crypto: skcipher - introduce walksize attribute for SIMD algos

In some cases, SIMD algorithms can only perform optimally when
allowed to operate on multiple input blocks in parallel. This is
especially true for bit slicing algorithms, which typically take
the same amount of time processing a single block or 8 blocks in
parallel. However, other SIMD algorithms may benefit as well from
bigger strides.

So add a walksize attribute to the skcipher algorithm definition, and
wire it up to the skcipher walk API. To avoid confusion between the
skcipher and AEAD attributes, rename the skcipher_walk chunksize
attribute to 'stride', and set it from the walksize (in the skcipher
case) or from the chunksize (in the AEAD case).

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 12 insertions, 8 deletions

diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 0e1e6c3..6ee6a15 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -185,12 +185,12 @@ void skcipher_walk_complete(struct skcipher_walk *walk, int err)
 		data = p->data;
 		if (!data) {
 			data = PTR_ALIGN(&p->buffer[0], walk->alignmask + 1);
-			data = skcipher_get_spot(data, walk->chunksize);
+			data = skcipher_get_spot(data, walk->stride);
 		}
 
 		scatterwalk_copychunks(data, &p->dst, p->len, 1);
 
-		if (offset_in_page(p->data) + p->len + walk->chunksize >
+		if (offset_in_page(p->data) + p->len + walk->stride >
 		    PAGE_SIZE)
 			free_page((unsigned long)p->data);
 
@@ -299,7 +299,7 @@ static int skcipher_next_copy(struct skcipher_walk *walk)
 	p->len = walk->nbytes;
 	skcipher_queue_write(walk, p);
 
-	if (offset_in_page(walk->page) + walk->nbytes + walk->chunksize >
+	if (offset_in_page(walk->page) + walk->nbytes + walk->stride >
 	    PAGE_SIZE)
 		walk->page = NULL;
 	else
@@ -344,7 +344,7 @@ static int skcipher_walk_next(struct skcipher_walk *walk)
 			 SKCIPHER_WALK_DIFF);
 
 	n = walk->total;
-	bsize = min(walk->chunksize, max(n, walk->blocksize));
+	bsize = min(walk->stride, max(n, walk->blocksize));
 	n = scatterwalk_clamp(&walk->in, n);
 	n = scatterwalk_clamp(&walk->out, n);
 
@@ -393,7 +393,7 @@ static int skcipher_copy_iv(struct skcipher_walk *walk)
 	unsigned a = crypto_tfm_ctx_alignment() - 1;
 	unsigned alignmask = walk->alignmask;
 	unsigned ivsize = walk->ivsize;
-	unsigned bs = walk->chunksize;
+	unsigned bs = walk->stride;
 	unsigned aligned_bs;
 	unsigned size;
 	u8 *iv;
@@ -463,7 +463,7 @@ static int skcipher_walk_skcipher(struct skcipher_walk *walk,
 		       SKCIPHER_WALK_SLEEP : 0;
 
 	walk->blocksize = crypto_skcipher_blocksize(tfm);
-	walk->chunksize = crypto_skcipher_chunksize(tfm);
+	walk->stride = crypto_skcipher_walksize(tfm);
 	walk->ivsize = crypto_skcipher_ivsize(tfm);
 	walk->alignmask = crypto_skcipher_alignmask(tfm);
 
@@ -525,7 +525,7 @@ static int skcipher_walk_aead_common(struct skcipher_walk *walk,
 		walk->flags &= ~SKCIPHER_WALK_SLEEP;
 
 	walk->blocksize = crypto_aead_blocksize(tfm);
-	walk->chunksize = crypto_aead_chunksize(tfm);
+	walk->stride = crypto_aead_chunksize(tfm);
 	walk->ivsize = crypto_aead_ivsize(tfm);
 	walk->alignmask = crypto_aead_alignmask(tfm);
 
@@ -821,6 +821,7 @@ static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
 	seq_printf(m, "max keysize  : %u\n", skcipher->max_keysize);
 	seq_printf(m, "ivsize       : %u\n", skcipher->ivsize);
 	seq_printf(m, "chunksize    : %u\n", skcipher->chunksize);
+	seq_printf(m, "walksize     : %u\n", skcipher->walksize);
 }
 
 #ifdef CONFIG_NET
@@ -893,11 +894,14 @@ static int skcipher_prepare_alg(struct skcipher_alg *alg)
 {
 	struct crypto_alg *base = &alg->base;
 
-	if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8)
+	if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8 ||
+	    alg->walksize > PAGE_SIZE / 8)
 		return -EINVAL;
 
 	if (!alg->chunksize)
 		alg->chunksize = base->cra_blocksize;
+	if (!alg->walksize)
+		alg->walksize = alg->chunksize;
 
 	base->cra_type = &crypto_skcipher_type2;
 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;