linux/Documentation/crypto
Eric Biggers 877b5691f2 crypto: shash - remove shash_desc::flags
The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.

With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP.  These would all need to be fixed if any shash algorithm
actually started sleeping.  For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API.  However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.

Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk.  It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.

Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-04-25 15:38:12 +08:00
..
api-aead.rst
api-akcipher.rst
api-digest.rst
api-intro.txt
api-kpp.rst
api-rng.rst
api-samples.rst crypto: shash - remove shash_desc::flags 2019-04-25 15:38:12 +08:00
api-skcipher.rst
api.rst crypto: skcipher - remove remnants of internal IV generators 2018-12-23 11:52:45 +08:00
architecture.rst crypto: skcipher - remove remnants of internal IV generators 2018-12-23 11:52:45 +08:00
asymmetric-keys.txt KEYS: Implement PKCS#8 RSA Private Key parser [ver #2] 2018-10-26 09:30:46 +01:00
async-tx-api.txt
conf.py
crypto_engine.rst docs: crypto_engine.rst: Fix two parse warnings 2018-06-15 12:48:59 -03:00
descore-readme.txt
devel-algos.rst crypto: doc - clarify hash callbacks state machine 2018-03-31 01:33:02 +08:00
index.rst docs: */index.rst: Add newer documents to their respective index.rst 2018-05-08 09:57:35 -06:00
intro.rst
userspace-if.rst crypto: doc - fix typo in docs 2017-06-22 16:54:07 +08:00