From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ilya Yanok Subject: Re: [PATCH 06/13] async_tx: add support for asynchronous GF multiplication Date: Sat, 21 Mar 2009 02:00:42 +0300 Message-ID: <49C4201A.5060905@emcraft.com> References: <20090318191248.20375.40560.stgit@dwillia2-linux.ch.intel.com> <20090318192046.20375.89854.stgit@dwillia2-linux.ch.intel.com> <49C26D91.10804@intel.com> <49C41C1E.4060401@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <49C41C1E.4060401@zytor.com> Sender: linux-kernel-owner@vger.kernel.org To: "H. Peter Anvin" Cc: Dan Williams , "H. Peter Anvin" , linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, neilb@suse.de, maciej.sosnowski@intel.com, Yuri Tikhonov List-Id: linux-raid.ids Hi H. Peter, H. Peter Anvin wrote: >> Something is broken if we take this path. This routine could stand to >> have a WARN_ONCE(), because if it is ever called there is something is >> wrong with the raid6 offload driver. The intent is that the >> asynchronous recovery routines will perform an early check to see if >> the recovery can be offloaded (with a series of calls to >> async_xor/async_pq). If not we fall back to the optimized synchronous >> recovery routines (raid6_2data_recov, raid6_datap_recov). The only >> time this path will be taken is if we have decided to perform >> asynchronous recovery but at a later call to async_pq the offload >> driver reports it has run out of descriptors. >> > > That doesn't explain what you expect the code to do. It still doesn't > make sense to me. We defined async_pq() function as hardware can do GF multiplication of arbitrary elements and we want to take advantage of this fact. But by the design of ASYNC_TX API we have to provide synchronous version of that function too. Regards, Ilya.