From mboxrd@z Thu Jan 1 00:00:00 1970 From: Albert Lee Subject: Re: [PATCH 08/11] libata-eh-fw: implement new EH scheduling from PIO Date: Thu, 18 May 2006 18:42:48 +0800 Message-ID: <446C4FA8.5020105@tw.ibm.com> References: <1147350444826-git-send-email-htejun@gmail.com> Reply-To: albertl@mail.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:54167 "EHLO e35.co.us.ibm.com") by vger.kernel.org with ESMTP id S1750984AbWERKmt (ORCPT ); Thu, 18 May 2006 06:42:49 -0400 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e35.co.us.ibm.com (8.12.11.20060308/8.12.11) with ESMTP id k4IAgnY0001840 for ; Thu, 18 May 2006 06:42:49 -0400 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by westrelay02.boulder.ibm.com (8.12.10/NCO/VER6.8) with ESMTP id k4IAgnRI269758 for ; Thu, 18 May 2006 04:42:49 -0600 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id k4IAgmgC029838 for ; Thu, 18 May 2006 04:42:49 -0600 In-Reply-To: <1147350444826-git-send-email-htejun@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: jgarzik@pobox.com, alan@lxorguk.ukuu.org.uk, axboe@suse.de, forrest.zhao@intel.com, efalk@google.com, linux-ide@vger.kernel.org Tejun Heo wrote: > PIO executes without holding host_set lock, so it cannot be > synchronized using the same mechanism as interrupt driven execution. > port_task framework makes sure that EH is not entered until PIO task > is flushed, so PIO task can be sure the qc in progress won't go away > underneath it. One thing it cannot be sure of is whether the qc has > already been scheduled for EH by another exception condition while > host_set lock was released. > > This patch makes ata_poll_qc-complete() handle such conditions > properly and make it freeze the port if HSM violation is detected > during PIO execution. > > Signed-off-by: Tejun Heo > > --- > > drivers/scsi/libata-core.c | 23 +++++++++++++++++++---- > 1 files changed, 19 insertions(+), 4 deletions(-) > > 52240d1d208615e461c41a5c297f521a8a892f0d > diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c > index 436ff5b..86d6a7d 100644 > --- a/drivers/scsi/libata-core.c > +++ b/drivers/scsi/libata-core.c > @@ -3429,16 +3429,31 @@ skip_map: > * LOCKING: > * None. (grabs host lock) > */ > - > void ata_poll_qc_complete(struct ata_queued_cmd *qc) > { > struct ata_port *ap = qc->ap; > unsigned long flags; > > spin_lock_irqsave(&ap->host_set->lock, flags); > - ap->flags &= ~ATA_FLAG_NOINTR; > - ata_irq_on(ap); > - ata_qc_complete(qc); > + > + if (ap->ops->error_handler) { > + /* EH might have kicked in while host_set lock is released */ > + qc = ata_qc_from_tag(ap, qc->tag); > + if (qc) { > + if (!(qc->err_mask & AC_ERR_HSM)) { > + ap->flags &= ~ATA_FLAG_NOINTR; > + ata_irq_on(ap); > + ata_qc_complete(qc); > + } else > + ata_port_freeze(ap); I don't quite understand here. For the AC_ERR_HSM error, how does the EH get triggered after ata_port_freeze()? Do we wait until time out? > + } > + } else { > + /* old EH */ > + ap->flags &= ~ATA_FLAG_NOINTR; > + ata_irq_on(ap); > + ata_qc_complete(qc); > + } > + > spin_unlock_irqrestore(&ap->host_set->lock, flags); > } >