Date:	Mon, 2 Mar 2009 12:45:12 +0100
From:	Christian Hohnstaedt <chohnstaedt@...ominate.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	Russell King - ARM Linux <linux@....linux.org.uk>,
	karl@...amoto.org, chohnstaedt@...ominate.com,
	linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.arm.linux.org.uk
Subject: [PATCH] crypto: fix handling of sg buffers in ixp4xx driver


 - keep dma functions away from chained scatterlists.
   Use the existing scatterlist iteration inside the driver
   to call dma_map_single() for each chunk and avoid dma_map_sg().

Signed-off-by: Christian Hohnstaedt <chohnstaedt@...ominate.com>
Tested-By:  Karl Hiramoto <karl@...amoto.org>

---
 drivers/crypto/ixp4xx_crypto.c |  182 ++++++++++++++--------------------------
 1 files changed, 63 insertions(+), 119 deletions(-)

diff --git a/drivers/crypto/ixp4xx_crypto.c b/drivers/crypto/ixp4xx_crypto.c
index 2d637e0..fdcd0ab 100644
--- a/drivers/crypto/ixp4xx_crypto.c
+++ b/drivers/crypto/ixp4xx_crypto.c
@@ -101,6 +101,7 @@ struct buffer_desc {
 	u32 phys_addr;
 	u32 __reserved[4];
 	struct buffer_desc *next;
+	enum dma_data_direction dir;
 };
 
 struct crypt_ctl {
@@ -132,14 +133,10 @@ struct crypt_ctl {
 struct ablk_ctx {
 	struct buffer_desc *src;
 	struct buffer_desc *dst;
-	unsigned src_nents;
-	unsigned dst_nents;
 };
 
 struct aead_ctx {
 	struct buffer_desc *buffer;
-	unsigned short assoc_nents;
-	unsigned short src_nents;
 	struct scatterlist ivlist;
 	/* used when the hmac is not on one sg entry */
 	u8 *hmac_virt;
@@ -312,7 +309,7 @@ static struct crypt_ctl *get_crypt_desc_emerg(void)
 	}
 }
 
-static void free_buf_chain(struct buffer_desc *buf, u32 phys)
+static void free_buf_chain(struct device *dev, struct buffer_desc *buf,u32 phys)
 {
 	while (buf) {
 		struct buffer_desc *buf1;
@@ -320,6 +317,7 @@ static void free_buf_chain(struct buffer_desc *buf, u32 phys)
 
 		buf1 = buf->next;
 		phys1 = buf->phys_next;
+		dma_unmap_single(dev, buf->phys_next, buf->buf_len, buf->dir);
 		dma_pool_free(buffer_pool, buf, phys);
 		buf = buf1;
 		phys = phys1;
@@ -348,7 +346,6 @@ static void one_packet(dma_addr_t phys)
 	struct crypt_ctl *crypt;
 	struct ixp_ctx *ctx;
 	int failed;
-	enum dma_data_direction src_direction = DMA_BIDIRECTIONAL;
 
 	failed = phys & 0x1 ? -EBADMSG : 0;
 	phys &= ~0x3;
@@ -358,13 +355,8 @@ static void one_packet(dma_addr_t phys)
 	case CTL_FLAG_PERFORM_AEAD: {
 		struct aead_request *req = crypt->data.aead_req;
 		struct aead_ctx *req_ctx = aead_request_ctx(req);
-		dma_unmap_sg(dev, req->assoc, req_ctx->assoc_nents,
-				DMA_TO_DEVICE);
-		dma_unmap_sg(dev, &req_ctx->ivlist, 1, DMA_BIDIRECTIONAL);
-		dma_unmap_sg(dev, req->src, req_ctx->src_nents,
-				DMA_BIDIRECTIONAL);
 
-		free_buf_chain(req_ctx->buffer, crypt->src_buf);
+		free_buf_chain(dev, req_ctx->buffer, crypt->src_buf);
 		if (req_ctx->hmac_virt) {
 			finish_scattered_hmac(crypt);
 		}
@@ -374,16 +366,11 @@ static void one_packet(dma_addr_t phys)
 	case CTL_FLAG_PERFORM_ABLK: {
 		struct ablkcipher_request *req = crypt->data.ablk_req;
 		struct ablk_ctx *req_ctx = ablkcipher_request_ctx(req);
-		int nents;
+
 		if (req_ctx->dst) {
-			nents = req_ctx->dst_nents;
-			dma_unmap_sg(dev, req->dst, nents, DMA_FROM_DEVICE);
-			free_buf_chain(req_ctx->dst, crypt->dst_buf);
-			src_direction = DMA_TO_DEVICE;
+			free_buf_chain(dev, req_ctx->dst, crypt->dst_buf);
 		}
-		nents = req_ctx->src_nents;
-		dma_unmap_sg(dev, req->src, nents, src_direction);
-		free_buf_chain(req_ctx->src, crypt->src_buf);
+		free_buf_chain(dev, req_ctx->src, crypt->src_buf);
 		req->base.complete(&req->base, failed);
 		break;
 	}
@@ -748,56 +735,35 @@ static int setup_cipher(struct crypto_tfm *tfm, int encrypt,
 	return 0;
 }
 
-static int count_sg(struct scatterlist *sg, int nbytes)
+static struct buffer_desc *chainup_buffers(struct device *dev,
+		struct scatterlist *sg,	unsigned nbytes,
+		struct buffer_desc *buf, gfp_t flags,
+		enum dma_data_direction dir)
 {
-	int i;
-	for (i = 0; nbytes > 0; i++, sg = sg_next(sg))
-		nbytes -= sg->length;
-	return i;
-}
-
-static struct buffer_desc *chainup_buffers(struct scatterlist *sg,
-			unsigned nbytes, struct buffer_desc *buf, gfp_t flags)
-{
-	int nents = 0;
-
-	while (nbytes > 0) {
+	for (;nbytes > 0; sg = scatterwalk_sg_next(sg)) {
+		unsigned len = min(nbytes, sg->length);
 		struct buffer_desc *next_buf;
 		u32 next_buf_phys;
-		unsigned len = min(nbytes, sg_dma_len(sg));
+		void *ptr;
 
-		nents++;
 		nbytes -= len;
-		if (!buf->phys_addr) {
-			buf->phys_addr = sg_dma_address(sg);
-			buf->buf_len = len;
-			buf->next = NULL;
-			buf->phys_next = 0;
-			goto next;
-		}
-		/* Two consecutive chunks on one page may be handled by the old
-		 * buffer descriptor, increased by the length of the new one
-		 */
-		if (sg_dma_address(sg) == buf->phys_addr + buf->buf_len) {
-			buf->buf_len += len;
-			goto next;
-		}
+		ptr = page_address(sg_page(sg)) + sg->offset;
 		next_buf = dma_pool_alloc(buffer_pool, flags, &next_buf_phys);
-		if (!next_buf)
-			return NULL;
+		if (!next_buf) {
+			buf = NULL;
+			break;
+		}
+		sg_dma_address(sg) = dma_map_single(dev, ptr, len, dir);
 		buf->next = next_buf;
 		buf->phys_next = next_buf_phys;
-
 		buf = next_buf;
-		buf->next = NULL;
-		buf->phys_next = 0;
+
 		buf->phys_addr = sg_dma_address(sg);
 		buf->buf_len = len;
-next:
-		if (nbytes > 0) {
-			sg = sg_next(sg);
-		}
+		buf->dir = dir;
 	}
+	buf->next = NULL;
+	buf->phys_next = 0;
 	return buf;
 }
 
@@ -858,12 +824,12 @@ static int ablk_perform(struct ablkcipher_request *req, int encrypt)
 	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(req);
 	struct ixp_ctx *ctx = crypto_ablkcipher_ctx(tfm);
 	unsigned ivsize = crypto_ablkcipher_ivsize(tfm);
-	int ret = -ENOMEM;
 	struct ix_sa_dir *dir;
 	struct crypt_ctl *crypt;
-	unsigned int nbytes = req->nbytes, nents;
+	unsigned int nbytes = req->nbytes;
 	enum dma_data_direction src_direction = DMA_BIDIRECTIONAL;
 	struct ablk_ctx *req_ctx = ablkcipher_request_ctx(req);
+	struct buffer_desc src_hook;
 	gfp_t flags = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
 				GFP_KERNEL : GFP_ATOMIC;
 
@@ -876,7 +842,7 @@ static int ablk_perform(struct ablkcipher_request *req, int encrypt)
 
 	crypt = get_crypt_desc();
 	if (!crypt)
-		return ret;
+		return -ENOMEM;
 
 	crypt->data.ablk_req = req;
 	crypt->crypto_ctx = dir->npe_ctx_phys;
@@ -889,53 +855,41 @@ static int ablk_perform(struct ablkcipher_request *req, int encrypt)
 	BUG_ON(ivsize && !req->info);
 	memcpy(crypt->iv, req->info, ivsize);
 	if (req->src != req->dst) {
+		struct buffer_desc dst_hook;
 		crypt->mode |= NPE_OP_NOT_IN_PLACE;
-		nents = count_sg(req->dst, nbytes);
 		/* This was never tested by Intel
 		 * for more than one dst buffer, I think. */
-		BUG_ON(nents != 1);
-		req_ctx->dst_nents = nents;
-		dma_map_sg(dev, req->dst, nents, DMA_FROM_DEVICE);
-		req_ctx->dst = dma_pool_alloc(buffer_pool, flags,&crypt->dst_buf);
-		if (!req_ctx->dst)
-			goto unmap_sg_dest;
-		req_ctx->dst->phys_addr = 0;
-		if (!chainup_buffers(req->dst, nbytes, req_ctx->dst, flags))
+		BUG_ON(req->dst->length < nbytes);
+		req_ctx->dst = NULL;
+		if (!chainup_buffers(dev, req->dst, nbytes, &dst_hook,
+					flags, DMA_FROM_DEVICE))
 			goto free_buf_dest;
 		src_direction = DMA_TO_DEVICE;
+		req_ctx->dst = dst_hook.next;
+		crypt->dst_buf = dst_hook.phys_next;
 	} else {
 		req_ctx->dst = NULL;
-		req_ctx->dst_nents = 0;
 	}
-	nents = count_sg(req->src, nbytes);
-	req_ctx->src_nents = nents;
-	dma_map_sg(dev, req->src, nents, src_direction);
-
-	req_ctx->src = dma_pool_alloc(buffer_pool, flags, &crypt->src_buf);
-	if (!req_ctx->src)
-		goto unmap_sg_src;
-	req_ctx->src->phys_addr = 0;
-	if (!chainup_buffers(req->src, nbytes, req_ctx->src, flags))
+	req_ctx->src = NULL;
+	if (!chainup_buffers(dev, req->src, nbytes, &src_hook,
+				flags, src_direction))
 		goto free_buf_src;
 
+	req_ctx->src = src_hook.next;
+	crypt->src_buf = src_hook.phys_next;
 	crypt->ctl_flags |= CTL_FLAG_PERFORM_ABLK;
 	qmgr_put_entry(SEND_QID, crypt_virt2phys(crypt));
 	BUG_ON(qmgr_stat_overflow(SEND_QID));
 	return -EINPROGRESS;
 
 free_buf_src:
-	free_buf_chain(req_ctx->src, crypt->src_buf);
-unmap_sg_src:
-	dma_unmap_sg(dev, req->src, req_ctx->src_nents, src_direction);
+	free_buf_chain(dev, req_ctx->src, crypt->src_buf);
 free_buf_dest:
 	if (req->src != req->dst) {
-		free_buf_chain(req_ctx->dst, crypt->dst_buf);
-unmap_sg_dest:
-		dma_unmap_sg(dev, req->src, req_ctx->dst_nents,
-			DMA_FROM_DEVICE);
+		free_buf_chain(dev, req_ctx->dst, crypt->dst_buf);
 	}
 	crypt->ctl_flags = CTL_FLAG_UNUSED;
-	return ret;
+	return -ENOMEM;
 }
 
 static int ablk_encrypt(struct ablkcipher_request *req)
@@ -983,7 +937,7 @@ static int hmac_inconsistent(struct scatterlist *sg, unsigned start,
 			break;
 
 		offset += sg->length;
-		sg = sg_next(sg);
+		sg = scatterwalk_sg_next(sg);
 	}
 	return (start + nbytes > offset + sg->length);
 }
@@ -995,11 +949,10 @@ static int aead_perform(struct aead_request *req, int encrypt,
 	struct ixp_ctx *ctx = crypto_aead_ctx(tfm);
 	unsigned ivsize = crypto_aead_ivsize(tfm);
 	unsigned authsize = crypto_aead_authsize(tfm);
-	int ret = -ENOMEM;
 	struct ix_sa_dir *dir;
 	struct crypt_ctl *crypt;
-	unsigned int cryptlen, nents;
-	struct buffer_desc *buf;
+	unsigned int cryptlen;
+	struct buffer_desc *buf, src_hook;
 	struct aead_ctx *req_ctx = aead_request_ctx(req);
 	gfp_t flags = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
 				GFP_KERNEL : GFP_ATOMIC;
@@ -1020,7 +973,7 @@ static int aead_perform(struct aead_request *req, int encrypt,
 	}
 	crypt = get_crypt_desc();
 	if (!crypt)
-		return ret;
+		return -ENOMEM;
 
 	crypt->data.aead_req = req;
 	crypt->crypto_ctx = dir->npe_ctx_phys;
@@ -1039,31 +992,27 @@ static int aead_perform(struct aead_request *req, int encrypt,
 		BUG(); /* -ENOTSUP because of my lazyness */
 	}
 
-	req_ctx->buffer = dma_pool_alloc(buffer_pool, flags, &crypt->src_buf);
-	if (!req_ctx->buffer)
-		goto out;
-	req_ctx->buffer->phys_addr = 0;
 	/* ASSOC data */
-	nents = count_sg(req->assoc, req->assoclen);
-	req_ctx->assoc_nents = nents;
-	dma_map_sg(dev, req->assoc, nents, DMA_TO_DEVICE);
-	buf = chainup_buffers(req->assoc, req->assoclen, req_ctx->buffer,flags);
+	buf = chainup_buffers(dev, req->assoc, req->assoclen, &src_hook,
+		flags, DMA_TO_DEVICE);
+	req_ctx->buffer = src_hook.next;
+	crypt->src_buf = src_hook.phys_next;
 	if (!buf)
-		goto unmap_sg_assoc;
+		goto out;
 	/* IV */
 	sg_init_table(&req_ctx->ivlist, 1);
 	sg_set_buf(&req_ctx->ivlist, iv, ivsize);
-	dma_map_sg(dev, &req_ctx->ivlist, 1, DMA_BIDIRECTIONAL);
-	buf = chainup_buffers(&req_ctx->ivlist, ivsize, buf, flags);
+	buf = chainup_buffers(dev, &req_ctx->ivlist, ivsize, buf, flags,
+			DMA_BIDIRECTIONAL);
 	if (!buf)
-		goto unmap_sg_iv;
+		goto free_chain;
 	if (unlikely(hmac_inconsistent(req->src, cryptlen, authsize))) {
 		/* The 12 hmac bytes are scattered,
 		 * we need to copy them into a safe buffer */
 		req_ctx->hmac_virt = dma_pool_alloc(buffer_pool, flags,
 				&crypt->icv_rev_aes);
 		if (unlikely(!req_ctx->hmac_virt))
-			goto unmap_sg_iv;
+			goto free_chain;
 		if (!encrypt) {
 			scatterwalk_map_and_copy(req_ctx->hmac_virt,
 				req->src, cryptlen, authsize, 0);
@@ -1073,33 +1022,28 @@ static int aead_perform(struct aead_request *req, int encrypt,
 		req_ctx->hmac_virt = NULL;
 	}
 	/* Crypt */
-	nents = count_sg(req->src, cryptlen + authsize);
-	req_ctx->src_nents = nents;
-	dma_map_sg(dev, req->src, nents, DMA_BIDIRECTIONAL);
-	buf = chainup_buffers(req->src, cryptlen + authsize, buf, flags);
+	buf = chainup_buffers(dev, req->src, cryptlen + authsize, buf, flags,
+			DMA_BIDIRECTIONAL);
 	if (!buf)
-		goto unmap_sg_src;
+		goto free_hmac_virt;
 	if (!req_ctx->hmac_virt) {
 		crypt->icv_rev_aes = buf->phys_addr + buf->buf_len - authsize;
 	}
+
 	crypt->ctl_flags |= CTL_FLAG_PERFORM_AEAD;
 	qmgr_put_entry(SEND_QID, crypt_virt2phys(crypt));
 	BUG_ON(qmgr_stat_overflow(SEND_QID));
 	return -EINPROGRESS;
-unmap_sg_src:
-	dma_unmap_sg(dev, req->src, req_ctx->src_nents, DMA_BIDIRECTIONAL);
+free_hmac_virt:
 	if (req_ctx->hmac_virt) {
 		dma_pool_free(buffer_pool, req_ctx->hmac_virt,
 				crypt->icv_rev_aes);
 	}
-unmap_sg_iv:
-	dma_unmap_sg(dev, &req_ctx->ivlist, 1, DMA_BIDIRECTIONAL);
-unmap_sg_assoc:
-	dma_unmap_sg(dev, req->assoc, req_ctx->assoc_nents, DMA_TO_DEVICE);
-	free_buf_chain(req_ctx->buffer, crypt->src_buf);
+free_chain:
+	free_buf_chain(dev, req_ctx->buffer, crypt->src_buf);
 out:
 	crypt->ctl_flags = CTL_FLAG_UNUSED;
-	return ret;
+	return -ENOMEM;
 }
 
 static int aead_setup(struct crypto_aead *tfm, unsigned int authsize)
-- 
1.6.0.3

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