From: Sebastian Siewior Subject: Re: [1/1 take 2] HIFN: preliminary HIFN 795x driver for new async cryptoapi. Date: Fri, 22 Jun 2007 14:29:48 +0200 Message-ID: <20070622122948.GA28000@Chamillionaire.breakpoint.cc> References: <20070604134248.GA9645@2ka.mipt.ru> <20070622072844.GA27341@gondor.apana.org.au> <20070622115726.GA29425@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Cc: Herbert Xu , linux-crypto@vger.kernel.org To: Evgeniy Polyakov Return-path: Received: from Chamillionaire.breakpoint.cc ([85.10.199.196]:34417 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751987AbXFVM3x (ORCPT ); Fri, 22 Jun 2007 08:29:53 -0400 Content-Disposition: inline In-Reply-To: <20070622115726.GA29425@2ka.mipt.ru> Sender: linux-crypto-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org * Evgeniy Polyakov | 2007-06-22 15:57:26 [+0400]: >On Fri, Jun 22, 2007 at 03:28:44PM +0800, Herbert Xu (herbert@gondor.apana.org.au) wrote: >> > + * Actually I need to think about how to handle the case, when queue is full. >> > + * So far error (-EINVAL) is returned. >> > + */ >> >> OK you need to provide a software queue here. Since you already >> have a hardware queue, you may choose to have a queue with a >> (advisory) maximum length of zero. However, a queue is still >> necessary since requests with the MAY_BACKLOG flag must never >> be discarded. >> >> This is (or will be) used by users such as dm-crypt that must be >> able to add at least one request but can throttle themselves >> afterwards . > >What will prevent crypto user from filling that queue with crypto >requests more and more when hardware is not capable to work with such >rate? Nothing, the hw signalizes with -EBUSY such a state and the crypto user has to slow down. If the crypto user continues such a behavior, the system will go OOM (this is atleast my understanding). >-- > Evgeniy Polyakov Sebastian