From b2ab4a57b018aafbba35bff088218f5cc3d2142e Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Wed, 5 Dec 2007 20:59:25 +1100
Subject: [PATCH] [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>
---
 crypto/digest.c              |  2 +-
 crypto/gcm.c                 |  2 +-
 crypto/hmac.c                |  3 ++-
 crypto/scatterwalk.c         |  4 ++--
 include/crypto/scatterwalk.h | 11 +++++++++++
 5 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/crypto/digest.c b/crypto/digest.c
index 52845f53f8e1b..6fd43bddd545e 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 27483f361e802..502da929a5fc8 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 34c3706db85d4..a1d016a50e7de 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 12d19019e178e..297e19d13c4e6 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 07b6f17122d2e..bd62431c33bdb 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)
 {
-- 
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