From: Dan Williams Subject: Re: [PATCH v2 2/2] Crypto: Talitos: Support for Async_tx XOR offload Date: Thu, 17 Dec 2009 10:44:26 -0700 Message-ID: <4B2A6DFA.6000504@intel.com> References: <1260977698-4076-1-git-send-email-Vishnu@freescale.com> <20091216164144.daff5468.kim.phillips@freescale.com> <2868C8CF-584B-4FA7-9C3B-2FACEF77527E@kernel.crashing.org> <4B296394.9010709@intel.com> <20091217170958.GE18271@ovro.caltech.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Kumar Gala , "herbert@gondor.apana.org.au" , "B04825@freescale.com" , "linux-kernel@vger.kernel.org" , "linux-raid@vger.kernel.org" , "linuxppc-dev@ozlabs.org" , Vishnu Suresh , "linux-crypto@vger.kernel.org" , Dipen Dudhat , Maneesh Gupta , "R58472@freescale.com" To: "Ira W. Snyder" Return-path: In-Reply-To: <20091217170958.GE18271@ovro.caltech.edu> Sender: linux-raid-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Ira W. Snyder wrote: > Yes, I have used the device_prep_dma_interrupt() functionality quite a > while back. However, I found it to be pretty much useless. The specific case it is needed for Talitos/raid is a channel switch interrupt. The interrupt causes the cleanup operation to be run which will kick off any pending dependent operations on the xor channel. In the raid case we only have callbacks at the end of a chain, so we need the interrupt to kick the engine in an operation chain like xor->copy->xor->callback. -- Dan