Re: [PATCH 2/2] crypto: caam: Use common error handling code in four functions

[Horia Geantă]

On 2/14/2018 8:32 PM, SF Markus Elfring wrote:
> From: Markus Elfring 
> Date: Wed, 14 Feb 2018 19:14:49 +0100
> 
> Add jump targets so that a bit of exception handling can be better reused
> at the end of these functions.
> 
> Signed-off-by: Markus Elfring 
[snip]
> @@ -1096,6 +1092,7 @@ static int ahash_digest(struct ahash_request *req)
>   if (!ret) {
>   ret = -EINPROGRESS;
>   } else {
> +unmap_hash:
>   ahash_unmap(jrdev, edesc, req, digestsize);
>   kfree(edesc);
>   }
> 
I understand jumps are a necessary evil for dealing with shortcomings of C,
however please avoid jumping in an if/else branch.

Code could be rewritten as:

if (!ret)
return -EINPROGRESS;

unmap_hash:
ahash_unmap(jrdev, edesc, req, digestsize);
kfree(edesc);

Thanks,
Horia

[PATCH 2/2] crypto: caam: Use common error handling code in four functions

[SF Markus Elfring]

From: Markus Elfring 
Date: Wed, 14 Feb 2018 19:14:49 +0100

Add jump targets so that a bit of exception handling can be better reused
at the end of these functions.

Signed-off-by: Markus Elfring 
---
 drivers/crypto/caam/caamalg.c  | 32 
 drivers/crypto/caam/caamhash.c | 23 ++-
 2 files changed, 26 insertions(+), 29 deletions(-)

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index d1f25a90552a..3d26c44040c7 100644
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -1560,11 +1560,8 @@ static struct ablkcipher_edesc 
*ablkcipher_edesc_alloc(struct ablkcipher_request
/* allocate space for base edesc and hw desc commands, link tables */
edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes,
GFP_DMA | flags);
-   if (!edesc) {
-   caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
-  iv_dma, ivsize, 0, 0);
-   return ERR_PTR(-ENOMEM);
-   }
+   if (!edesc)
+   goto unmap_caam;
 
edesc->src_nents = src_nents;
edesc->dst_nents = dst_nents;
@@ -1587,10 +1584,8 @@ static struct ablkcipher_edesc 
*ablkcipher_edesc_alloc(struct ablkcipher_request
sec4_sg_bytes, DMA_TO_DEVICE);
if (dma_mapping_error(jrdev, edesc->sec4_sg_dma)) {
dev_err(jrdev, "unable to map S/G table\n");
-   caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
-  iv_dma, ivsize, 0, 0);
kfree(edesc);
-   return ERR_PTR(-ENOMEM);
+   goto unmap_caam;
}
 
edesc->iv_dma = iv_dma;
@@ -1603,6 +1598,11 @@ static struct ablkcipher_edesc 
*ablkcipher_edesc_alloc(struct ablkcipher_request
 
*iv_contig_out = in_contig;
return edesc;
+
+unmap_caam:
+   caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
+  iv_dma, ivsize, 0, 0);
+   return ERR_PTR(-ENOMEM);
 }
 
 static int ablkcipher_encrypt(struct ablkcipher_request *req)
@@ -1768,11 +1768,8 @@ static struct ablkcipher_edesc 
*ablkcipher_giv_edesc_alloc(
sec4_sg_bytes = sec4_sg_ents * sizeof(struct sec4_sg_entry);
edesc = kzalloc(sizeof(*edesc) + desc_bytes + sec4_sg_bytes,
GFP_DMA | flags);
-   if (!edesc) {
-   caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
-  iv_dma, ivsize, 0, 0);
-   return ERR_PTR(-ENOMEM);
-   }
+   if (!edesc)
+   goto unmap_caam;
 
edesc->src_nents = src_nents;
edesc->dst_nents = dst_nents;
@@ -1795,10 +1792,8 @@ static struct ablkcipher_edesc 
*ablkcipher_giv_edesc_alloc(
sec4_sg_bytes, DMA_TO_DEVICE);
if (dma_mapping_error(jrdev, edesc->sec4_sg_dma)) {
dev_err(jrdev, "unable to map S/G table\n");
-   caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
-  iv_dma, ivsize, 0, 0);
kfree(edesc);
-   return ERR_PTR(-ENOMEM);
+   goto unmap_caam;
}
edesc->iv_dma = iv_dma;
 
@@ -1811,6 +1806,11 @@ static struct ablkcipher_edesc 
*ablkcipher_giv_edesc_alloc(
 
*iv_contig_out = out_contig;
return edesc;
+
+unmap_caam:
+   caam_unmap(jrdev, req->src, req->dst, src_nents, dst_nents,
+  iv_dma, ivsize, 0, 0);
+   return ERR_PTR(-ENOMEM);
 }
 
 static int ablkcipher_givencrypt(struct skcipher_givcrypt_request *creq)
diff --git a/drivers/crypto/caam/caamhash.c b/drivers/crypto/caam/caamhash.c
index dc269eba08ad..b5e43a1f38f0 100644
--- a/drivers/crypto/caam/caamhash.c
+++ b/drivers/crypto/caam/caamhash.c
@@ -371,16 +371,16 @@ static int hash_digest_key(struct caam_hash_ctx *ctx, 
const u8 *key_in,
 DMA_TO_DEVICE);
if (dma_mapping_error(jrdev, src_dma)) {
dev_err(jrdev, "unable to map key input memory\n");
-   kfree(desc);
-   return -ENOMEM;
+   ret = -ENOMEM;
+   goto free_desc;
}
dst_dma = dma_map_single(jrdev, (void *)key_out, digestsize,
 DMA_FROM_DEVICE);
if (dma_mapping_error(jrdev, dst_dma)) {
dev_err(jrdev, "unable to map key output memory\n");
dma_unmap_single(jrdev, src_dma, *keylen, DMA_TO_DEVICE);
-   kfree(desc);
-   return -ENOMEM;
+   ret = -ENOMEM;
+   goto free_desc;
}
 
/* Job descriptor to perform unkeyed hash on key_in */
@@ -419,7 +419,7 @@ static int hash_digest_key(struct caam_hash_ctx *ctx, const 
u8 *key_in,
dma_unmap_single(jrdev, dst_dma, digestsize, DMA_FROM_DEVICE);
 
*keylen = digestsize;
-
+free_desc: