crypto: Remove duplicate code of SG helpers functions

crypto: Remove duplicate code of SG helpers functions

[LABBE Corentin]

Hello

This patch series try to remove some duplicate code of some SG helpers functions.
The first three patch replace custom functions by already in-tree helper functions.

The fourth add a new functions "sg_nents_for_len2" who is the same as
sg_nents_for_len with an additionnal arguments.
Note that I do not like the name, but I do not find any good name.

The last three patch use sg_nents_for_len2 for removing custom functions.

I send those patch as RFC since I do not own any of those hardware to test.

Regards

[PATCH 1/7] crypto: bfin: replace sg_count by sg_nents

[LABBE Corentin]

The sg_count function in bfin_crc.c is the same function as sg_nents.
Remove the duplicate code and use sg_nents() instead.

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 drivers/crypto/bfin_crc.c | 25 +++----------------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/drivers/crypto/bfin_crc.c b/drivers/crypto/bfin_crc.c
index 2f0b333..95b7396 100644
--- a/drivers/crypto/bfin_crc.c
+++ b/drivers/crypto/bfin_crc.c
@@ -96,26 +96,6 @@ struct bfin_crypto_crc_ctx {
 	u32			key;
 };
 
-
-/*
- * derive number of elements in scatterlist
- */
-static int sg_count(struct scatterlist *sg_list)
-{
-	struct scatterlist *sg = sg_list;
-	int sg_nents = 1;
-
-	if (sg_list == NULL)
-		return 0;
-
-	while (!sg_is_last(sg)) {
-		sg_nents++;
-		sg = sg_next(sg);
-	}
-
-	return sg_nents;
-}
-
 /*
  * get element in scatter list by given index
  */
@@ -160,7 +140,7 @@ static int bfin_crypto_crc_init(struct ahash_request *req)
 	}
 	spin_unlock_bh(&crc_list.lock);
 
-	if (sg_count(req->src) > CRC_MAX_DMA_DESC) {
+	if (sg_nents(req->src) > CRC_MAX_DMA_DESC) {
 		dev_dbg(ctx->crc->dev, "init: requested sg list is too big > %d\n",
 			CRC_MAX_DMA_DESC);
 		return -EINVAL;
@@ -376,7 +356,8 @@ static int bfin_crypto_crc_handle_queue(struct bfin_crypto_crc *crc,
 			ctx->sg = req->src;
 
 		/* Chop crc buffer size to multiple of 32 bit */
-		nsg = ctx->sg_nents = sg_count(ctx->sg);
+		nsg = sg_nents(ctx->sg);
+		ctx->sg_nents = nsg;
 		ctx->sg_buflen = ctx->buflast_len + req->nbytes;
 		ctx->bufnext_len = ctx->sg_buflen % 4;
 		ctx->sg_buflen &= ~0x3;
-- 
2.4.6

[PATCH 2/7] crypto: amcc replace get_sg_count by sg_nents_for_len

[LABBE Corentin]

The get_sg_count function of amcc is the same as sg_nents_for_len from
lib/scatterlist.c

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 drivers/crypto/amcc/crypto4xx_core.c | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/drivers/crypto/amcc/crypto4xx_core.c b/drivers/crypto/amcc/crypto4xx_core.c
index 192a8fa..27288fc 100644
--- a/drivers/crypto/amcc/crypto4xx_core.c
+++ b/drivers/crypto/amcc/crypto4xx_core.c
@@ -740,26 +740,6 @@ void crypto4xx_return_pd(struct crypto4xx_device *dev,
 	pd_uinfo->state = PD_ENTRY_FREE;
 }
 
-/*
- * derive number of elements in scatterlist
- * Shamlessly copy from talitos.c
- */
-static int get_sg_count(struct scatterlist *sg_list, int nbytes)
-{
-	struct scatterlist *sg = sg_list;
-	int sg_nents = 0;
-
-	while (nbytes) {
-		sg_nents++;
-		if (sg->length > nbytes)
-			break;
-		nbytes -= sg->length;
-		sg = sg_next(sg);
-	}
-
-	return sg_nents;
-}
-
 static u32 get_next_gd(u32 current)
 {
 	if (current != PPC4XX_LAST_GD)
@@ -800,7 +780,7 @@ u32 crypto4xx_build_pd(struct crypto_async_request *req,
 	u32 gd_idx = 0;
 
 	/* figure how many gd is needed */
-	num_gd = get_sg_count(src, datalen);
+	num_gd = sg_nents_for_len(src, datalen);
 	if (num_gd == 1)
 		num_gd = 0;
 
-- 
2.4.6

[PATCH 3/7] crypto: sahara replace sahara_sg_length with sg_nents_for_len

[LABBE Corentin]

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 drivers/crypto/sahara.c | 30 +++---------------------------
 1 file changed, 3 insertions(+), 27 deletions(-)

diff --git a/drivers/crypto/sahara.c b/drivers/crypto/sahara.c
index 820dc3a..cea2411 100644
--- a/drivers/crypto/sahara.c
+++ b/drivers/crypto/sahara.c
@@ -274,30 +274,6 @@ static u32 sahara_aes_data_link_hdr(struct sahara_dev *dev)
 			SAHARA_HDR_CHA_SKHA | SAHARA_HDR_PARITY_BIT;
 }
 
-static int sahara_sg_length(struct scatterlist *sg,
-			    unsigned int total)
-{
-	int sg_nb;
-	unsigned int len;
-	struct scatterlist *sg_list;
-
-	sg_nb = 0;
-	sg_list = sg;
-
-	while (total) {
-		len = min(sg_list->length, total);
-
-		sg_nb++;
-		total -= len;
-
-		sg_list = sg_next(sg_list);
-		if (!sg_list)
-			total = 0;
-	}
-
-	return sg_nb;
-}
-
 static char *sahara_err_src[16] = {
 	"No error",
 	"Header error",
@@ -502,8 +478,8 @@ static int sahara_hw_descriptor_create(struct sahara_dev *dev)
 		idx++;
 	}
 
-	dev->nb_in_sg = sahara_sg_length(dev->in_sg, dev->total);
-	dev->nb_out_sg = sahara_sg_length(dev->out_sg, dev->total);
+	dev->nb_in_sg = sg_nents_for_len(dev->in_sg, dev->total);
+	dev->nb_out_sg = sg_nents_for_len(dev->out_sg, dev->total);
 	if ((dev->nb_in_sg + dev->nb_out_sg) > SAHARA_MAX_HW_LINK) {
 		dev_err(dev->device, "not enough hw links (%d)\n",
 			dev->nb_in_sg + dev->nb_out_sg);
@@ -818,7 +794,7 @@ static int sahara_sha_hw_links_create(struct sahara_dev *dev,
 
 	dev->in_sg = rctx->in_sg;
 
-	dev->nb_in_sg = sahara_sg_length(dev->in_sg, rctx->total);
+	dev->nb_in_sg = sg_nents_for_len(dev->in_sg, rctx->total);
 	if ((dev->nb_in_sg) > SAHARA_MAX_HW_LINK) {
 		dev_err(dev->device, "not enough hw links (%d)\n",
 			dev->nb_in_sg + dev->nb_out_sg);
-- 
2.4.6

[PATCH 4/7] lib: introduce sg_nents_for_len2

[LABBE Corentin]

Some driver use a modified version of sg_nents_for_len with an
additional parameter bool *chained for knowing if the scatterlist is
chained or not.

So, for removing duplicate code, add sg_nents_for_len2 in
lib/scatterlist.c

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 include/linux/scatterlist.h |  1 +
 lib/scatterlist.c           | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 556ec1e..316c5c4 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -243,6 +243,7 @@ static inline void *sg_virt(struct scatterlist *sg)
 
 int sg_nents(struct scatterlist *sg);
 int sg_nents_for_len(struct scatterlist *sg, u64 len);
+int sg_nents_for_len2(struct scatterlist *sg, u64 len, bool *chained);
 struct scatterlist *sg_next(struct scatterlist *);
 struct scatterlist *sg_last(struct scatterlist *s, unsigned int);
 void sg_init_table(struct scatterlist *, unsigned int);
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index bafa993..0d1f746 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -90,6 +90,45 @@ int sg_nents_for_len(struct scatterlist *sg, u64 len)
 EXPORT_SYMBOL(sg_nents_for_len);
 
 /**
+ * sg_nents_for_len - return total count of entries in scatterlist
+ *                    needed to satisfy the supplied length
+ * @sg:		The scatterlist
+ * @len:	The total required length
+ * @chained	A pointer where to store if SG is chaind or not
+ *
+ * Description:
+ * Determines the number of entries in sg that are required to meet
+ * the supplied length, taking into acount chaining as well
+ *
+ * Returns:
+ *   the number of sg entries needed, negative error on failure
+ *
+ **/
+int sg_nents_for_len2(struct scatterlist *sg, u64 len, bool *chained)
+{
+	int nents;
+	u64 total;
+
+	if (chained)
+		*chained = false;
+
+	if (!len)
+		return 0;
+
+	for (nents = 0, total = 0; sg; sg = sg_next(sg)) {
+		nents++;
+		total += sg->length;
+		if (!sg_is_last(sg) && (sg + 1)->length == 0 && chained)
+			*chained = true;
+		if (total >= len)
+			return nents;
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL(sg_nents_for_len2);
+
+/**
  * sg_last - return the last scatterlist entry in a list
  * @sgl:	First entry in the scatterlist
  * @nents:	Number of entries in the scatterlist
-- 
2.4.6

Re: [PATCH 4/7] lib: introduce sg_nents_for_len2

[Herbert Xu]

On Thu, Sep 10, 2015 at 03:21:39PM +0200, LABBE Corentin wrote:
> Some driver use a modified version of sg_nents_for_len with an
> additional parameter bool *chained for knowing if the scatterlist is
> chained or not.
> 
> So, for removing duplicate code, add sg_nents_for_len2 in
> lib/scatterlist.c

This name is rather awkward.  Perhaps sg_nents_len_chained?

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 4/7] lib: introduce sg_nents_for_len2

[LABBE Corentin]

On Fri, Sep 18, 2015 at 07:53:00PM +0800, Herbert Xu wrote:
> On Thu, Sep 10, 2015 at 03:21:39PM +0200, LABBE Corentin wrote:
> > Some driver use a modified version of sg_nents_for_len with an
> > additional parameter bool *chained for knowing if the scatterlist is
> > chained or not.
> > 
> > So, for removing duplicate code, add sg_nents_for_len2 in
> > lib/scatterlist.c
> 
> This name is rather awkward.  Perhaps sg_nents_len_chained?

Perfect, thanks

I will send the modified patch series with this function name soon.

Regards

Re: [PATCH 4/7] lib: introduce sg_nents_for_len2

[Herbert Xu]

On Fri, Sep 18, 2015 at 02:20:48PM +0200, LABBE Corentin wrote:
>
> I will send the modified patch series with this function name soon.

You only need to resend patches 4-7.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: [PATCH 4/7] lib: introduce sg_nents_for_len2

[LABBE Corentin]

On Fri, Sep 18, 2015 at 08:22:13PM +0800, Herbert Xu wrote:
> On Fri, Sep 18, 2015 at 02:20:48PM +0200, LABBE Corentin wrote:
> >
> > I will send the modified patch series with this function name soon.
> 
> You only need to resend patches 4-7.
> 

Since I have used badly get_maintainer.pl, I need to resend all patchs with all proper recipient.
And I have respelled some patch. (like for sahara which have an empty commit log).

Regards

Re: [PATCH 4/7] lib: introduce sg_nents_for_len2

[Herbert Xu]

On Fri, Sep 18, 2015 at 02:42:34PM +0200, LABBE Corentin wrote:
> Since I have used badly get_maintainer.pl, I need to resend all patchs with all proper recipient.
> And I have respelled some patch. (like for sahara which have an empty commit log).

OK.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH 5/7] crypto: talitos replace sg_count with sg_nents_for_len2

[LABBE Corentin]

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 drivers/crypto/talitos.c | 34 ++++++++--------------------------
 1 file changed, 8 insertions(+), 26 deletions(-)

diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c
index 3b20a1b..aca6a6a 100644
--- a/drivers/crypto/talitos.c
+++ b/drivers/crypto/talitos.c
@@ -1234,26 +1234,6 @@ static int ipsec_esp(struct talitos_edesc *edesc, struct aead_request *areq,
 }
 
 /*
- * derive number of elements in scatterlist
- */
-static int sg_count(struct scatterlist *sg_list, int nbytes, bool *chained)
-{
-	struct scatterlist *sg = sg_list;
-	int sg_nents = 0;
-
-	*chained = false;
-	while (nbytes > 0 && sg) {
-		sg_nents++;
-		nbytes -= sg->length;
-		if (!sg_is_last(sg) && (sg + 1)->length == 0)
-			*chained = true;
-		sg = sg_next(sg);
-	}
-
-	return sg_nents;
-}
-
-/*
  * allocate and map the extended descriptor
  */
 static struct talitos_edesc *talitos_edesc_alloc(struct device *dev,
@@ -1287,16 +1267,17 @@ static struct talitos_edesc *talitos_edesc_alloc(struct device *dev,
 		iv_dma = dma_map_single(dev, iv, ivsize, DMA_TO_DEVICE);
 
 	if (!dst || dst == src) {
-		src_nents = sg_count(src, assoclen + cryptlen + authsize,
-				     &src_chained);
+		src_nents = sg_nents_for_len2(src,
+					      assoclen + cryptlen + authsize,
+					      &src_chained);
 		src_nents = (src_nents == 1) ? 0 : src_nents;
 		dst_nents = dst ? src_nents : 0;
 	} else { /* dst && dst != src*/
-		src_nents = sg_count(src, assoclen + cryptlen +
+		src_nents = sg_nents_for_len2(src, assoclen + cryptlen +
 					  (encrypt ? 0 : authsize),
 				     &src_chained);
 		src_nents = (src_nents == 1) ? 0 : src_nents;
-		dst_nents = sg_count(dst, assoclen + cryptlen +
+		dst_nents = sg_nents_for_len2(dst, assoclen + cryptlen +
 					  (encrypt ? authsize : 0),
 				     &dst_chained);
 		dst_nents = (dst_nents == 1) ? 0 : dst_nents;
@@ -1902,7 +1883,8 @@ static int ahash_process_req(struct ahash_request *areq, unsigned int nbytes)
 	if (!req_ctx->last && (nbytes + req_ctx->nbuf <= blocksize)) {
 		/* Buffer up to one whole block */
 		sg_copy_to_buffer(areq->src,
-				  sg_count(areq->src, nbytes, &chained),
+				  sg_nents_for_len2(areq->src, nbytes,
+						    &chained),
 				  req_ctx->buf + req_ctx->nbuf, nbytes);
 		req_ctx->nbuf += nbytes;
 		return 0;
@@ -1935,7 +1917,7 @@ static int ahash_process_req(struct ahash_request *areq, unsigned int nbytes)
 		req_ctx->psrc = areq->src;
 
 	if (to_hash_later) {
-		int nents = sg_count(areq->src, nbytes, &chained);
+		int nents = sg_nents_for_len2(areq->src, nbytes, &chained);
 		sg_pcopy_to_buffer(areq->src, nents,
 				      req_ctx->bufnext,
 				      to_hash_later,
-- 
2.4.6

[PATCH 6/7] crypto: qce replace qce_countsg with sg_nents_for_len2

[LABBE Corentin]

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 drivers/crypto/qce/ablkcipher.c |  4 ++--
 drivers/crypto/qce/dma.c        | 19 -------------------
 drivers/crypto/qce/dma.h        |  1 -
 drivers/crypto/qce/sha.c        |  2 +-
 4 files changed, 3 insertions(+), 23 deletions(-)

diff --git a/drivers/crypto/qce/ablkcipher.c b/drivers/crypto/qce/ablkcipher.c
index ad592de..0c589e7 100644
--- a/drivers/crypto/qce/ablkcipher.c
+++ b/drivers/crypto/qce/ablkcipher.c
@@ -80,10 +80,10 @@ qce_ablkcipher_async_req_handle(struct crypto_async_request *async_req)
 	dir_src = diff_dst ? DMA_TO_DEVICE : DMA_BIDIRECTIONAL;
 	dir_dst = diff_dst ? DMA_FROM_DEVICE : DMA_BIDIRECTIONAL;
 
-	rctx->src_nents = qce_countsg(req->src, req->nbytes,
+	rctx->src_nents = sg_nents_for_len2(req->src, req->nbytes,
 				      &rctx->src_chained);
 	if (diff_dst) {
-		rctx->dst_nents = qce_countsg(req->dst, req->nbytes,
+		rctx->dst_nents = sg_nents_for_len2(req->dst, req->nbytes,
 					      &rctx->dst_chained);
 	} else {
 		rctx->dst_nents = rctx->src_nents;
diff --git a/drivers/crypto/qce/dma.c b/drivers/crypto/qce/dma.c
index 378cb76..c18aaca 100644
--- a/drivers/crypto/qce/dma.c
+++ b/drivers/crypto/qce/dma.c
@@ -87,25 +87,6 @@ void qce_unmapsg(struct device *dev, struct scatterlist *sg, int nents,
 		dma_unmap_sg(dev, sg, nents, dir);
 }
 
-int qce_countsg(struct scatterlist *sglist, int nbytes, bool *chained)
-{
-	struct scatterlist *sg = sglist;
-	int nents = 0;
-
-	if (chained)
-		*chained = false;
-
-	while (nbytes > 0 && sg) {
-		nents++;
-		nbytes -= sg->length;
-		if (!sg_is_last(sg) && (sg + 1)->length == 0 && chained)
-			*chained = true;
-		sg = sg_next(sg);
-	}
-
-	return nents;
-}
-
 struct scatterlist *
 qce_sgtable_add(struct sg_table *sgt, struct scatterlist *new_sgl)
 {
diff --git a/drivers/crypto/qce/dma.h b/drivers/crypto/qce/dma.h
index 65bedb8..4653e2d8 100644
--- a/drivers/crypto/qce/dma.h
+++ b/drivers/crypto/qce/dma.h
@@ -49,7 +49,6 @@ int qce_dma_prep_sgs(struct qce_dma_data *dma, struct scatterlist *sg_in,
 		     dma_async_tx_callback cb, void *cb_param);
 void qce_dma_issue_pending(struct qce_dma_data *dma);
 int qce_dma_terminate_all(struct qce_dma_data *dma);
-int qce_countsg(struct scatterlist *sg_list, int nbytes, bool *chained);
 void qce_unmapsg(struct device *dev, struct scatterlist *sg, int nents,
 		 enum dma_data_direction dir, bool chained);
 int qce_mapsg(struct device *dev, struct scatterlist *sg, int nents,
diff --git a/drivers/crypto/qce/sha.c b/drivers/crypto/qce/sha.c
index be2f504..86fae62 100644
--- a/drivers/crypto/qce/sha.c
+++ b/drivers/crypto/qce/sha.c
@@ -92,7 +92,7 @@ static int qce_ahash_async_req_handle(struct crypto_async_request *async_req)
 		rctx->authklen = AES_KEYSIZE_128;
 	}
 
-	rctx->src_nents = qce_countsg(req->src, req->nbytes,
+	rctx->src_nents = sg_nents_for_len2(req->src, req->nbytes,
 				      &rctx->src_chained);
 	ret = qce_mapsg(qce->dev, req->src, rctx->src_nents, DMA_TO_DEVICE,
 			rctx->src_chained);
-- 
2.4.6

[PATCH 7/7] crypto: caam replace __sg_count with sg_nents_for_len2

[LABBE Corentin]

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 drivers/crypto/caam/caamhash.c   | 14 ++++++++------
 drivers/crypto/caam/sg_sw_sec4.h | 20 +-------------------
 2 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/drivers/crypto/caam/caamhash.c b/drivers/crypto/caam/caamhash.c
index 94433b9..b429595 100644
--- a/drivers/crypto/caam/caamhash.c
+++ b/drivers/crypto/caam/caamhash.c
@@ -797,8 +797,9 @@ static int ahash_update_ctx(struct ahash_request *req)
 	to_hash = in_len - *next_buflen;
 
 	if (to_hash) {
-		src_nents = __sg_count(req->src, req->nbytes - (*next_buflen),
-				       &chained);
+		src_nents = sg_nents_for_len2(req->src,
+					      req->nbytes - (*next_buflen),
+					      &chained);
 		sec4_sg_src_index = 1 + (*buflen ? 1 : 0);
 		sec4_sg_bytes = (sec4_sg_src_index + src_nents) *
 				 sizeof(struct sec4_sg_entry);
@@ -1000,7 +1001,7 @@ static int ahash_finup_ctx(struct ahash_request *req)
 	int ret = 0;
 	int sh_len;
 
-	src_nents = __sg_count(req->src, req->nbytes, &chained);
+	src_nents = sg_nents_for_len2(req->src, req->nbytes, &chained);
 	sec4_sg_src_index = 1 + (buflen ? 1 : 0);
 	sec4_sg_bytes = (sec4_sg_src_index + src_nents) *
 			 sizeof(struct sec4_sg_entry);
@@ -1236,8 +1237,9 @@ static int ahash_update_no_ctx(struct ahash_request *req)
 	to_hash = in_len - *next_buflen;
 
 	if (to_hash) {
-		src_nents = __sg_count(req->src, req->nbytes - (*next_buflen),
-				       &chained);
+		src_nents = sg_nents_for_len2(req->src,
+					      req->nbytes - (*next_buflen),
+					      &chained);
 		sec4_sg_bytes = (1 + src_nents) *
 				sizeof(struct sec4_sg_entry);
 
@@ -1347,7 +1349,7 @@ static int ahash_finup_no_ctx(struct ahash_request *req)
 	int sh_len;
 	int ret = 0;
 
-	src_nents = __sg_count(req->src, req->nbytes, &chained);
+	src_nents = sg_nents_for_len2(req->src, req->nbytes, &chained);
 	sec4_sg_src_index = 2;
 	sec4_sg_bytes = (sec4_sg_src_index + src_nents) *
 			 sizeof(struct sec4_sg_entry);
diff --git a/drivers/crypto/caam/sg_sw_sec4.h b/drivers/crypto/caam/sg_sw_sec4.h
index 18cd6d1..a486efc 100644
--- a/drivers/crypto/caam/sg_sw_sec4.h
+++ b/drivers/crypto/caam/sg_sw_sec4.h
@@ -69,29 +69,11 @@ static inline struct sec4_sg_entry *sg_to_sec4_sg_len(
 	return sec4_sg_ptr - 1;
 }
 
-/* count number of elements in scatterlist */
-static inline int __sg_count(struct scatterlist *sg_list, int nbytes,
-			     bool *chained)
-{
-	struct scatterlist *sg = sg_list;
-	int sg_nents = 0;
-
-	while (nbytes > 0) {
-		sg_nents++;
-		nbytes -= sg->length;
-		if (!sg_is_last(sg) && (sg + 1)->length == 0)
-			*chained = true;
-		sg = sg_next(sg);
-	}
-
-	return sg_nents;
-}
-
 /* derive number of elements in scatterlist, but return 0 for 1 */
 static inline int sg_count(struct scatterlist *sg_list, int nbytes,
 			     bool *chained)
 {
-	int sg_nents = __sg_count(sg_list, nbytes, chained);
+	int sg_nents = sg_nents_for_len2(sg_list, nbytes, chained);
 
 	if (likely(sg_nents == 1))
 		return 0;
-- 
2.4.6