Re: [PATCH 01/10] crypto: aead - allow to allocate AEAD requests on the stack

From: 'Antoine Tenart'
Date: Sat May 05 2018 - 13:17:59 EST


Hi Herbert,

On Sat, May 05, 2018 at 02:18:55PM +0800, Herbert Xu wrote:
> On Fri, May 04, 2018 at 09:18:41AM +0200, 'Antoine Tenart' wrote:
> >
> > In this driver we need to perform in certain cases an invalidation,
> > which is done thanks to invalidation requests. To do this we create
> > dummy requests, using SKCIPHER_REQUEST_ON_STACK and
> > AHASH_REQUEST_ON_STACK for ciphers and hashes. So when adding the AEAD
> > algs support, in patch 8/10, AEAD_REQUEST_ON_STACK is used for the same
> > reason.
> >
> > Should we allocate this in a different way?
>
> These are not uses intended for the ON_STACK macros. They were
> only ever meant for existing users of the synchonous crypto API.

OK, I see.

> I would suggest either allocating a new request on the spot or if
> that is not convenient, pre-allocating it in the cra_init function.

Or we could have similar macros in the driver: we wouldn't have VLAs
since it would be driver specific.

Thanks!
Antoine

--
Antoine Ténart, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com