On Thu, 5 Mar 2015 11:35:23 +0200 Horia Geantă <horia.geanta@xxxxxxxxxxxxx> wrote: > On 3/4/2015 2:23 AM, Kim Phillips wrote: > > On Tue, 3 Mar 2015 08:21:37 -0500 > > Martin Hicks <mort@xxxxxxxx> wrote: > > > >> @@ -1170,6 +1237,8 @@ static struct talitos_edesc *talitos_edesc_alloc(struct device *dev, > >> edesc->dma_len, > >> DMA_BIDIRECTIONAL); > >> edesc->req.desc = &edesc->desc; > >> + /* A copy of the crypto_async_request to use the crypto_queue backlog */ > >> + memcpy(&edesc->req.base, areq, sizeof(struct crypto_async_request)); > > > > this seems backward, or, at least can be done more efficiently IMO: > > talitos_cra_init should set the tfm's reqsize so the rest of > > the driver can wholly embed its talitos_edesc (which should also > > wholly encapsulate its talitos_request (i.e., not via a pointer)) > > into the crypto API's request handle allocation. This > > would absorb and eliminate the talitos_edesc kmalloc and frees, the > > above memcpy, and replace the container_of after the > > crypto_dequeue_request with an offset_of, right? > > > > When scatter-gather buffers are needed, we can assume a slower-path > > and make them do their own allocations, since their sizes vary > > depending on each request. Of course, a pointer to those > > allocations would need to be retained somewhere in the request > > handle. > > Unfortunately talitos_edesc structure size is most of the times > variable. Its exact size can only be established at "request time", and > not at "tfm init time". yes, I was suggesting a common minimum should be set in cra_init. > Fixed size would be sizeof(talitos_edesc). > Below are factors that influence the variable part, i.e. link_tbl in > talitos_edesc: > - whether any assoc / src / dst data is scattered > - icv_stashing (case when ICV checking is done in SW) both being slow(er) paths, IMO. > Still we'd be better with: > -crypto API allocates request + request context (i.e. > sizeof(talitos_edesc) + any alignment required) > -talitos driver allocates variable part of talitos_edesc (if needed) > > instead of: > -crypto API allocates request > -talitos driver allocates talitos_edesc (fixed + variable) > -memcopy of the req.base (crypto_async_request) into talitos_edesc > > both in terms of performance and readability. indeed. > At first look, the driver wouldn't change that much: > -talitos_cra_init() callback would have to set tfm.reqsize to > sizeof(talitos_edesc) + padding and also add the CRYPTO_TFM_REQ_DMA > indication in tfm.crt_flags > -talitos_edesc_alloc() logic would be pretty much the same, but would > allocate memory only for the link_tbl > > I'm willing to do these changes if needed. Please coordinate with Martin. fwiw, caam could use this, too. Kim -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
