From: Evgeniy Polyakov Subject: Re: hifn_795x in Linux-2.6.27-rc7 Date: Wed, 24 Sep 2008 06:53:08 +0400 Message-ID: <20080924025308.GA27398@2ka.mipt.ru> References: <20080923165521.GA26513@2ka.mipt.ru> <48D93028.20903@psycast.de> <20080923181840.GA24982@2ka.mipt.ru> <20080923.145515.34843004.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: max@psycast.de, linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au To: David Miller Return-path: Received: from relay.2ka.mipt.ru ([194.85.80.65]:35223 "EHLO 2ka.mipt.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751205AbYIXCyI (ORCPT ); Tue, 23 Sep 2008 22:54:08 -0400 Content-Disposition: inline In-Reply-To: <20080923.145515.34843004.davem@davemloft.net> Sender: linux-crypto-owner@vger.kernel.org List-ID: On Tue, Sep 23, 2008 at 02:55:15PM -0700, David Miller (davem@davemloft.net) wrote: > > Yes, I was wrong with the patch: HIFN does not support 64-bit addresses > > afaics. > > > > Attached patch should not allow HIFN to be registered on 64-bit arch, so > > crypto layer will fallback to the software algorithms. > > > > Signed-off-by: Evgeniy Polyakov > > Well, it will disallow HIFN on 32-bit systems using highmem too. :-) Yes, but only 64g, where dma_addr_t is 8 bytes. > In the end, you will need to use bouncebuffers or similar, it seems. Maybe, we need to check, since allocation of multiple smaller pages from 4 gb area, copy data between them, hardware crypto, backward copy and page freeing can be slower than software crypto. Although we can preallocate buffers for several common sizes, although this will not help dm-crypto which can submit up to 31 pages in single request on top of ext3 in the common case. -- Evgeniy Polyakov