Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

Pull crypto update from Herbert Xu:
 "Here is the crypto update for 4.2:

  API:

   - Convert RNG interface to new style.

   - New AEAD interface with one SG list for AD and plain/cipher text.
     All external AEAD users have been converted.

   - New asymmetric key interface (akcipher).

  Algorithms:

   - Chacha20, Poly1305 and RFC7539 support.

   - New RSA implementation.

   - Jitter RNG.

   - DRBG is now seeded with both /dev/random and Jitter RNG.  If kernel
     pool isn't ready then DRBG will be reseeded when it is.

   - DRBG is now the default crypto API RNG, replacing krng.

   - 842 compression (previously part of powerpc nx driver).

  Drivers:

   - Accelerated SHA-512 for arm64.

   - New Marvell CESA driver that supports DMA and more algorithms.

   - Updated powerpc nx 842 support.

   - Added support for SEC1 hardware to talitos"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (292 commits)
  crypto: marvell/cesa - remove COMPILE_TEST dependency
  crypto: algif_aead - Temporarily disable all AEAD algorithms
  crypto: af_alg - Forbid the use internal algorithms
  crypto: echainiv - Only hold RNG during initialisation
  crypto: seqiv - Add compatibility support without RNG
  crypto: eseqiv - Offer normal cipher functionality without RNG
  crypto: chainiv - Offer normal cipher functionality without RNG
  crypto: user - Add CRYPTO_MSG_DELRNG
  crypto: user - Move cryptouser.h to uapi
  crypto: rng - Do not free default RNG when it becomes unused
  crypto: skcipher - Allow givencrypt to be NULL
  crypto: sahara - propagate the error on clk_disable_unprepare() failure
  crypto: rsa - fix invalid select for AKCIPHER
  crypto: picoxcell - Update to the current clk API
  crypto: nx - Check for bogus firmware properties
  crypto: marvell/cesa - add DT bindings documentation
  crypto: marvell/cesa - add support for Kirkwood and Dove SoCs
  crypto: marvell/cesa - add support for Orion SoCs
  crypto: marvell/cesa - add allhwsupport module parameter
  crypto: marvell/cesa - add support for all armada SoCs
  ...

1 files changed, 34 insertions, 11 deletions

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 3bd749c7..ea5815c5 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -54,7 +54,11 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
 		struct page *page;
 
 		page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT);
-		if (!PageSlab(page))
+		/* Test ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE first as
+		 * PageSlab cannot be optimised away per se due to
+		 * use of volatile pointer.
+		 */
+		if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE && !PageSlab(page))
 			flush_dcache_page(page);
 	}
 
@@ -104,22 +108,18 @@ void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
 			      unsigned int start, unsigned int nbytes, int out)
 {
 	struct scatter_walk walk;
-	unsigned int offset = 0;
+	struct scatterlist tmp[2];
 
 	if (!nbytes)
 		return;
 
-	for (;;) {
-		scatterwalk_start(&walk, sg);
-
-		if (start < offset + sg->length)
-			break;
+	sg = scatterwalk_ffwd(tmp, sg, start);
 
-		offset += sg->length;
-		sg = sg_next(sg);
-	}
+	if (sg_page(sg) == virt_to_page(buf) &&
+	    sg->offset == offset_in_page(buf))
+		return;
 
-	scatterwalk_advance(&walk, start - offset);
+	scatterwalk_start(&walk, sg);
 	scatterwalk_copychunks(buf, &walk, nbytes, out);
 	scatterwalk_done(&walk, out, 0);
 }
@@ -146,3 +146,26 @@ int scatterwalk_bytes_sglen(struct scatterlist *sg, int num_bytes)
 	return n;
 }
 EXPORT_SYMBOL_GPL(scatterwalk_bytes_sglen);
+
+struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
+				     struct scatterlist *src,
+				     unsigned int len)
+{
+	for (;;) {
+		if (!len)
+			return src;
+
+		if (src->length > len)
+			break;
+
+		len -= src->length;
+		src = sg_next(src);
+	}
+
+	sg_init_table(dst, 2);
+	sg_set_page(dst, sg_page(src), src->length - len, src->offset + len);
+	scatterwalk_crypto_chain(dst, sg_next(src), 0, 2);
+
+	return dst;
+}
+EXPORT_SYMBOL_GPL(scatterwalk_ffwd);