f686bcb807
There are several ways a qc can get schedule for EH in new EH. This patch implements one of them - completing a qc with ATA_QCFLAG_FAILED set or with non-zero qc->err_mask. ALL such qc's are examined by EH. New EH schedules a qc for EH from completion iff ->error_handler is implemented, qc is marked as failed or qc->err_mask is non-zero and the command is not an internal command (internal cmd is handled via ->post_internal_cmd). The EH scheduling itself is performed by asking SCSI midlayer to schedule EH for the specified scmd. For drivers implementing old-EH, nothing changes. As this change makes ata_qc_complete() rather large, it's not inlined anymore and __ata_qc_complete() is exported to other parts of libata for later use. Signed-off-by: Tejun Heo <htejun@gmail.com>
291 lines
7.6 KiB
C
291 lines
7.6 KiB
C
/*
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* libata-eh.c - libata error handling
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*
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* Maintained by: Jeff Garzik <jgarzik@pobox.com>
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* Please ALWAYS copy linux-ide@vger.kernel.org
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* on emails.
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*
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* Copyright 2006 Tejun Heo <htejun@gmail.com>
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
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* USA.
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*
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*
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* libata documentation is available via 'make {ps|pdf}docs',
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* as Documentation/DocBook/libata.*
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*
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* Hardware documentation available from http://www.t13.org/ and
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* http://www.sata-io.org/
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*
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*/
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#include <linux/config.h>
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#include <linux/kernel.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_host.h>
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#include <scsi/scsi_eh.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_cmnd.h>
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#include <linux/libata.h>
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#include "libata.h"
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/**
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* ata_scsi_timed_out - SCSI layer time out callback
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* @cmd: timed out SCSI command
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*
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* Handles SCSI layer timeout. We race with normal completion of
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* the qc for @cmd. If the qc is already gone, we lose and let
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* the scsi command finish (EH_HANDLED). Otherwise, the qc has
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* timed out and EH should be invoked. Prevent ata_qc_complete()
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* from finishing it by setting EH_SCHEDULED and return
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* EH_NOT_HANDLED.
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*
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* LOCKING:
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* Called from timer context
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*
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* RETURNS:
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* EH_HANDLED or EH_NOT_HANDLED
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*/
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enum scsi_eh_timer_return ata_scsi_timed_out(struct scsi_cmnd *cmd)
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{
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struct Scsi_Host *host = cmd->device->host;
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struct ata_port *ap = ata_shost_to_port(host);
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unsigned long flags;
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struct ata_queued_cmd *qc;
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enum scsi_eh_timer_return ret = EH_HANDLED;
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DPRINTK("ENTER\n");
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spin_lock_irqsave(&ap->host_set->lock, flags);
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qc = ata_qc_from_tag(ap, ap->active_tag);
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if (qc) {
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WARN_ON(qc->scsicmd != cmd);
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qc->flags |= ATA_QCFLAG_EH_SCHEDULED;
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qc->err_mask |= AC_ERR_TIMEOUT;
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ret = EH_NOT_HANDLED;
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}
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spin_unlock_irqrestore(&ap->host_set->lock, flags);
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DPRINTK("EXIT, ret=%d\n", ret);
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return ret;
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}
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/**
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* ata_scsi_error - SCSI layer error handler callback
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* @host: SCSI host on which error occurred
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*
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* Handles SCSI-layer-thrown error events.
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*
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* LOCKING:
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* Inherited from SCSI layer (none, can sleep)
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*
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* RETURNS:
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* Zero.
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*/
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void ata_scsi_error(struct Scsi_Host *host)
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{
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struct ata_port *ap = ata_shost_to_port(host);
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DPRINTK("ENTER\n");
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/* synchronize with IRQ handler and port task */
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spin_unlock_wait(&ap->host_set->lock);
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ata_port_flush_task(ap);
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WARN_ON(ata_qc_from_tag(ap, ap->active_tag) == NULL);
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ap->ops->eng_timeout(ap);
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WARN_ON(host->host_failed || !list_empty(&host->eh_cmd_q));
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scsi_eh_flush_done_q(&ap->eh_done_q);
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DPRINTK("EXIT\n");
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}
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/**
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* ata_qc_timeout - Handle timeout of queued command
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* @qc: Command that timed out
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*
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* Some part of the kernel (currently, only the SCSI layer)
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* has noticed that the active command on port @ap has not
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* completed after a specified length of time. Handle this
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* condition by disabling DMA (if necessary) and completing
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* transactions, with error if necessary.
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*
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* This also handles the case of the "lost interrupt", where
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* for some reason (possibly hardware bug, possibly driver bug)
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* an interrupt was not delivered to the driver, even though the
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* transaction completed successfully.
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*
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* LOCKING:
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* Inherited from SCSI layer (none, can sleep)
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*/
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static void ata_qc_timeout(struct ata_queued_cmd *qc)
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{
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struct ata_port *ap = qc->ap;
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struct ata_host_set *host_set = ap->host_set;
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u8 host_stat = 0, drv_stat;
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unsigned long flags;
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DPRINTK("ENTER\n");
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ap->hsm_task_state = HSM_ST_IDLE;
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spin_lock_irqsave(&host_set->lock, flags);
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switch (qc->tf.protocol) {
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case ATA_PROT_DMA:
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case ATA_PROT_ATAPI_DMA:
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host_stat = ap->ops->bmdma_status(ap);
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/* before we do anything else, clear DMA-Start bit */
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ap->ops->bmdma_stop(qc);
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/* fall through */
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default:
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ata_altstatus(ap);
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drv_stat = ata_chk_status(ap);
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/* ack bmdma irq events */
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ap->ops->irq_clear(ap);
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ata_dev_printk(qc->dev, KERN_ERR, "command 0x%x timeout, "
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"stat 0x%x host_stat 0x%x\n",
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qc->tf.command, drv_stat, host_stat);
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/* complete taskfile transaction */
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qc->err_mask |= ac_err_mask(drv_stat);
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break;
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}
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spin_unlock_irqrestore(&host_set->lock, flags);
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ata_eh_qc_complete(qc);
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DPRINTK("EXIT\n");
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}
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/**
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* ata_eng_timeout - Handle timeout of queued command
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* @ap: Port on which timed-out command is active
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*
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* Some part of the kernel (currently, only the SCSI layer)
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* has noticed that the active command on port @ap has not
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* completed after a specified length of time. Handle this
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* condition by disabling DMA (if necessary) and completing
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* transactions, with error if necessary.
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*
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* This also handles the case of the "lost interrupt", where
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* for some reason (possibly hardware bug, possibly driver bug)
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* an interrupt was not delivered to the driver, even though the
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* transaction completed successfully.
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*
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* LOCKING:
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* Inherited from SCSI layer (none, can sleep)
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*/
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void ata_eng_timeout(struct ata_port *ap)
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{
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DPRINTK("ENTER\n");
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ata_qc_timeout(ata_qc_from_tag(ap, ap->active_tag));
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DPRINTK("EXIT\n");
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}
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/**
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* ata_qc_schedule_eh - schedule qc for error handling
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* @qc: command to schedule error handling for
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*
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* Schedule error handling for @qc. EH will kick in as soon as
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* other commands are drained.
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*
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* LOCKING:
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* spin_lock_irqsave(host_set lock)
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*/
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void ata_qc_schedule_eh(struct ata_queued_cmd *qc)
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{
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struct ata_port *ap = qc->ap;
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WARN_ON(!ap->ops->error_handler);
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qc->flags |= ATA_QCFLAG_FAILED;
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qc->ap->flags |= ATA_FLAG_EH_PENDING;
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/* The following will fail if timeout has already expired.
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* ata_scsi_error() takes care of such scmds on EH entry.
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* Note that ATA_QCFLAG_FAILED is unconditionally set after
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* this function completes.
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*/
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scsi_req_abort_cmd(qc->scsicmd);
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}
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static void ata_eh_scsidone(struct scsi_cmnd *scmd)
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{
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/* nada */
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}
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static void __ata_eh_qc_complete(struct ata_queued_cmd *qc)
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{
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struct ata_port *ap = qc->ap;
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struct scsi_cmnd *scmd = qc->scsicmd;
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unsigned long flags;
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spin_lock_irqsave(&ap->host_set->lock, flags);
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qc->scsidone = ata_eh_scsidone;
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__ata_qc_complete(qc);
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WARN_ON(ata_tag_valid(qc->tag));
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spin_unlock_irqrestore(&ap->host_set->lock, flags);
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scsi_eh_finish_cmd(scmd, &ap->eh_done_q);
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}
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/**
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* ata_eh_qc_complete - Complete an active ATA command from EH
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* @qc: Command to complete
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*
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* Indicate to the mid and upper layers that an ATA command has
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* completed. To be used from EH.
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*/
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void ata_eh_qc_complete(struct ata_queued_cmd *qc)
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{
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struct scsi_cmnd *scmd = qc->scsicmd;
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scmd->retries = scmd->allowed;
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__ata_eh_qc_complete(qc);
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}
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/**
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* ata_eh_qc_retry - Tell midlayer to retry an ATA command after EH
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* @qc: Command to retry
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*
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* Indicate to the mid and upper layers that an ATA command
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* should be retried. To be used from EH.
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*
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* SCSI midlayer limits the number of retries to scmd->allowed.
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* scmd->retries is decremented for commands which get retried
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* due to unrelated failures (qc->err_mask is zero).
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*/
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void ata_eh_qc_retry(struct ata_queued_cmd *qc)
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{
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struct scsi_cmnd *scmd = qc->scsicmd;
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if (!qc->err_mask && scmd->retries)
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scmd->retries--;
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__ata_eh_qc_complete(qc);
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}
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