[CRYPTO] scatterwalk: Restore custom sg chaining for now

Unfortunately the generic chaining hasn't been ported to all architectures
yet, and notably not s390.  So this patch restores the chainging that we've
been using previously which does work everywhere.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

5 files changed, 17 insertions, 5 deletions

diff --git a/crypto/digest.c b/crypto/digest.c
index 52845f53f8e1..6fd43bddd545 100644
--- a/crypto/digest.c
+++ b/crypto/digest.c
@@ -75,7 +75,7 @@ static int update2(struct hash_desc *desc,
 
                 if (!nbytes)
                         break;
-                sg = sg_next(sg);
+                sg = scatterwalk_sg_next(sg);
         }
 
         return 0;
diff --git a/crypto/gcm.c b/crypto/gcm.c
index 27483f361e80..502da929a5fc 100644
--- a/crypto/gcm.c
+++ b/crypto/gcm.c
@@ -100,7 +100,7 @@ static void crypto_gcm_ghash_update_sg(struct crypto_gcm_ghash_ctx *ctx,
                 n = scatterwalk_clamp(&walk, len);
 
                 if (!n) {
-                        scatterwalk_start(&walk, sg_next(walk.sg));
+                        scatterwalk_start(&walk, scatterwalk_sg_next(walk.sg));
                         n = scatterwalk_clamp(&walk, len);
                 }
 
diff --git a/crypto/hmac.c b/crypto/hmac.c
index 34c3706db85d..a1d016a50e7d 100644
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -17,6 +17,7 @@
  */
 
 #include <crypto/algapi.h>
+#include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -160,7 +161,7 @@ static int hmac_digest(struct hash_desc *pdesc, struct scatterlist *sg,
 
         sg_init_table(sg1, 2);
         sg_set_buf(sg1, ipad, bs);
-        sg_chain(sg1, 2, sg);
+        scatterwalk_sg_chain(sg1, 2, sg);
 
         sg_init_table(sg2, 1);
         sg_set_buf(sg2, opad, bs + ds);
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 12d19019e178..297e19d13c4e 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -61,7 +61,7 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
                 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));
+                        scatterwalk_start(walk, scatterwalk_sg_next(walk->sg));
         }
 }
 
@@ -112,7 +112,7 @@ void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
                         break;
 
                 offset += sg->length;
-                sg = sg_next(sg);
+                sg = scatterwalk_sg_next(sg);
         }
 
         scatterwalk_advance(&walk, start - offset);
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 07b6f17122d2..bd62431c33bd 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -52,6 +52,17 @@ static inline void crypto_yield(u32 flags)
                 cond_resched();
 }
 
+static inline void scatterwalk_sg_chain(struct scatterlist *sg1, int num,
+                                        struct scatterlist *sg2)
+{
+        sg_set_page(&sg1[num - 1], (void *)sg2, 0, 0);
+}
+
+static inline struct scatterlist *scatterwalk_sg_next(struct scatterlist *sg)
+{
+        return (++sg)->length ? sg : (void *)sg_page(sg);
+}
+
 static inline unsigned long scatterwalk_samebuf(struct scatter_walk *walk_in,
                                                 struct scatter_walk *walk_out)
 {