2.6.26-rc1

 lib

diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index acca490..b80c211 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -8,6 +8,7 @@
  */
 #include <linux/module.h>
 #include <linux/scatterlist.h>
+#include <linux/highmem.h>
 
 /**
  * sg_next - return the next scatterlist entry in a list
@@ -292,3 +293,104 @@ int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask)
    return ret;
 }
 EXPORT_SYMBOL(sg_alloc_table);
+
+/**
+ * sg_copy_buffer - Copy data between a linear buffer and an SG list
+ * @sgl:       The SG list
+ * @nents:       Number of SG entries
+ * @buf:       Where to copy from
+ * @buflen:       The number of bytes to copy
+ * @to_buffer:        transfer direction (non zero == from an sg list to a
+ *           buffer, 0 == from a buffer to an sg list
+ *
+ * Returns the number of copied bytes.
+ *
+ **/
+static size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents,
+              void *buf, size_t buflen, int to_buffer)
+{
+   struct scatterlist *sg;
+   size_t buf_off = 0;
+   int i;
+
+   WARN_ON(!irqs_disabled());
+
+   for_each_sg(sgl, sg, nents, i) {
+      struct page *page;
+      int n = 0;
+      unsigned int sg_off = sg->offset;
+      unsigned int sg_copy = sg->length;
+
+      if (sg_copy > buflen)
+         sg_copy = buflen;
+      buflen -= sg_copy;
+
+      while (sg_copy > 0) {
+         unsigned int page_copy;
+         void *p;
+
+         page_copy = PAGE_SIZE - sg_off;
+         if (page_copy > sg_copy)
+            page_copy = sg_copy;
+
+         page = nth_page(sg_page(sg), n);
+         p = kmap_atomic(page, KM_BIO_SRC_IRQ);
+
+         if (to_buffer)
+            memcpy(buf + buf_off, p + sg_off, page_copy);
+         else {
+            memcpy(p + sg_off, buf + buf_off, page_copy);
+            flush_kernel_dcache_page(page);
+         }
+
+         kunmap_atomic(p, KM_BIO_SRC_IRQ);
+
+         buf_off += page_copy;
+         sg_off += page_copy;
+         if (sg_off == PAGE_SIZE) {
+            sg_off = 0;
+            n++;
+         }
+         sg_copy -= page_copy;
+      }
+
+      if (!buflen)
+         break;
+   }
+
+   return buf_off;
+}
+
+/**
+ * sg_copy_from_buffer - Copy from a linear buffer to an SG list
+ * @sgl:       The SG list
+ * @nents:       Number of SG entries
+ * @buf:       Where to copy from
+ * @buflen:       The number of bytes to copy
+ *
+ * Returns the number of copied bytes.
+ *
+ **/
+size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents,
+            void *buf, size_t buflen)
+{
+   return sg_copy_buffer(sgl, nents, buf, buflen, 0);
+}
+EXPORT_SYMBOL(sg_copy_from_buffer);
+
+/**
+ * sg_copy_to_buffer - Copy from an SG list to a linear buffer
+ * @sgl:       The SG list
+ * @nents:       Number of SG entries
+ * @buf:       Where to copy to
+ * @buflen:       The number of bytes to copy
+ *
+ * Returns the number of copied bytes.
+ *
+ **/
+size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
+          void *buf, size_t buflen)
+{
+   return sg_copy_buffer(sgl, nents, buf, buflen, 1);
+}
+EXPORT_SYMBOL(sg_copy_to_buffer);