Re: [RFC PATCH 0/4] crypto: add CRYPTO_TFM_REQ_DMA flag
From: Iuliana Prodan
Date: Wed Nov 25 2020 - 16:39:32 EST
On 11/25/2020 11:16 PM, Ard Biesheuvel wrote:
On Wed, 25 Nov 2020 at 22:14, Iuliana Prodan (OSS)
<iuliana.prodan@xxxxxxxxxxx> wrote:
From: Iuliana Prodan <iuliana.prodan@xxxxxxx>
Add the option to allocate the crypto request object plus any extra space
needed by the driver into a DMA-able memory.
Add CRYPTO_TFM_REQ_DMA flag to be used by backend implementations to
indicate to crypto API the need to allocate GFP_DMA memory
for private contexts of the crypto requests.
These are always directional DMA mappings, right? So why can't we use
bounce buffering here?
The idea was to avoid allocating any memory in crypto drivers.
We want to be able to use dm-crypt with CAAM, which needs DMA-able
memory and increasing reqsize is not enough.
It started from here
https://lore.kernel.org/linux-crypto/71b6f739-d4a8-8b26-bf78-ce9acf9a0f99@xxxxxxx/T/#m39684173a2f0f4b83d8bcbec223e98169273d1e4
For IPsec use cases, CRYPTO_TFM_REQ_DMA flag is also checked in
esp_alloc_tmp() function for IPv4 and IPv6.
This series includes an example of how a driver can use
CRYPTO_TFM_REQ_DMA flag while setting reqsize to a larger value
to avoid allocating memory at crypto request runtime.
The extra size needed by the driver is added to the reqsize field
that indicates how much memory could be needed per request.
Iuliana Prodan (4):
crypto: add CRYPTO_TFM_REQ_DMA flag
net: esp: check CRYPTO_TFM_REQ_DMA flag when allocating crypto request
crypto: caam - avoid allocating memory at crypto request runtime for
skcipher
crypto: caam - avoid allocating memory at crypto request runtime for
aead
drivers/crypto/caam/caamalg.c | 130 +++++++++++++++++++++++++---------
include/crypto/aead.h | 4 ++
include/crypto/akcipher.h | 21 ++++++
include/crypto/hash.h | 4 ++
include/crypto/skcipher.h | 4 ++
include/linux/crypto.h | 1 +
net/ipv4/esp4.c | 7 +-
net/ipv6/esp6.c | 7 +-
8 files changed, 144 insertions(+), 34 deletions(-)
--
2.17.1