CRYPTO_ALG_ASYNC

Hello Herbert,

CRYPTO_ALG_ASYNC is heavily used like:

    crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
or
   .cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC;
   .cra_flags = CRYPTO_ALG_TYPE_AHASH |  CRYPTO_ALG_ASYNC,

I see that only place where it is tested is in
ablockcipher.c:crypto_default_geniv()

What is actually meaning of that?

and setting it for hash??

Thanks,
Dmitry