Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754757AbZIOQHH (ORCPT ); Tue, 15 Sep 2009 12:07:07 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755012AbZIOQG7 (ORCPT ); Tue, 15 Sep 2009 12:06:59 -0400 Received: from mga03.intel.com ([143.182.124.21]:8861 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754985AbZIOQGw convert rfc822-to-8bit (ORCPT ); Tue, 15 Sep 2009 12:06:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.44,391,1249282800"; d="scan'208";a="187877783" From: "Sosnowski, Maciej" To: "Williams, Dan J" CC: "linux-kernel@vger.kernel.org" , "linux-raid@vger.kernel.org" Date: Tue, 15 Sep 2009 17:06:52 +0100 Subject: RE: [PATCH 05/18] ioat2+: add fence support Thread-Topic: [PATCH 05/18] ioat2+: add fence support Thread-Index: AcotKzvhbeIX53r3R4iqHzsP0xHv6gI80BFw Message-ID: <129600E5E5FB004392DDC3FB599660D7B554878E@irsmsx504.ger.corp.intel.com> References: <20090904064308.7141.30576.stgit@dwillia2-linux.ch.intel.com> <20090904064500.7141.60154.stgit@dwillia2-linux.ch.intel.com> In-Reply-To: <20090904064500.7141.60154.stgit@dwillia2-linux.ch.intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1032 Lines: 20 Williams, Dan J wrote: > In preparation for adding more operation types to the ioat3 path the > driver needs to honor the DMA_PREP_FENCE flag. For example the async_tx api > will hand xor->memcpy->xor chains to the driver with the 'fence' flag set on > the first xor and the memcpy operation. This flag in turn sets the 'fence' > flag in the descriptor control field telling the hardware that future > descriptors in the chain depend on the result of the current descriptor, so > wait for all writes to complete before starting the next operation. > > Note that ioat1 does not prefetch the descriptor chain, so does not > require/support fenced operations. > > Signed-off-by: Dan Williams > --- Signed-off-by: Maciej Sosnowski -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/