From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH #upstream 1/2] libata: move command post processing to __ata_qc_complete() Date: Wed, 17 Oct 2007 21:23:05 -0400 Message-ID: <4716B579.7070005@garzik.org> References: <20071012115631.GA11510@htj.dyndns.org> <470F64D7.9040604@garzik.org> <4710C39E.7060503@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:43047 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761598AbXJRBXH (ORCPT ); Wed, 17 Oct 2007 21:23:07 -0400 In-Reply-To: <4710C39E.7060503@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: linux-ide@vger.kernel.org, ballen@gravity.phys.uwm.edu, andrew@ishiboo.com Tejun Heo wrote: > Jeff Garzik wrote: >> Tejun Heo wrote: >>> Some commands need post-processing after successful completion. This >>> was done in ata_scsi_qc_complete() till now but command post >>> processing doesn't belong to SAT layer. Move them to >>> __ata_qc_complete() and, while at it, restructure a bit to ease adding >>> post-processing for other commands. >>> >>> Signed-off-by: Tejun Heo >> BTW, while doing the TEST UNIT READY emulation patch for ATA (recently >> withdrawn from libata-dev.git#upstream), I found a problem with the >> interface that was difficult to get around: TEST UNIT READY simulation >> code really wants to look at the result TF of CHECK POWER MODE, even if >> ATA_ERR is asserted, before determining whether or not to call that >> command an error. >> >> Maybe the EH scheduling could be moved until after ->complete_fn, to >> permit ->complete_fn users to manipulate qc->err_mask etc.? > > Yeah, right. Device error is a special case. In many cases, devices > can operate without any problem after asserting error and for some > commands error is used to signal certain conditions. I think the least > intrusive way would be a qc flag - ATA_QCFLAG_ALLOW_DEVERR, maybe. > Also, I'm not sure whether EH should kick in when passthru commands fail > with a device error. Maybe libata should just report the error to the > issuer and continue operation? Good point and agreed -- I definitely think passthru commands want device errors immediately. That vastly increases the utility of passthru to be used in test suites and stuff, where you know a lot of operations should fail, by design. (i.e. intentionally submitting an invalid command, to test that 'command aborted' is returned) Jeff