crypto: scatterwalk - Add scatterwalk_crypto_chain helper

A lot of crypto algorithms implement their own chaining function.
So add a generic one that can be used from all the algorithms that
need scatterlist chaining.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 833d208c25d6..4fd95a323beb 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -68,6 +68,21 @@ static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
         return (++sg)->length ? sg : (void *)sg_page(sg);
 }
 
+static inline void scatterwalk_crypto_chain(struct scatterlist *head,
+                                            struct scatterlist *sg,
+                                            int chain, int num)
+{
+        if (chain) {
+                head->length += sg->length;
+                sg = scatterwalk_sg_next(sg);
+        }
+
+        if (sg)
+                scatterwalk_sg_chain(head, num, sg);
+        else
+                sg_mark_end(head);
+}
+
 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
                                                 struct scatter_walk *walk_out)
 {