diff --git a/crypto/cipher.c b/crypto/cipher.c
index d8ca0ec..3264617 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -45,15 +45,10 @@
 	u8 buffer[bsize * 2 + alignmask];
 	u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 	u8 *dst = src + bsize;
-	unsigned int n;
 
-	n = scatterwalk_copychunks(src, in, bsize, 0);
-	scatterwalk_advance(in, n);
-
+	scatterwalk_copychunks(src, in, bsize, 0);
 	desc->prfn(desc, dst, src, bsize);
-
-	n = scatterwalk_copychunks(dst, out, bsize, 1);
-	scatterwalk_advance(out, n);
+	scatterwalk_copychunks(dst, out, bsize, 1);
 
 	return bsize;
 }
@@ -64,12 +59,16 @@
 				      unsigned int nbytes, u8 *tmp)
 {
 	u8 *src, *dst;
+	u8 *real_src, *real_dst;
 
-	src = in->data;
-	dst = scatterwalk_samebuf(in, out) ? src : out->data;
+	real_src = scatterwalk_map(in, 0);
+	real_dst = scatterwalk_map(out, 1);
+
+	src = real_src;
+	dst = scatterwalk_samebuf(in, out) ? src : real_dst;
 
 	if (tmp) {
-		memcpy(tmp, in->data, nbytes);
+		memcpy(tmp, src, nbytes);
 		src = tmp;
 		dst = tmp;
 	}
@@ -77,7 +76,10 @@
 	nbytes = desc->prfn(desc, dst, src, nbytes);
 
 	if (tmp)
-		memcpy(out->data, tmp, nbytes);
+		memcpy(real_dst, tmp, nbytes);
+
+	scatterwalk_unmap(real_src, 0);
+	scatterwalk_unmap(real_dst, 1);
 
 	scatterwalk_advance(in, nbytes);
 	scatterwalk_advance(out, nbytes);
@@ -126,9 +128,6 @@
 			tmp = (u8 *)buffer;
 		}
 
-		scatterwalk_map(&walk_in, 0);
-		scatterwalk_map(&walk_out, 1);
-
 		n = scatterwalk_clamp(&walk_in, n);
 		n = scatterwalk_clamp(&walk_out, n);
 
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 2953e2c..35172d3 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -15,9 +15,11 @@
  */
 #include <linux/kernel.h>
 #include <linux/mm.h>
+#include <linux/module.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
-#include <asm/scatterlist.h>
+#include <linux/scatterlist.h>
+
 #include "internal.h"
 #include "scatterwalk.h"
 
@@ -27,88 +29,77 @@
 	KM_SOFTIRQ0,
 	KM_SOFTIRQ1,
 };
+EXPORT_SYMBOL_GPL(crypto_km_types);
 
-static void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
+static inline void memcpy_dir(void *buf, void *sgdata, size_t nbytes, int out)
 {
-	if (out)
-		memcpy(sgdata, buf, nbytes);
-	else
-		memcpy(buf, sgdata, nbytes);
+	void *src = out ? buf : sgdata;
+	void *dst = out ? sgdata : buf;
+
+	memcpy(dst, src, nbytes);
 }
 
 void scatterwalk_start(struct scatter_walk *walk, struct scatterlist *sg)
 {
-	unsigned int rest_of_page;
-
 	walk->sg = sg;
 
-	walk->page = sg->page;
-	walk->len_this_segment = sg->length;
-
 	BUG_ON(!sg->length);
 
-	rest_of_page = PAGE_CACHE_SIZE - (sg->offset & (PAGE_CACHE_SIZE - 1));
-	walk->len_this_page = min(sg->length, rest_of_page);
 	walk->offset = sg->offset;
 }
+EXPORT_SYMBOL_GPL(scatterwalk_start);
 
-void scatterwalk_map(struct scatter_walk *walk, int out)
+void *scatterwalk_map(struct scatter_walk *walk, int out)
 {
-	walk->data = crypto_kmap(walk->page, out) + walk->offset;
+	return crypto_kmap(scatterwalk_page(walk), out) +
+	       offset_in_page(walk->offset);
 }
-
-static inline void scatterwalk_unmap(struct scatter_walk *walk, int out)
-{
-	/* walk->data may be pointing the first byte of the next page;
-	   however, we know we transfered at least one byte.  So,
-	   walk->data - 1 will be a virtual address in the mapped page. */
-	crypto_kunmap(walk->data - 1, out);
-}
+EXPORT_SYMBOL_GPL(scatterwalk_map);
 
 static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
 				 unsigned int more)
 {
 	if (out)
-		flush_dcache_page(walk->page);
+		flush_dcache_page(scatterwalk_page(walk));
 
 	if (more) {
-		walk->len_this_segment -= walk->len_this_page;
-
-		if (walk->len_this_segment) {
-			walk->page++;
-			walk->len_this_page = min(walk->len_this_segment,
-						  (unsigned)PAGE_CACHE_SIZE);
-			walk->offset = 0;
-		}
-		else
+		walk->offset += PAGE_SIZE - 1;
+		walk->offset &= PAGE_MASK;
+		if (walk->offset >= walk->sg->offset + walk->sg->length)
 			scatterwalk_start(walk, sg_next(walk->sg));
 	}
 }
 
 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
 {
-	scatterwalk_unmap(walk, out);
-	if (walk->len_this_page == 0 || !more)
+	if (!offset_in_page(walk->offset) || !more)
 		scatterwalk_pagedone(walk, out, more);
 }
+EXPORT_SYMBOL_GPL(scatterwalk_done);
 
-/*
- * Do not call this unless the total length of all of the fragments
- * has been verified as multiple of the block size.
- */
-int scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
-			   size_t nbytes, int out)
+void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
+			    size_t nbytes, int out)
 {
-	while (nbytes > walk->len_this_page) {
-		memcpy_dir(buf, walk->data, walk->len_this_page, out);
-		buf += walk->len_this_page;
-		nbytes -= walk->len_this_page;
+	for (;;) {
+		unsigned int len_this_page = scatterwalk_pagelen(walk);
+		u8 *vaddr;
 
-		scatterwalk_unmap(walk, out);
+		if (len_this_page > nbytes)
+			len_this_page = nbytes;
+
+		vaddr = scatterwalk_map(walk, out);
+		memcpy_dir(buf, vaddr, len_this_page, out);
+		scatterwalk_unmap(vaddr, out);
+
+		if (nbytes == len_this_page)
+			break;
+
+		buf += len_this_page;
+		nbytes -= len_this_page;
+
 		scatterwalk_pagedone(walk, out, 1);
-		scatterwalk_map(walk, out);
 	}
 
-	memcpy_dir(buf, walk->data, nbytes, out);
-	return nbytes;
+	scatterwalk_advance(walk, nbytes);
 }
+EXPORT_SYMBOL_GPL(scatterwalk_copychunks);
diff --git a/crypto/scatterwalk.h b/crypto/scatterwalk.h
index e79925c..ace595a 100644
--- a/crypto/scatterwalk.h
+++ b/crypto/scatterwalk.h
@@ -14,17 +14,11 @@
 
 #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;
-};
+#include <linux/mm.h>
+#include <linux/scatterlist.h>
+
+#include "internal.h"
 
 /* Define sg_next is an inline routine now in case we want to change
    scatterlist to a linked list later. */
@@ -33,26 +27,31 @@
 	return sg + 1;
 }
 
-static inline int scatterwalk_samebuf(struct scatter_walk *walk_in,
-				      struct scatter_walk *walk_out)
+static inline unsigned long 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;
+	return !(((walk_in->sg->page - walk_out->sg->page) << PAGE_SHIFT) +
+		 (int)(walk_in->offset - walk_out->offset));
+}
+
+static inline unsigned int scatterwalk_pagelen(struct scatter_walk *walk)
+{
+	unsigned int len = walk->sg->offset + walk->sg->length - walk->offset;
+	unsigned int len_this_page = offset_in_page(~walk->offset) + 1;
+	return len_this_page > len ? len : len_this_page;
 }
 
 static inline unsigned int scatterwalk_clamp(struct scatter_walk *walk,
 					     unsigned int nbytes)
 {
-	return nbytes > walk->len_this_page ? walk->len_this_page : nbytes;
+	unsigned int len_this_page = scatterwalk_pagelen(walk);
+	return nbytes > len_this_page ? len_this_page : nbytes;
 }
 
 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;
 }
 
 static inline unsigned int scatterwalk_aligned(struct scatter_walk *walk,
@@ -61,9 +60,20 @@
 	return !(walk->offset & alignmask);
 }
 
+static inline struct page *scatterwalk_page(struct scatter_walk *walk)
+{
+	return walk->sg->page + (walk->offset >> PAGE_SHIFT);
+}
+
+static inline void scatterwalk_unmap(void *vaddr, int out)
+{
+	crypto_kunmap(vaddr, out);
+}
+
 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_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 */
diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
index 6f9fb27..f21ae67 100644
--- a/include/crypto/algapi.h
+++ b/include/crypto/algapi.h
@@ -50,6 +50,11 @@
 	struct crypto_instance *inst;
 };
 
+struct scatter_walk {
+	struct scatterlist *sg;
+	unsigned int offset;
+};
+
 int crypto_register_template(struct crypto_template *tmpl);
 void crypto_unregister_template(struct crypto_template *tmpl);
 struct crypto_template *crypto_lookup_template(const char *name);