On Tue, 2017-07-25 at 00:53 +0000, Dey, Megha wrote:
> 
> -----Original Message-----
> From: Herbert Xu [mailto:[email protected]] 
> Sent: Wednesday, July 19, 2017 12:02 AM
> To: Dey, Megha <[email protected]>
> Cc: Tim Chen <[email protected]>; [email protected]; 
> [email protected]; [email protected]
> Subject: Re: [PATCH V6 5/7] crypto: AES CBC multi-buffer glue code
> 
> On Tue, Jul 18, 2017 at 06:18:59PM -0700, Megha Dey wrote:
> >
> > > >> +/*
> > > >> + * CRYPTO_ALG_ASYNC flag is passed to indicate we have an ablk
> > > >> + * scatter-gather walk.
> > > >> + */
> > > >> +static struct skcipher_alg aes_cbc_mb_alg = {
> > > >> +      .base = {
> > > >> +              .cra_name               = "cbc(aes)",
> > > >> +              .cra_driver_name        = "cbc-aes-aesni-mb",
> > > >> +              .cra_priority           = 500,
> > > >> +              .cra_flags              = CRYPTO_ALG_INTERNAL,
> > > >> +              .cra_blocksize          = AES_BLOCK_SIZE,
> > > >> +              .cra_ctxsize            = CRYPTO_AES_CTX_SIZE,
> > > >> +              .cra_module             = THIS_MODULE,
> > > >> +      },
> > > >> +      .min_keysize    = AES_MIN_KEY_SIZE,
> > > >> +      .max_keysize    = AES_MAX_KEY_SIZE,
> > > >> +      .ivsize         = AES_BLOCK_SIZE,
> > > >> +      .setkey         = aes_set_key,
> > > >> +      .encrypt        = mb_aes_cbc_encrypt,
> > > >> +      .decrypt        = mb_aes_cbc_decrypt
> > > >> +};
> > > > 
> > > > So this claims to be a sync algorithm.  Is this really the case?
> > 
> > yes, the inner algorithm is sync whereas the outer algorithm is async.
> 
> Are you saying that once mb_aes_cbc_encrypt returns it will never touch the 
> input/output again? This doesn't seem to agree with the actual code:
> 
> +       if (!ret_rctx) {
> +               /* we submitted a job, but none completed */
> +               /* just notify the caller */
> +               notify_callback(rctx, cstate, -EINPROGRESS);
> +               return 0;
> +       }
> 
> Just because an algorithm is internal doesn't mean that it can arbitrarily 
> violate the crypto API requirements.
> 
> Cheers,

Hi Herbert,

Under the skcipher interface, if both the outer and inner alg are async,
there should not be any problem right? Currently I do not see any
existing algorithms have both algorithms async.
> --
> Email: Herbert Xu <[email protected]> Home Page: 
> http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt


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