linux-kernel - [PATCH 4/4] crypto: s5p-sss - Constify pointed data (arguments and local variables)

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Date:   Thu,  1 Mar 2018 21:50:13 +0100
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Vladimir Zapolskiy <vz@...ia.com>,
        Kamil Konieczny <k.konieczny@...tner.samsung.com>,
        Tero Kristo <t-kristo@...com>, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org
Subject: [PATCH 4/4] crypto: s5p-sss - Constify pointed data (arguments and local variables)

Improve the code (safety and readability) by indicating that data passed
through pointer is not modified.  This adds const keyword in many places,
most notably:
 - the driver data (pointer to struct samsung_aes_variant),
 - scatterlist addresses written as value to device registers,
 - key and IV arrays.

Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
---
 drivers/crypto/s5p-sss.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/crypto/s5p-sss.c b/drivers/crypto/s5p-sss.c
index d7c8163e5068..bf7163042569 100644
--- a/drivers/crypto/s5p-sss.c
+++ b/drivers/crypto/s5p-sss.c
@@ -404,29 +404,31 @@ static const struct of_device_id s5p_sss_dt_match[] = {
 };
 MODULE_DEVICE_TABLE(of, s5p_sss_dt_match);
 
-static inline struct samsung_aes_variant *find_s5p_sss_version
-				   (struct platform_device *pdev)
+static inline const struct samsung_aes_variant *find_s5p_sss_version
+				   (const struct platform_device *pdev)
 {
 	if (IS_ENABLED(CONFIG_OF) && (pdev->dev.of_node)) {
 		const struct of_device_id *match;
 
 		match = of_match_node(s5p_sss_dt_match,
 					pdev->dev.of_node);
-		return (struct samsung_aes_variant *)match->data;
+		return (const struct samsung_aes_variant *)match->data;
 	}
-	return (struct samsung_aes_variant *)
+	return (const struct samsung_aes_variant *)
 			platform_get_device_id(pdev)->driver_data;
 }
 
 static struct s5p_aes_dev *s5p_dev;
 
-static void s5p_set_dma_indata(struct s5p_aes_dev *dev, struct scatterlist *sg)
+static void s5p_set_dma_indata(struct s5p_aes_dev *dev,
+			       const struct scatterlist *sg)
 {
 	SSS_WRITE(dev, FCBRDMAS, sg_dma_address(sg));
 	SSS_WRITE(dev, FCBRDMAL, sg_dma_len(sg));
 }
 
-static void s5p_set_dma_outdata(struct s5p_aes_dev *dev, struct scatterlist *sg)
+static void s5p_set_dma_outdata(struct s5p_aes_dev *dev,
+				const struct scatterlist *sg)
 {
 	SSS_WRITE(dev, FCBTDMAS, sg_dma_address(sg));
 	SSS_WRITE(dev, FCBTDMAL, sg_dma_len(sg));
@@ -619,7 +621,7 @@ static inline void s5p_hash_write(struct s5p_aes_dev *dd,
  * @sg:		scatterlist ready to DMA transmit
  */
 static void s5p_set_dma_hashdata(struct s5p_aes_dev *dev,
-				 struct scatterlist *sg)
+				 const struct scatterlist *sg)
 {
 	dev->hash_sg_cnt--;
 	SSS_WRITE(dev, FCHRDMAS, sg_dma_address(sg));
@@ -792,9 +794,9 @@ static void s5p_hash_read_msg(struct ahash_request *req)
  * @ctx:	request context
  */
 static void s5p_hash_write_ctx_iv(struct s5p_aes_dev *dd,
-				  struct s5p_hash_reqctx *ctx)
+				  const struct s5p_hash_reqctx *ctx)
 {
-	u32 *hash = (u32 *)ctx->digest;
+	const u32 *hash = (const u32 *)ctx->digest;
 	unsigned int i;
 
 	for (i = 0; i < ctx->nregs; i++)
@@ -818,7 +820,7 @@ static void s5p_hash_write_iv(struct ahash_request *req)
  */
 static void s5p_hash_copy_result(struct ahash_request *req)
 {
-	struct s5p_hash_reqctx *ctx = ahash_request_ctx(req);
+	const struct s5p_hash_reqctx *ctx = ahash_request_ctx(req);
 
 	if (!req->result)
 		return;
@@ -1290,7 +1292,7 @@ static int s5p_hash_prepare_request(struct ahash_request *req, bool update)
  */
 static void s5p_hash_update_dma_stop(struct s5p_aes_dev *dd)
 {
-	struct s5p_hash_reqctx *ctx = ahash_request_ctx(dd->hash_req);
+	const struct s5p_hash_reqctx *ctx = ahash_request_ctx(dd->hash_req);
 
 	dma_unmap_sg(dd->dev, ctx->sg, ctx->sg_len, DMA_TO_DEVICE);
 	clear_bit(HASH_FLAGS_DMA_ACTIVE, &dd->hash_flags);
@@ -1717,7 +1719,7 @@ static void s5p_hash_cra_exit(struct crypto_tfm *tfm)
  */
 static int s5p_hash_export(struct ahash_request *req, void *out)
 {
-	struct s5p_hash_reqctx *ctx = ahash_request_ctx(req);
+	const struct s5p_hash_reqctx *ctx = ahash_request_ctx(req);
 
 	memcpy(out, ctx, sizeof(*ctx) + ctx->bufcnt);
 
@@ -1831,7 +1833,8 @@ static struct ahash_alg algs_sha1_md5_sha256[] = {
 };
 
 static void s5p_set_aes(struct s5p_aes_dev *dev,
-			uint8_t *key, uint8_t *iv, unsigned int keylen)
+			const uint8_t *key, const uint8_t *iv,
+			unsigned int keylen)
 {
 	void __iomem *keystart;
 
@@ -2150,7 +2153,7 @@ static int s5p_aes_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	int i, j, err = -ENODEV;
-	struct samsung_aes_variant *variant;
+	const struct samsung_aes_variant *variant;
 	struct s5p_aes_dev *pdata;
 	struct resource *res;
 	unsigned int hash_i;
-- 
2.7.4