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[0/3] crypto: adjust meaning of CRYPTO_ALG_ALLOCATES_MEMORY

Message ID 20230705164009.58351-1-giovanni.cabiddu@intel.com
Headers show
Series crypto: adjust meaning of CRYPTO_ALG_ALLOCATES_MEMORY | expand

Message

Giovanni Cabiddu July 5, 2023, 4:40 p.m. UTC 
Commit fbb6cda44190 introduced the flag CRYPTO_ALG_ALLOCATES_MEMORY.
This allows to mark algorithms that allocate memory during the datapath
so they are not used for disk encryption.
Following that, cd74693870fb limited dm-crypt to use only
implementations that don't set that flag.

After discussions in the crypto mailing list [1][2][3] about how we
could re-enable algorithms to be used by dm-crypt, we came to the
conclusion that we can change slightly the meaning of the flag
!CRYPTO_ALG_ALLOCATES_MEMORY. If an algorithm does not allocate
memory for requests with a scatterlist of 4 or less entries
(the typical case for dm-crypt), then it can avoid marking the
implementation with the flag CRYPTO_ALG_ALLOCATES_MEMORY.

This set adjusts the meaning of CRYPTO_ALG_ALLOCATES_MEMORY in the
documentation, removes the filtering for algorithms that do not
allocate memory in dm-integrity and removes the
CRYPTO_ALG_ALLOCATES_MEMORY from the algorithms registered in the QAT
driver as this is not allocating memory in the datapath for requests
with 4 or less entries in the source and destination scatterlists.

[1] https://lore.kernel.org/linux-crypto/20200722072932.GA27544@gondor.apana.org.au/
[2] https://lore.kernel.org/linux-crypto/20230523165503.GA864814@google.com/
[3] https://lore.kernel.org/linux-crypto/Ysw9E2Az2oK4jfCf@lucas-Virtual-Machine/

Giovanni Cabiddu (3):
  dm integrity: do not filter algos with CRYPTO_ALG_ALLOCATES_MEMORY
  crypto: api - adjust meaning of CRYPTO_ALG_ALLOCATES_MEMORY
  crypto: qat - remove CRYPTO_ALG_ALLOCATES_MEMORY flag

 drivers/crypto/intel/qat/qat_common/qat_algs.c | 13 ++++++-------
 .../intel/qat/qat_common/qat_comp_algs.c       |  2 +-
 drivers/md/dm-integrity.c                      |  2 +-
 include/linux/crypto.h                         | 18 ++++++++++++++++--
 4 files changed, 24 insertions(+), 11 deletions(-)