lookup(void)
 	 */
 	spl_kmem_init_globals();
 
-#if !defined(HAVE_INVALIDATE_INODES) && !defined(HAVE_INVALIDATE_INODES_CHECK)
-	invalidate_inodes_fn = (invalidate_inodes_t)
-		spl_kallsyms_lookup_name("invalidate_inodes");
-	if (!invalidate_inodes_fn) {
-		printk(KERN_ERR "Error: Unknown symbol invalidate_inodes\n");
-		return -EFAULT;
-	}
-#endif /* !HAVE_INVALIDATE_INODES && !HAVE_INVALIDATE_INODES_CHECK */
-
 #ifndef HAVE_SHRINK_DCACHE_MEMORY
 	/* When shrink_dcache_memory_fn == NULL support is disabled */
 	shrink_dcache_memory_fn = (shrink_dcache_memory_t)