v4.19.13 snapshot.
diff --git a/fs/compat.c b/fs/compat.c
new file mode 100644
index 0000000..4a0aaaf
--- /dev/null
+++ b/fs/compat.c
@@ -0,0 +1,135 @@
+/*
+ * linux/fs/compat.c
+ *
+ * Kernel compatibililty routines for e.g. 32 bit syscall support
+ * on 64 bit kernels.
+ *
+ * Copyright (C) 2002 Stephen Rothwell, IBM Corporation
+ * Copyright (C) 1997-2000 Jakub Jelinek (jakub@redhat.com)
+ * Copyright (C) 1998 Eddie C. Dost (ecd@skynet.be)
+ * Copyright (C) 2001,2002 Andi Kleen, SuSE Labs
+ * Copyright (C) 2003 Pavel Machek (pavel@ucw.cz)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/compat.h>
+#include <linux/nfs4_mount.h>
+#include <linux/syscalls.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include "internal.h"
+
+struct compat_nfs_string {
+ compat_uint_t len;
+ compat_uptr_t data;
+};
+
+static inline void compat_nfs_string(struct nfs_string *dst,
+ struct compat_nfs_string *src)
+{
+ dst->data = compat_ptr(src->data);
+ dst->len = src->len;
+}
+
+struct compat_nfs4_mount_data_v1 {
+ compat_int_t version;
+ compat_int_t flags;
+ compat_int_t rsize;
+ compat_int_t wsize;
+ compat_int_t timeo;
+ compat_int_t retrans;
+ compat_int_t acregmin;
+ compat_int_t acregmax;
+ compat_int_t acdirmin;
+ compat_int_t acdirmax;
+ struct compat_nfs_string client_addr;
+ struct compat_nfs_string mnt_path;
+ struct compat_nfs_string hostname;
+ compat_uint_t host_addrlen;
+ compat_uptr_t host_addr;
+ compat_int_t proto;
+ compat_int_t auth_flavourlen;
+ compat_uptr_t auth_flavours;
+};
+
+static int do_nfs4_super_data_conv(void *raw_data)
+{
+ int version = *(compat_uint_t *) raw_data;
+
+ if (version == 1) {
+ struct compat_nfs4_mount_data_v1 *raw = raw_data;
+ struct nfs4_mount_data *real = raw_data;
+
+ /* copy the fields backwards */
+ real->auth_flavours = compat_ptr(raw->auth_flavours);
+ real->auth_flavourlen = raw->auth_flavourlen;
+ real->proto = raw->proto;
+ real->host_addr = compat_ptr(raw->host_addr);
+ real->host_addrlen = raw->host_addrlen;
+ compat_nfs_string(&real->hostname, &raw->hostname);
+ compat_nfs_string(&real->mnt_path, &raw->mnt_path);
+ compat_nfs_string(&real->client_addr, &raw->client_addr);
+ real->acdirmax = raw->acdirmax;
+ real->acdirmin = raw->acdirmin;
+ real->acregmax = raw->acregmax;
+ real->acregmin = raw->acregmin;
+ real->retrans = raw->retrans;
+ real->timeo = raw->timeo;
+ real->wsize = raw->wsize;
+ real->rsize = raw->rsize;
+ real->flags = raw->flags;
+ real->version = raw->version;
+ }
+
+ return 0;
+}
+
+#define NFS4_NAME "nfs4"
+
+COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
+ const char __user *, dir_name,
+ const char __user *, type, compat_ulong_t, flags,
+ const void __user *, data)
+{
+ char *kernel_type;
+ void *options;
+ char *kernel_dev;
+ int retval;
+
+ kernel_type = copy_mount_string(type);
+ retval = PTR_ERR(kernel_type);
+ if (IS_ERR(kernel_type))
+ goto out;
+
+ kernel_dev = copy_mount_string(dev_name);
+ retval = PTR_ERR(kernel_dev);
+ if (IS_ERR(kernel_dev))
+ goto out1;
+
+ options = copy_mount_options(data);
+ retval = PTR_ERR(options);
+ if (IS_ERR(options))
+ goto out2;
+
+ if (kernel_type && options) {
+ if (!strcmp(kernel_type, NFS4_NAME)) {
+ retval = -EINVAL;
+ if (do_nfs4_super_data_conv(options))
+ goto out3;
+ }
+ }
+
+ retval = do_mount(kernel_dev, dir_name, kernel_type, flags, options);
+
+ out3:
+ kfree(options);
+ out2:
+ kfree(kernel_dev);
+ out1:
+ kfree(kernel_type);
+ out:
+ return retval;
+}