diff --git a/config/kernel-acl.m4 b/config/kernel-acl.m4
index e53b546af..090381858 100644
--- a/config/kernel-acl.m4
+++ b/config/kernel-acl.m4
@@ -21,34 +21,6 @@ AC_DEFUN([ZFS_AC_KERNEL_POSIX_ACL_EQUIV_MODE_WANTS_UMODE_T], [
 	])
 ])
 
-dnl #
-dnl # 4.8 API change,
-dnl # The function posix_acl_valid now must be passed a namespace.
-dnl #
-AC_DEFUN([ZFS_AC_KERNEL_SRC_POSIX_ACL_VALID_WITH_NS], [
-	ZFS_LINUX_TEST_SRC([posix_acl_valid_with_ns], [
-		#include <linux/fs.h>
-		#include <linux/posix_acl.h>
-	],[
-		struct user_namespace *user_ns = NULL;
-		const struct posix_acl *acl = NULL;
-		int error;
-
-		error = posix_acl_valid(user_ns, acl);
-	])
-])
-
-AC_DEFUN([ZFS_AC_KERNEL_POSIX_ACL_VALID_WITH_NS], [
-	AC_MSG_CHECKING([whether posix_acl_valid() wants user namespace])
-	ZFS_LINUX_TEST_RESULT([posix_acl_valid_with_ns], [
-		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_POSIX_ACL_VALID_WITH_NS, 1,
-		    [posix_acl_valid() wants user namespace])
-	],[
-		AC_MSG_RESULT(no)
-	])
-])
-
 dnl #
 dnl # 3.1 API change,
 dnl # Check if inode_operations contains the function get_acl
@@ -226,7 +198,6 @@ AC_DEFUN([ZFS_AC_KERNEL_ACL_HAS_REFCOUNT], [
 
 AC_DEFUN([ZFS_AC_KERNEL_SRC_ACL], [
 	ZFS_AC_KERNEL_SRC_POSIX_ACL_EQUIV_MODE_WANTS_UMODE_T
-	ZFS_AC_KERNEL_SRC_POSIX_ACL_VALID_WITH_NS
 	ZFS_AC_KERNEL_SRC_INODE_OPERATIONS_GET_ACL
 	ZFS_AC_KERNEL_SRC_INODE_OPERATIONS_SET_ACL
 	ZFS_AC_KERNEL_SRC_ACL_HAS_REFCOUNT
@@ -234,7 +205,6 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_ACL], [
 
 AC_DEFUN([ZFS_AC_KERNEL_ACL], [
 	ZFS_AC_KERNEL_POSIX_ACL_EQUIV_MODE_WANTS_UMODE_T
-	ZFS_AC_KERNEL_POSIX_ACL_VALID_WITH_NS
 	ZFS_AC_KERNEL_INODE_OPERATIONS_GET_ACL
 	ZFS_AC_KERNEL_INODE_OPERATIONS_SET_ACL
 	ZFS_AC_KERNEL_ACL_HAS_REFCOUNT
diff --git a/include/os/linux/kernel/linux/vfs_compat.h b/include/os/linux/kernel/linux/vfs_compat.h
index aa8f4cc97..affd6caa0 100644
--- a/include/os/linux/kernel/linux/vfs_compat.h
+++ b/include/os/linux/kernel/linux/vfs_compat.h
@@ -161,18 +161,6 @@ zpl_posix_acl_release(struct posix_acl *acl)
 		zpl_posix_acl_release_impl(acl);
 #endif
 }
-
-/*
- * 4.8 API change,
- * posix_acl_valid() now must be passed a namespace, the namespace from
- * from super block associated with the given inode is used for this purpose.
- */
-#ifdef HAVE_POSIX_ACL_VALID_WITH_NS
-#define	zpl_posix_acl_valid(ip, acl)  posix_acl_valid(ip->i_sb->s_user_ns, acl)
-#else
-#define	zpl_posix_acl_valid(ip, acl)  posix_acl_valid(acl)
-#endif
-
 #endif /* CONFIG_FS_POSIX_ACL */
 
 static inline uid_t zfs_uid_read_impl(struct inode *ip)
diff --git a/module/os/linux/zfs/zpl_xattr.c b/module/os/linux/zfs/zpl_xattr.c
index f272054e0..dc0113d38 100644
--- a/module/os/linux/zfs/zpl_xattr.c
+++ b/module/os/linux/zfs/zpl_xattr.c
@@ -1329,7 +1329,7 @@ __zpl_xattr_acl_set_access(zidmap_t *mnt_ns,
 		if (IS_ERR(acl))
 			return (PTR_ERR(acl));
 		else if (acl) {
-			error = zpl_posix_acl_valid(ip, acl);
+			error = posix_acl_valid(ip->i_sb->s_user_ns, acl);
 			if (error) {
 				zpl_posix_acl_release(acl);
 				return (error);
@@ -1375,7 +1375,7 @@ __zpl_xattr_acl_set_default(zidmap_t *mnt_ns,
 		if (IS_ERR(acl))
 			return (PTR_ERR(acl));
 		else if (acl) {
-			error = zpl_posix_acl_valid(ip, acl);
+			error = posix_acl_valid(ip->i_sb->s_user_ns, acl);
 			if (error) {
 				zpl_posix_acl_release(acl);
 				return (error);