1 files changed, 63 insertions, 0 deletions

diff --git a/crypto/scatterwalk.h b/crypto/scatterwalk.h
new file mode 100644
index 000000000000..02aa56c649b4
--- /dev/null
+++ b/crypto/scatterwalk.h
@@ -0,0 +1,63 @@
+/*
+ * Cryptographic API.
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2002 Adam J. Richter <adam@yggdrasil.com>
+ * Copyright (c) 2004 Jean-Luc Cooke <jlcooke@certainkey.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ */
+
+#ifndef _CRYPTO_SCATTERWALK_H
+#define _CRYPTO_SCATTERWALK_H
+#include <linux/mm.h>
+#include <asm/scatterlist.h>
+
+struct scatter_walk {
+        struct scatterlist      *sg;
+        struct page             *page;
+        void                    *data;
+        unsigned int            len_this_page;
+        unsigned int            len_this_segment;
+        unsigned int            offset;
+};
+
+/* Define sg_next is an inline routine now in case we want to change
+   scatterlist to a linked list later. */
+static inline struct scatterlist *sg_next(struct scatterlist *sg)
+{
+        return sg + 1;
+}
+
+static inline int scatterwalk_samebuf(struct scatter_walk *walk_in,
+                                      struct scatter_walk *walk_out)
+{
+        return walk_in->page == walk_out->page &&
+               walk_in->offset == walk_out->offset;
+}
+
+static inline int scatterwalk_across_pages(struct scatter_walk *walk,
+                                           unsigned int nbytes)
+{
+        return nbytes > walk->len_this_page;
+}
+
+static inline void scatterwalk_advance(struct scatter_walk *walk,
+                                       unsigned int nbytes)
+{
+        walk->data += nbytes;
+        walk->offset += nbytes;
+        walk->len_this_page -= nbytes;
+        walk->len_this_segment -= nbytes;
+}
+
+void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg);
+int scatterwalk_copychunks(void *buf, struct scatter_walk *walk, size_t nbytes, int out);
+void scatterwalk_map(struct scatter_walk *walk, int out);
+void scatterwalk_done(struct scatter_walk *walk, int out, int more);
+
+#endif  /* _CRYPTO_SCATTERWALK_H */