Eliminate runtime function pointer mods in autotools checks

[zfs.git] / config / kernel-shrink.m4

diff --git a/config/kernel-shrink.m4 b/config/kernel-shrink.m4
index ea748c9..479fb3a 100644 (file)
--- a/config/kernel-shrink.m4
+++ b/config/kernel-shrink.m4
@@ -8,15 +8,18 @@ AC_DEFUN([ZFS_AC_KERNEL_SHRINK], [
        AC_MSG_CHECKING([whether super_block has s_shrink])
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/fs.h>
-       ],[
-               int (*shrink)(struct shrinker *, struct shrink_control *sc)
-                       __attribute__ ((unused)) = NULL;
-               struct super_block sb __attribute__ ((unused)) = {
+
+               int shrink(struct shrinker *s, struct shrink_control *sc)
+                   { return 0; }
+
+               static const struct super_block
+                   sb __attribute__ ((unused)) = {
                        .s_shrink.shrink = shrink,
                        .s_shrink.seeks = DEFAULT_SEEKS,
                        .s_shrink.batch = 0,
                };
        ],[
+       ],[
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_SHRINK, 1, [struct super_block has s_shrink])
 
@@ -29,13 +32,15 @@ AC_DEFUN([ZFS_AC_KERNEL_NR_CACHED_OBJECTS], [
        AC_MSG_CHECKING([whether sops->nr_cached_objects() exists])
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/fs.h>
-       ],[
-               int (*nr_cached_objects)(struct super_block *)
-                       __attribute__ ((unused)) = NULL;
-               struct super_operations sops __attribute__ ((unused)) = {
+
+               int nr_cached_objects(struct super_block *sb) { return 0; }
+
+               static const struct super_operations
+                   sops __attribute__ ((unused)) = {
                        .nr_cached_objects = nr_cached_objects,
                };
        ],[
+       ],[
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_NR_CACHED_OBJECTS, 1,
                        [sops->nr_cached_objects() exists])
@@ -48,13 +53,16 @@ AC_DEFUN([ZFS_AC_KERNEL_FREE_CACHED_OBJECTS], [
        AC_MSG_CHECKING([whether sops->free_cached_objects() exists])
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/fs.h>
-       ],[
-               void (*free_cached_objects)(struct super_block *, int)
-                       __attribute__ ((unused)) = NULL;
-               struct super_operations sops __attribute__ ((unused)) = {
+
+               void free_cached_objects(struct super_block *sb, int x)
+                   { return; }
+
+               static const struct super_operations
+                   sops __attribute__ ((unused)) = {
                        .free_cached_objects = free_cached_objects,
                };
        ],[
+       ],[
                AC_MSG_RESULT(yes)
                AC_DEFINE(HAVE_FREE_CACHED_OBJECTS, 1,
                        [sops->free_cached_objects() exists])