[PATCH 2/4] net: esp: check CRYPTO_TFM_REQ_DMA flag when allocating crypto request

[PATCH 2/4] net: esp: check CRYPTO_TFM_REQ_DMA flag when allocating crypto request

[Horia Geanta]

Some crypto backends might require the requests' private contexts
to be allocated in DMA-able memory.

Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
---

Depends on patch 1/4 (sent only on crypto list) that adds the
CRYPTO_TFM_REQ_DMA flag.

 net/ipv4/esp4.c | 7 ++++++-
 net/ipv6/esp6.c | 7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 60173d4d3a0e..3e6ddece0cbe 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -38,6 +38,7 @@ static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
 {
 	unsigned int len;
+	gfp_t gfp = GFP_ATOMIC;
 
 	len = seqhilen;
 
@@ -54,7 +55,11 @@ static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
 
 	len += sizeof(struct scatterlist) * nfrags;
 
-	return kmalloc(len, GFP_ATOMIC);
+	if (crypto_aead_reqsize(aead) &&
+	    (crypto_aead_get_flags(aead) & CRYPTO_TFM_REQ_DMA))
+		gfp |= GFP_DMA;
+
+	return kmalloc(len, gfp);
 }
 
 static inline __be32 *esp_tmp_seqhi(void *tmp)
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index e48f2c7c5c59..0d173eedad4e 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -65,6 +65,7 @@ static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
 {
 	unsigned int len;
+	gfp_t gfp = GFP_ATOMIC;
 
 	len = seqihlen;
 
@@ -81,7 +82,11 @@ static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
 
 	len += sizeof(struct scatterlist) * nfrags;
 
-	return kmalloc(len, GFP_ATOMIC);
+	if (crypto_aead_reqsize(aead) &&
+	    (crypto_aead_get_flags(aead) & CRYPTO_TFM_REQ_DMA))
+		gfp |= GFP_DMA;
+
+	return kmalloc(len, gfp);
 }
 
 static inline __be32 *esp_tmp_seqhi(void *tmp)
-- 
1.8.3.1

Re: [PATCH 2/4] net: esp: check CRYPTO_TFM_REQ_DMA flag when allocating crypto request

[David Miller]

From: Horia Geanta <horia.geanta@freescale.com>
Date: Fri, 13 Mar 2015 19:15:22 +0200

> Some crypto backends might require the requests' private contexts
> to be allocated in DMA-able memory.
> 
> Signed-off-by: Horia Geanta <horia.geanta@freescale.com>

No way.

Upper layers should be absolutely not required to know about such
requirements.

Such details _must_ be hidden inside of the crypto layer and drivers
and not leak out into the users of the crypto interfaces.

Re: [PATCH 2/4] net: esp: check CRYPTO_TFM_REQ_DMA flag when allocating crypto request

[Horia Geantă]

On 3/13/2015 9:46 PM, David Miller wrote:
> From: Horia Geanta <horia.geanta@freescale.com>
> Date: Fri, 13 Mar 2015 19:15:22 +0200
> 
>> Some crypto backends might require the requests' private contexts
>> to be allocated in DMA-able memory.
>>
>> Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
> 
> No way.
> 
> Upper layers should be absolutely not required to know about such
> requirements.
> 
> Such details _must_ be hidden inside of the crypto layer and drivers
> and not leak out into the users of the crypto interfaces.

If you look at patch 1/4:
http://www.mail-archive.com/linux-crypto@vger.kernel.org/msg13428.html
that's what's done for {aead,ablkcipher,ahash}_request_alloc().

Thus users (upper layers) that allocate the crypto requests using the
crypto API are unaware of the requirement.

However, ESP is not using aead_request_alloc(). This breaks the
interface and thus some crypto implementation details are not transparent.

Re: [PATCH 2/4] net: esp: check CRYPTO_TFM_REQ_DMA flag when allocating crypto request

[David Miller]

From: Horia Geantă <horia.geanta@freescale.com>
Date: Sat, 14 Mar 2015 14:16:37 +0200

> However, ESP is not using aead_request_alloc().

Then find a way to adjust it to do so.