Re: [PATCH 16/18] crypto: talitos - do hw_context DMA mapping outside the requests

[Christophe LEROY]

Le 07/02/2018 Ã 15:39, Horia GeantÄ a ÃcritÂ:
> On 10/6/2017 4:06 PM, Christophe Leroy wrote:
> > At every request, we map and unmap the same hash hw_context.
> >
> > This patch moves the dma mapping/unmapping in functions ahash_init()
> > and ahash_import().
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> > ---
> >   drivers/crypto/talitos.c | 80 ++++++++++++++++++++++++++++++++++--------------
> >   1 file changed, 57 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c
> > index ebfd6d982ed6..d495649d5267 100644
> > --- a/drivers/crypto/talitos.c
> > +++ b/drivers/crypto/talitos.c
> > @@ -819,6 +819,7 @@ struct talitos_ctx {
> >   	unsigned int keylen;
> >   	unsigned int enckeylen;
> >   	unsigned int authkeylen;
> > +	dma_addr_t dma_hw_context;
> This doesn't look correct.
>
> talitos_ctx structure is the tfm context.
> dma_hw_context is the IOVA of hw_context, located in talitos_ahash_req_ctx
> structure (request context).

Yes but I have now found how I can know that the request context is 
being released in order to unmap() dma at that time.
It is tricky to use the tmf context I agree, but at least I know when 
tmf context get destroyed, ie in talitos_cra_exit_ahash()
The request context is created by ahash_request_alloc() and released by
ahash_request_free(). I have not found the way to call dma_unmap() 
before ahash_request_free() gets called.

> If there are multiple requests in flight for the same tfm, dma_hw_context will
> be overwritten.

Before overwritting dma_hw_context, it is always released, see 
talitos_cra_exit_ahash(), ahash_init(), ahash_import()

> dma_hw_context needs to be moved in request context (talitos_ahash_req_ctx struct).

Any suggestion then on how to handle the issue explained above ?

Thanks
Christophe

> Thanks,
> Horia