SUNRPC: Move simple_get_bytes and simple_get_netobj into private header

Remove duplicated helper functions to parse opaque XDR objects
and place inside new file net/sunrpc/auth_gss/auth_gss_internal.h.
In the new file carry the license and copyright from the source file
net/sunrpc/auth_gss/auth_gss.c.  Finally, update the comment inside
include/linux/sunrpc/xdr.h since lockd is not the only user of
struct xdr_netobj.

Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

include/linux/sunrpc/xdr.h

@@ -25,8 +25,7 @@ struct rpc_rqst;
 #define XDR_QUADLEN(l)		(((l) + 3) >> 2)
 
 /*
- * Generic opaque `network object.' At the kernel level, this type
- * is used only by lockd.
+ * Generic opaque `network object.'
  */
 #define XDR_MAX_NETOBJ		1024
 struct xdr_netobj {

net/sunrpc/auth_gss/auth_gss.c

@@ -29,6 +29,7 @@
 #include <linux/uaccess.h>
 #include <linux/hashtable.h>
 
+#include "auth_gss_internal.h"
 #include "../netns.h"
 
 #include <trace/events/rpcgss.h>
@@ -125,35 +126,6 @@ gss_cred_set_ctx(struct rpc_cred *cred, struct gss_cl_ctx *ctx)
 	clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
 }
 
-static const void *
-simple_get_bytes(const void *p, const void *end, void *res, size_t len)
-{
-	const void *q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	memcpy(res, p, len);
-	return q;
-}
-
-static inline const void *
-simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
-{
-	const void *q;
-	unsigned int len;
-
-	p = simple_get_bytes(p, end, &len, sizeof(len));
-	if (IS_ERR(p))
-		return p;
-	q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	dest->data = kmemdup(p, len, GFP_NOFS);
-	if (unlikely(dest->data == NULL))
-		return ERR_PTR(-ENOMEM);
-	dest->len = len;
-	return q;
-}
-
 static struct gss_cl_ctx *
 gss_cred_get_ctx(struct rpc_cred *cred)
 {

net/sunrpc/auth_gss/auth_gss_internal.h

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * linux/net/sunrpc/auth_gss/auth_gss_internal.h
+ *
+ * Internal definitions for RPCSEC_GSS client authentication
+ *
+ * Copyright (c) 2000 The Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ */
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/sunrpc/xdr.h>
+
+static inline const void *
+simple_get_bytes(const void *p, const void *end, void *res, size_t len)
+{
+	const void *q = (const void *)((const char *)p + len);
+	if (unlikely(q > end || q < p))
+		return ERR_PTR(-EFAULT);
+	memcpy(res, p, len);
+	return q;
+}
+
+static inline const void *
+simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
+{
+	const void *q;
+	unsigned int len;
+
+	p = simple_get_bytes(p, end, &len, sizeof(len));
+	if (IS_ERR(p))
+		return p;
+	q = (const void *)((const char *)p + len);
+	if (unlikely(q > end || q < p))
+		return ERR_PTR(-EFAULT);
+	dest->data = kmemdup(p, len, GFP_NOFS);
+	if (unlikely(dest->data == NULL))
+		return ERR_PTR(-ENOMEM);
+	dest->len = len;
+	return q;
+}

net/sunrpc/auth_gss/gss_krb5_mech.c

@@ -21,6 +21,8 @@
 #include <linux/sunrpc/xdr.h>
 #include <linux/sunrpc/gss_krb5_enctypes.h>
 
+#include "auth_gss_internal.h"
+
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 # define RPCDBG_FACILITY	RPCDBG_AUTH
 #endif
@@ -143,35 +145,6 @@ get_gss_krb5_enctype(int etype)
 	return NULL;
 }
 
-static const void *
-simple_get_bytes(const void *p, const void *end, void *res, int len)
-{
-	const void *q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	memcpy(res, p, len);
-	return q;
-}
-
-static const void *
-simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
-{
-	const void *q;
-	unsigned int len;
-
-	p = simple_get_bytes(p, end, &len, sizeof(len));
-	if (IS_ERR(p))
-		return p;
-	q = (const void *)((const char *)p + len);
-	if (unlikely(q > end || q < p))
-		return ERR_PTR(-EFAULT);
-	res->data = kmemdup(p, len, GFP_NOFS);
-	if (unlikely(res->data == NULL))
-		return ERR_PTR(-ENOMEM);
-	res->len = len;
-	return q;
-}
-
 static inline const void *
 get_key(const void *p, const void *end,
 	struct krb5_ctx *ctx, struct crypto_sync_skcipher **res)