scsi_error.c 66.6 KB
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/*
 *  scsi_error.c Copyright (C) 1997 Eric Youngdale
 *
 *  SCSI error/timeout handling
 *      Initial versions: Eric Youngdale.  Based upon conversations with
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 *                        Leonard Zubkoff and David Miller at Linux Expo,
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 *                        ideas originating from all over the place.
 *
 *	Restructured scsi_unjam_host and associated functions.
 *	September 04, 2002 Mike Anderson (andmike@us.ibm.com)
 *
 *	Forward port of Russell King's (rmk@arm.linux.org.uk) changes and
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 *	minor cleanups.
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 *	September 30, 2002 Mike Anderson (andmike@us.ibm.com)
 */

#include <linux/module.h>
#include <linux/sched.h>
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#include <linux/gfp.h>
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#include <linux/timer.h>
#include <linux/string.h>
#include <linux/kernel.h>
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#include <linux/freezer.h>
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#include <linux/kthread.h>
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#include <linux/interrupt.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
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#include <linux/jiffies.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_cmnd.h>
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#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
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#include <scsi/scsi_driver.h>
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#include <scsi/scsi_eh.h>
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#include <scsi/scsi_transport.h>
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#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>

#include "scsi_priv.h"
#include "scsi_logging.h"
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#include "scsi_transport_api.h"
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#include <trace/events/scsi.h>

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static void scsi_eh_done(struct scsi_cmnd *scmd);

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/*
 * These should *probably* be handled by the host itself.
 * Since it is allowed to sleep, it probably should.
 */
#define BUS_RESET_SETTLE_TIME   (10)
#define HOST_RESET_SETTLE_TIME  (10)

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static int scsi_eh_try_stu(struct scsi_cmnd *scmd);

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/* called with shost->host_lock held */
void scsi_eh_wakeup(struct Scsi_Host *shost)
{
	if (shost->host_busy == shost->host_failed) {
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		trace_scsi_eh_wakeup(shost);
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		wake_up_process(shost->ehandler);
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		SCSI_LOG_ERROR_RECOVERY(5,
				printk("Waking error handler thread\n"));
	}
}
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/**
 * scsi_schedule_eh - schedule EH for SCSI host
 * @shost:	SCSI host to invoke error handling on.
 *
 * Schedule SCSI EH without scmd.
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 */
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void scsi_schedule_eh(struct Scsi_Host *shost)
{
	unsigned long flags;

	spin_lock_irqsave(shost->host_lock, flags);

	if (scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
	    scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0) {
		shost->host_eh_scheduled++;
		scsi_eh_wakeup(shost);
	}

	spin_unlock_irqrestore(shost->host_lock, flags);
}
EXPORT_SYMBOL_GPL(scsi_schedule_eh);
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static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
{
	if (!shost->last_reset || !shost->eh_deadline)
		return 0;

	if (time_before(jiffies,
			shost->last_reset + shost->eh_deadline))
		return 0;

	return 1;
}

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/**
 * scsi_eh_scmd_add - add scsi cmd to error handling.
 * @scmd:	scmd to run eh on.
 * @eh_flag:	optional SCSI_EH flag.
 *
 * Return value:
 *	0 on failure.
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 */
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int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
{
	struct Scsi_Host *shost = scmd->device->host;
	unsigned long flags;
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	int ret = 0;
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	if (!shost->ehandler)
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		return 0;

	spin_lock_irqsave(shost->host_lock, flags);
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	if (scsi_host_set_state(shost, SHOST_RECOVERY))
		if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
			goto out_unlock;
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	if (shost->eh_deadline && !shost->last_reset)
		shost->last_reset = jiffies;

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	ret = 1;
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	scmd->eh_eflags |= eh_flag;
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	list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
	shost->host_failed++;
	scsi_eh_wakeup(shost);
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 out_unlock:
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	spin_unlock_irqrestore(shost->host_lock, flags);
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	return ret;
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}

/**
 * scsi_times_out - Timeout function for normal scsi commands.
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 * @req:	request that is timing out.
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 *
 * Notes:
 *     We do not need to lock this.  There is the potential for a race
 *     only in that the normal completion handling might run, but if the
 *     normal completion function determines that the timer has already
 *     fired, then it mustn't do anything.
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 */
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enum blk_eh_timer_return scsi_times_out(struct request *req)
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{
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	struct scsi_cmnd *scmd = req->special;
	enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
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	struct Scsi_Host *host = scmd->device->host;
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	trace_scsi_dispatch_cmd_timeout(scmd);
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	scsi_log_completion(scmd, TIMEOUT_ERROR);

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	if (host->eh_deadline && !host->last_reset)
		host->last_reset = jiffies;

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	if (host->transportt->eh_timed_out)
		rtn = host->transportt->eh_timed_out(scmd);
	else if (host->hostt->eh_timed_out)
		rtn = host->hostt->eh_timed_out(scmd);
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	scmd->result |= DID_TIME_OUT << 16;

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	if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
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		     !scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD)))
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		rtn = BLK_EH_HANDLED;
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	return rtn;
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}

/**
 * scsi_block_when_processing_errors - Prevent cmds from being queued.
 * @sdev:	Device on which we are performing recovery.
 *
 * Description:
 *     We block until the host is out of error recovery, and then check to
 *     see whether the host or the device is offline.
 *
 * Return value:
 *     0 when dev was taken offline by error recovery. 1 OK to proceed.
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 */
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int scsi_block_when_processing_errors(struct scsi_device *sdev)
{
	int online;

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	wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
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	online = scsi_device_online(sdev);

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	SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
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					  online));

	return online;
}
EXPORT_SYMBOL(scsi_block_when_processing_errors);

#ifdef CONFIG_SCSI_LOGGING
/**
 * scsi_eh_prt_fail_stats - Log info on failures.
 * @shost:	scsi host being recovered.
 * @work_q:	Queue of scsi cmds to process.
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 */
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static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
					  struct list_head *work_q)
{
	struct scsi_cmnd *scmd;
	struct scsi_device *sdev;
	int total_failures = 0;
	int cmd_failed = 0;
	int cmd_cancel = 0;
	int devices_failed = 0;

	shost_for_each_device(sdev, shost) {
		list_for_each_entry(scmd, work_q, eh_entry) {
			if (scmd->device == sdev) {
				++total_failures;
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				if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
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					++cmd_cancel;
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				else
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					++cmd_failed;
			}
		}

		if (cmd_cancel || cmd_failed) {
			SCSI_LOG_ERROR_RECOVERY(3,
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				sdev_printk(KERN_INFO, sdev,
					    "%s: cmds failed: %d, cancel: %d\n",
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					    __func__, cmd_failed,
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					    cmd_cancel));
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			cmd_cancel = 0;
			cmd_failed = 0;
			++devices_failed;
		}
	}

	SCSI_LOG_ERROR_RECOVERY(2, printk("Total of %d commands on %d"
					  " devices require eh work\n",
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				   total_failures, devices_failed));
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}
#endif

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 /**
 * scsi_report_lun_change - Set flag on all *other* devices on the same target
 *                          to indicate that a UNIT ATTENTION is expected.
 * @sdev:	Device reporting the UNIT ATTENTION
 */
static void scsi_report_lun_change(struct scsi_device *sdev)
{
	sdev->sdev_target->expecting_lun_change = 1;
}

/**
 * scsi_report_sense - Examine scsi sense information and log messages for
 *		       certain conditions, also issue uevents for some of them.
 * @sdev:	Device reporting the sense code
 * @sshdr:	sshdr to be examined
 */
static void scsi_report_sense(struct scsi_device *sdev,
			      struct scsi_sense_hdr *sshdr)
{
	enum scsi_device_event evt_type = SDEV_EVT_MAXBITS;	/* i.e. none */

	if (sshdr->sense_key == UNIT_ATTENTION) {
		if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
			evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
			sdev_printk(KERN_WARNING, sdev,
				    "Inquiry data has changed");
		} else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
			evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
			scsi_report_lun_change(sdev);
			sdev_printk(KERN_WARNING, sdev,
				    "Warning! Received an indication that the "
				    "LUN assignments on this target have "
				    "changed. The Linux SCSI layer does not "
				    "automatically remap LUN assignments.\n");
		} else if (sshdr->asc == 0x3f)
			sdev_printk(KERN_WARNING, sdev,
				    "Warning! Received an indication that the "
				    "operating parameters on this target have "
				    "changed. The Linux SCSI layer does not "
				    "automatically adjust these parameters.\n");

		if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
			evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
			sdev_printk(KERN_WARNING, sdev,
				    "Warning! Received an indication that the "
				    "LUN reached a thin provisioning soft "
				    "threshold.\n");
		}

		if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
			evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
			sdev_printk(KERN_WARNING, sdev,
				    "Mode parameters changed");
		} else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
			evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
			sdev_printk(KERN_WARNING, sdev,
				    "Capacity data has changed");
		} else if (sshdr->asc == 0x2a)
			sdev_printk(KERN_WARNING, sdev,
				    "Parameters changed");
	}

	if (evt_type != SDEV_EVT_MAXBITS) {
		set_bit(evt_type, sdev->pending_events);
		schedule_work(&sdev->event_work);
	}
}

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/**
 * scsi_check_sense - Examine scsi cmd sense
 * @scmd:	Cmd to have sense checked.
 *
 * Return value:
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 *	SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
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 *
 * Notes:
 *	When a deferred error is detected the current command has
 *	not been executed and needs retrying.
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 */
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static int scsi_check_sense(struct scsi_cmnd *scmd)
{
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	struct scsi_device *sdev = scmd->device;
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	struct scsi_sense_hdr sshdr;

	if (! scsi_command_normalize_sense(scmd, &sshdr))
		return FAILED;	/* no valid sense data */

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	if (scmd->cmnd[0] == TEST_UNIT_READY && scmd->scsi_done != scsi_eh_done)
		/*
		 * nasty: for mid-layer issued TURs, we need to return the
		 * actual sense data without any recovery attempt.  For eh
		 * issued ones, we need to try to recover and interpret
		 */
		return SUCCESS;

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	scsi_report_sense(sdev, &sshdr);

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	if (scsi_sense_is_deferred(&sshdr))
		return NEEDS_RETRY;

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	if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
			sdev->scsi_dh_data->scsi_dh->check_sense) {
		int rc;

		rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
		if (rc != SCSI_RETURN_NOT_HANDLED)
			return rc;
		/* handler does not care. Drop down to default handling */
	}

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	/*
	 * Previous logic looked for FILEMARK, EOM or ILI which are
	 * mainly associated with tapes and returned SUCCESS.
	 */
	if (sshdr.response_code == 0x70) {
		/* fixed format */
		if (scmd->sense_buffer[2] & 0xe0)
			return SUCCESS;
	} else {
		/*
		 * descriptor format: look for "stream commands sense data
		 * descriptor" (see SSC-3). Assume single sense data
		 * descriptor. Ignore ILI from SBC-2 READ LONG and WRITE LONG.
		 */
		if ((sshdr.additional_length > 3) &&
		    (scmd->sense_buffer[8] == 0x4) &&
		    (scmd->sense_buffer[11] & 0xe0))
			return SUCCESS;
	}

	switch (sshdr.sense_key) {
	case NO_SENSE:
		return SUCCESS;
	case RECOVERED_ERROR:
		return /* soft_error */ SUCCESS;

	case ABORTED_COMMAND:
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		if (sshdr.asc == 0x10) /* DIF */
			return SUCCESS;

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		return NEEDS_RETRY;
	case NOT_READY:
	case UNIT_ATTENTION:
		/*
		 * if we are expecting a cc/ua because of a bus reset that we
		 * performed, treat this just as a retry.  otherwise this is
		 * information that we should pass up to the upper-level driver
		 * so that we can deal with it there.
		 */
		if (scmd->device->expecting_cc_ua) {
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			/*
			 * Because some device does not queue unit
			 * attentions correctly, we carefully check
			 * additional sense code and qualifier so as
			 * not to squash media change unit attention.
			 */
			if (sshdr.asc != 0x28 || sshdr.ascq != 0x00) {
				scmd->device->expecting_cc_ua = 0;
				return NEEDS_RETRY;
			}
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		}
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		/*
		 * we might also expect a cc/ua if another LUN on the target
		 * reported a UA with an ASC/ASCQ of 3F 0E -
		 * REPORTED LUNS DATA HAS CHANGED.
		 */
		if (scmd->device->sdev_target->expecting_lun_change &&
		    sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
			return NEEDS_RETRY;
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		/*
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		 * if the device is in the process of becoming ready, we
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		 * should retry.
		 */
		if ((sshdr.asc == 0x04) && (sshdr.ascq == 0x01))
			return NEEDS_RETRY;
		/*
		 * if the device is not started, we need to wake
		 * the error handler to start the motor
		 */
		if (scmd->device->allow_restart &&
		    (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
			return FAILED;
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		/*
		 * Pass the UA upwards for a determination in the completion
		 * functions.
		 */
		return SUCCESS;
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		/* these are not supported */
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	case DATA_PROTECT:
		if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
			/* Thin provisioning hard threshold reached */
			set_host_byte(scmd, DID_ALLOC_FAILURE);
			return SUCCESS;
		}
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	case COPY_ABORTED:
	case VOLUME_OVERFLOW:
	case MISCOMPARE:
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	case BLANK_CHECK:
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		set_host_byte(scmd, DID_TARGET_FAILURE);
		return SUCCESS;
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	case MEDIUM_ERROR:
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		if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
		    sshdr.asc == 0x13 || /* AMNF DATA FIELD */
		    sshdr.asc == 0x14) { /* RECORD NOT FOUND */
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			set_host_byte(scmd, DID_MEDIUM_ERROR);
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			return SUCCESS;
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		}
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		return NEEDS_RETRY;

	case HARDWARE_ERROR:
		if (scmd->device->retry_hwerror)
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			return ADD_TO_MLQUEUE;
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		else
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			set_host_byte(scmd, DID_TARGET_FAILURE);
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	case ILLEGAL_REQUEST:
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		if (sshdr.asc == 0x20 || /* Invalid command operation code */
		    sshdr.asc == 0x21 || /* Logical block address out of range */
		    sshdr.asc == 0x24 || /* Invalid field in cdb */
		    sshdr.asc == 0x26) { /* Parameter value invalid */
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			set_host_byte(scmd, DID_TARGET_FAILURE);
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		}
		return SUCCESS;

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	default:
		return SUCCESS;
	}
}

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static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
{
	struct scsi_host_template *sht = sdev->host->hostt;
	struct scsi_device *tmp_sdev;

	if (!sht->change_queue_depth ||
	    sdev->queue_depth >= sdev->max_queue_depth)
		return;

	if (time_before(jiffies,
	    sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
		return;

	if (time_before(jiffies,
	    sdev->last_queue_full_time + sdev->queue_ramp_up_period))
		return;

	/*
	 * Walk all devices of a target and do
	 * ramp up on them.
	 */
	shost_for_each_device(tmp_sdev, sdev->host) {
		if (tmp_sdev->channel != sdev->channel ||
		    tmp_sdev->id != sdev->id ||
		    tmp_sdev->queue_depth == sdev->max_queue_depth)
			continue;
		/*
		 * call back into LLD to increase queue_depth by one
		 * with ramp up reason code.
		 */
		sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
					SCSI_QDEPTH_RAMP_UP);
		sdev->last_queue_ramp_up = jiffies;
	}
}

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static void scsi_handle_queue_full(struct scsi_device *sdev)
{
	struct scsi_host_template *sht = sdev->host->hostt;
	struct scsi_device *tmp_sdev;

	if (!sht->change_queue_depth)
		return;

	shost_for_each_device(tmp_sdev, sdev->host) {
		if (tmp_sdev->channel != sdev->channel ||
		    tmp_sdev->id != sdev->id)
			continue;
		/*
		 * We do not know the number of commands that were at
		 * the device when we got the queue full so we start
		 * from the highest possible value and work our way down.
		 */
		sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
					SCSI_QDEPTH_QFULL);
	}
}

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/**
 * scsi_eh_completed_normally - Disposition a eh cmd on return from LLD.
 * @scmd:	SCSI cmd to examine.
 *
 * Notes:
 *    This is *only* called when we are examining the status of commands
 *    queued during error recovery.  the main difference here is that we
 *    don't allow for the possibility of retries here, and we are a lot
 *    more restrictive about what we consider acceptable.
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 */
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static int scsi_eh_completed_normally(struct scsi_cmnd *scmd)
{
	/*
	 * first check the host byte, to see if there is anything in there
	 * that would indicate what we need to do.
	 */
	if (host_byte(scmd->result) == DID_RESET) {
		/*
		 * rats.  we are already in the error handler, so we now
		 * get to try and figure out what to do next.  if the sense
		 * is valid, we have a pretty good idea of what to do.
		 * if not, we mark it as FAILED.
		 */
		return scsi_check_sense(scmd);
	}
	if (host_byte(scmd->result) != DID_OK)
		return FAILED;

	/*
	 * next, check the message byte.
	 */
	if (msg_byte(scmd->result) != COMMAND_COMPLETE)
		return FAILED;

	/*
	 * now, check the status byte to see if this indicates
	 * anything special.
	 */
	switch (status_byte(scmd->result)) {
	case GOOD:
V
Vasu Dev 已提交
573
		scsi_handle_queue_ramp_up(scmd->device);
L
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574 575 576 577 578 579 580 581 582 583 584
	case COMMAND_TERMINATED:
		return SUCCESS;
	case CHECK_CONDITION:
		return scsi_check_sense(scmd);
	case CONDITION_GOOD:
	case INTERMEDIATE_GOOD:
	case INTERMEDIATE_C_GOOD:
		/*
		 * who knows?  FIXME(eric)
		 */
		return SUCCESS;
585
	case RESERVATION_CONFLICT:
586 587 588 589 590 591
		if (scmd->cmnd[0] == TEST_UNIT_READY)
			/* it is a success, we probed the device and
			 * found it */
			return SUCCESS;
		/* otherwise, we failed to send the command */
		return FAILED;
L
Linus Torvalds 已提交
592
	case QUEUE_FULL:
593 594 595
		scsi_handle_queue_full(scmd->device);
		/* fall through */
	case BUSY:
596
		return NEEDS_RETRY;
L
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597 598 599 600 601 602 603 604 605
	default:
		return FAILED;
	}
	return FAILED;
}

/**
 * scsi_eh_done - Completion function for error handling.
 * @scmd:	Cmd that is done.
606
 */
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607 608
static void scsi_eh_done(struct scsi_cmnd *scmd)
{
609
	struct completion *eh_action;
610

611 612
	SCSI_LOG_ERROR_RECOVERY(3,
		printk("%s scmd: %p result: %x\n",
613
			__func__, scmd, scmd->result));
614 615 616 617

	eh_action = scmd->device->host->eh_action;
	if (eh_action)
		complete(eh_action);
L
Linus Torvalds 已提交
618 619
}

620 621
/**
 * scsi_try_host_reset - ask host adapter to reset itself
G
Geert Uytterhoeven 已提交
622
 * @scmd:	SCSI cmd to send host reset.
623
 */
624 625 626 627
static int scsi_try_host_reset(struct scsi_cmnd *scmd)
{
	unsigned long flags;
	int rtn;
628 629
	struct Scsi_Host *host = scmd->device->host;
	struct scsi_host_template *hostt = host->hostt;
630 631

	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
632
					  __func__));
633

634
	if (!hostt->eh_host_reset_handler)
635 636
		return FAILED;

637
	rtn = hostt->eh_host_reset_handler(scmd);
638 639

	if (rtn == SUCCESS) {
640
		if (!hostt->skip_settle_delay)
641
			ssleep(HOST_RESET_SETTLE_TIME);
642 643 644
		spin_lock_irqsave(host->host_lock, flags);
		scsi_report_bus_reset(host, scmd_channel(scmd));
		spin_unlock_irqrestore(host->host_lock, flags);
645 646 647 648 649 650 651 652
	}

	return rtn;
}

/**
 * scsi_try_bus_reset - ask host to perform a bus reset
 * @scmd:	SCSI cmd to send bus reset.
653
 */
654 655 656 657
static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
{
	unsigned long flags;
	int rtn;
658 659
	struct Scsi_Host *host = scmd->device->host;
	struct scsi_host_template *hostt = host->hostt;
660 661

	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
662
					  __func__));
663

664
	if (!hostt->eh_bus_reset_handler)
665 666
		return FAILED;

667
	rtn = hostt->eh_bus_reset_handler(scmd);
668 669

	if (rtn == SUCCESS) {
670
		if (!hostt->skip_settle_delay)
671
			ssleep(BUS_RESET_SETTLE_TIME);
672 673 674
		spin_lock_irqsave(host->host_lock, flags);
		scsi_report_bus_reset(host, scmd_channel(scmd));
		spin_unlock_irqrestore(host->host_lock, flags);
675 676 677 678 679
	}

	return rtn;
}

680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699
static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
{
	sdev->was_reset = 1;
	sdev->expecting_cc_ua = 1;
}

/**
 * scsi_try_target_reset - Ask host to perform a target reset
 * @scmd:	SCSI cmd used to send a target reset
 *
 * Notes:
 *    There is no timeout for this operation.  if this operation is
 *    unreliable for a given host, then the host itself needs to put a
 *    timer on it, and set the host back to a consistent state prior to
 *    returning.
 */
static int scsi_try_target_reset(struct scsi_cmnd *scmd)
{
	unsigned long flags;
	int rtn;
700 701
	struct Scsi_Host *host = scmd->device->host;
	struct scsi_host_template *hostt = host->hostt;
702

703
	if (!hostt->eh_target_reset_handler)
704 705
		return FAILED;

706
	rtn = hostt->eh_target_reset_handler(scmd);
707
	if (rtn == SUCCESS) {
708
		spin_lock_irqsave(host->host_lock, flags);
709 710
		__starget_for_each_device(scsi_target(scmd->device), NULL,
					  __scsi_report_device_reset);
711
		spin_unlock_irqrestore(host->host_lock, flags);
712 713 714 715 716
	}

	return rtn;
}

717 718 719 720 721 722 723 724 725
/**
 * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
 * @scmd:	SCSI cmd used to send BDR
 *
 * Notes:
 *    There is no timeout for this operation.  if this operation is
 *    unreliable for a given host, then the host itself needs to put a
 *    timer on it, and set the host back to a consistent state prior to
 *    returning.
726
 */
727 728 729
static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
{
	int rtn;
730
	struct scsi_host_template *hostt = scmd->device->host->hostt;
731

732
	if (!hostt->eh_device_reset_handler)
733 734
		return FAILED;

735
	rtn = hostt->eh_device_reset_handler(scmd);
736 737
	if (rtn == SUCCESS)
		__scsi_report_device_reset(scmd->device, NULL);
738 739 740
	return rtn;
}

741
static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt, struct scsi_cmnd *scmd)
742
{
743
	if (!hostt->eh_abort_handler)
744 745
		return FAILED;

746
	return hostt->eh_abort_handler(scmd);
747 748 749 750
}

static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
{
751
	if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
752
		if (scsi_try_bus_device_reset(scmd) != SUCCESS)
753 754 755
			if (scsi_try_target_reset(scmd) != SUCCESS)
				if (scsi_try_bus_reset(scmd) != SUCCESS)
					scsi_try_host_reset(scmd);
756 757
}

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Linus Torvalds 已提交
758
/**
759
 * scsi_eh_prep_cmnd  - Save a scsi command info as part of error recovery
760
 * @scmd:       SCSI command structure to hijack
761
 * @ses:        structure to save restore information
762
 * @cmnd:       CDB to send. Can be NULL if no new cmnd is needed
763
 * @cmnd_size:  size in bytes of @cmnd (must be <= BLK_MAX_CDB)
764
 * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
765
 *
766
 * This function is used to save a scsi command information before re-execution
767 768 769 770
 * as part of the error recovery process.  If @sense_bytes is 0 the command
 * sent must be one that does not transfer any data.  If @sense_bytes != 0
 * @cmnd is ignored and this functions sets up a REQUEST_SENSE command
 * and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
771
 */
772 773
void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
			unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
L
Linus Torvalds 已提交
774
{
已提交
775
	struct scsi_device *sdev = scmd->device;
L
Linus Torvalds 已提交
776

777 778 779 780 781 782 783
	/*
	 * We need saved copies of a number of fields - this is because
	 * error handling may need to overwrite these with different values
	 * to run different commands, and once error handling is complete,
	 * we will need to restore these values prior to running the actual
	 * command.
	 */
784
	ses->cmd_len = scmd->cmd_len;
785
	ses->cmnd = scmd->cmnd;
786
	ses->data_direction = scmd->sc_data_direction;
B
Boaz Harrosh 已提交
787
	ses->sdb = scmd->sdb;
788
	ses->next_rq = scmd->request->next_rq;
789
	ses->result = scmd->result;
790
	ses->underflow = scmd->underflow;
791
	ses->prot_op = scmd->prot_op;
792

793
	scmd->prot_op = SCSI_PROT_NORMAL;
794 795
	scmd->cmnd = ses->eh_cmnd;
	memset(scmd->cmnd, 0, BLK_MAX_CDB);
B
Boaz Harrosh 已提交
796
	memset(&scmd->sdb, 0, sizeof(scmd->sdb));
797
	scmd->request->next_rq = NULL;
B
Boaz Harrosh 已提交
798

799
	if (sense_bytes) {
B
Boaz Harrosh 已提交
800 801
		scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
					 sense_bytes);
802
		sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
B
Boaz Harrosh 已提交
803 804
			    scmd->sdb.length);
		scmd->sdb.table.sgl = &ses->sense_sgl;
805
		scmd->sc_data_direction = DMA_FROM_DEVICE;
B
Boaz Harrosh 已提交
806
		scmd->sdb.table.nents = 1;
807
		scmd->cmnd[0] = REQUEST_SENSE;
B
Boaz Harrosh 已提交
808
		scmd->cmnd[4] = scmd->sdb.length;
809
		scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
810 811
	} else {
		scmd->sc_data_direction = DMA_NONE;
812
		if (cmnd) {
813
			BUG_ON(cmnd_size > BLK_MAX_CDB);
814 815 816
			memcpy(scmd->cmnd, cmnd, cmnd_size);
			scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
		}
817 818 819 820
	}

	scmd->underflow = 0;

821
	if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
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Linus Torvalds 已提交
822
		scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
已提交
823
			(sdev->lun << 5 & 0xe0);
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Linus Torvalds 已提交
824

825 826 827 828
	/*
	 * Zero the sense buffer.  The scsi spec mandates that any
	 * untransferred sense data should be interpreted as being zero.
	 */
829
	memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
830 831 832 833
}
EXPORT_SYMBOL(scsi_eh_prep_cmnd);

/**
834
 * scsi_eh_restore_cmnd  - Restore a scsi command info as part of error recovery
835
 * @scmd:       SCSI command structure to restore
836
 * @ses:        saved information from a coresponding call to scsi_eh_prep_cmnd
837
 *
838
 * Undo any damage done by above scsi_eh_prep_cmnd().
839
 */
840 841 842 843 844 845
void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
{
	/*
	 * Restore original data
	 */
	scmd->cmd_len = ses->cmd_len;
846
	scmd->cmnd = ses->cmnd;
847
	scmd->sc_data_direction = ses->data_direction;
B
Boaz Harrosh 已提交
848
	scmd->sdb = ses->sdb;
849
	scmd->request->next_rq = ses->next_rq;
850
	scmd->result = ses->result;
851
	scmd->underflow = ses->underflow;
852
	scmd->prot_op = ses->prot_op;
853 854
}
EXPORT_SYMBOL(scsi_eh_restore_cmnd);
855

856
/**
857
 * scsi_send_eh_cmnd  - submit a scsi command as part of error recovery
858 859 860 861 862 863 864 865 866 867 868
 * @scmd:       SCSI command structure to hijack
 * @cmnd:       CDB to send
 * @cmnd_size:  size in bytes of @cmnd
 * @timeout:    timeout for this request
 * @sense_bytes: size of sense data to copy or 0
 *
 * This function is used to send a scsi command down to a target device
 * as part of the error recovery process. See also scsi_eh_prep_cmnd() above.
 *
 * Return value:
 *    SUCCESS or FAILED or NEEDS_RETRY
869
 */
870 871 872 873 874 875
static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
			     int cmnd_size, int timeout, unsigned sense_bytes)
{
	struct scsi_device *sdev = scmd->device;
	struct Scsi_Host *shost = sdev->host;
	DECLARE_COMPLETION_ONSTACK(done);
876
	unsigned long timeleft = timeout;
877
	struct scsi_eh_save ses;
878
	const unsigned long stall_for = msecs_to_jiffies(100);
879 880
	int rtn;

881
retry:
882
	scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
883
	shost->eh_action = &done;
L
Linus Torvalds 已提交
884 885

	scsi_log_send(scmd);
J
Jeff Garzik 已提交
886
	scmd->scsi_done = scsi_eh_done;
887 888 889 890 891 892 893 894 895 896 897 898 899 900
	rtn = shost->hostt->queuecommand(shost, scmd);
	if (rtn) {
		if (timeleft > stall_for) {
			scsi_eh_restore_cmnd(scmd, &ses);
			timeleft -= stall_for;
			msleep(jiffies_to_msecs(stall_for));
			goto retry;
		}
		/* signal not to enter either branch of the if () below */
		timeleft = 0;
		rtn = NEEDS_RETRY;
	} else {
		timeleft = wait_for_completion_timeout(&done, timeout);
	}
L
Linus Torvalds 已提交
901

已提交
902
	shost->eh_action = NULL;
L
Linus Torvalds 已提交
903

904
	scsi_log_completion(scmd, rtn);
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Linus Torvalds 已提交
905

906 907
	SCSI_LOG_ERROR_RECOVERY(3,
		printk("%s: scmd: %p, timeleft: %ld\n",
908
			__func__, scmd, timeleft));
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Linus Torvalds 已提交
909 910

	/*
911 912 913 914 915 916 917
	 * If there is time left scsi_eh_done got called, and we will examine
	 * the actual status codes to see whether the command actually did
	 * complete normally, else if we have a zero return and no time left,
	 * the command must still be pending, so abort it and return FAILED.
	 * If we never actually managed to issue the command, because
	 * ->queuecommand() kept returning non zero, use the rtn = FAILED
	 * value above (so don't execute either branch of the if)
L
Linus Torvalds 已提交
918
	 */
919
	if (timeleft) {
L
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920 921 922
		rtn = scsi_eh_completed_normally(scmd);
		SCSI_LOG_ERROR_RECOVERY(3,
			printk("%s: scsi_eh_completed_normally %x\n",
923
			       __func__, rtn));
924

L
Linus Torvalds 已提交
925 926 927 928 929
		switch (rtn) {
		case SUCCESS:
		case NEEDS_RETRY:
		case FAILED:
			break;
930 931 932
		case ADD_TO_MLQUEUE:
			rtn = NEEDS_RETRY;
			break;
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Linus Torvalds 已提交
933 934 935 936
		default:
			rtn = FAILED;
			break;
		}
937
	} else if (!rtn) {
938
		scsi_abort_eh_cmnd(scmd);
939
		rtn = FAILED;
L
Linus Torvalds 已提交
940 941
	}

942
	scsi_eh_restore_cmnd(scmd, &ses);
943

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Linus Torvalds 已提交
944 945 946 947 948 949 950 951 952 953 954
	return rtn;
}

/**
 * scsi_request_sense - Request sense data from a particular target.
 * @scmd:	SCSI cmd for request sense.
 *
 * Notes:
 *    Some hosts automatically obtain this information, others require
 *    that we obtain it on our own. This function will *not* return until
 *    the command either times out, or it completes.
955
 */
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956 957
static int scsi_request_sense(struct scsi_cmnd *scmd)
{
958
	return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
L
Linus Torvalds 已提交
959 960
}

961 962 963 964 965 966 967 968 969 970
static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
{
	if (scmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
		struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
		if (sdrv->eh_action)
			rtn = sdrv->eh_action(scmd, rtn);
	}
	return rtn;
}

L
Linus Torvalds 已提交
971 972 973 974 975 976 977 978
/**
 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 * @scmd:	Original SCSI cmd that eh has finished.
 * @done_q:	Queue for processed commands.
 *
 * Notes:
 *    We don't want to use the normal command completion while we are are
 *    still handling errors - it may cause other commands to be queued,
979
 *    and that would disturb what we are doing.  Thus we really want to
L
Linus Torvalds 已提交
980 981
 *    keep a list of pending commands for final completion, and once we
 *    are ready to leave error handling we handle completion for real.
982
 */
983
void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
L
Linus Torvalds 已提交
984 985
{
	scmd->device->host->host_failed--;
986
	scmd->eh_eflags = 0;
L
Linus Torvalds 已提交
987 988
	list_move_tail(&scmd->eh_entry, done_q);
}
989
EXPORT_SYMBOL(scsi_eh_finish_cmd);
L
Linus Torvalds 已提交
990 991 992 993

/**
 * scsi_eh_get_sense - Get device sense data.
 * @work_q:	Queue of commands to process.
994
 * @done_q:	Queue of processed commands.
L
Linus Torvalds 已提交
995 996 997
 *
 * Description:
 *    See if we need to request sense information.  if so, then get it
998
 *    now, so we have a better idea of what to do.
L
Linus Torvalds 已提交
999 1000 1001
 *
 * Notes:
 *    This has the unfortunate side effect that if a shost adapter does
1002
 *    not automatically request sense information, we end up shutting
L
Linus Torvalds 已提交
1003 1004 1005 1006 1007 1008 1009
 *    it down before we request it.
 *
 *    All drivers should request sense information internally these days,
 *    so for now all I have to say is tough noogies if you end up in here.
 *
 *    XXX: Long term this code should go away, but that needs an audit of
 *         all LLDDs first.
1010
 */
1011 1012
int scsi_eh_get_sense(struct list_head *work_q,
		      struct list_head *done_q)
L
Linus Torvalds 已提交
1013
{
1014
	struct scsi_cmnd *scmd, *next;
1015
	struct Scsi_Host *shost;
L
Linus Torvalds 已提交
1016
	int rtn;
1017
	unsigned long flags;
L
Linus Torvalds 已提交
1018

1019
	list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1020
		if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
L
Linus Torvalds 已提交
1021 1022 1023
		    SCSI_SENSE_VALID(scmd))
			continue;

1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034
		shost = scmd->device->host;
		spin_lock_irqsave(shost->host_lock, flags);
		if (scsi_host_eh_past_deadline(shost)) {
			spin_unlock_irqrestore(shost->host_lock, flags);
			SCSI_LOG_ERROR_RECOVERY(3,
				shost_printk(KERN_INFO, shost,
					    "skip %s, past eh deadline\n",
					     __func__));
			break;
		}
		spin_unlock_irqrestore(shost->host_lock, flags);
1035 1036 1037
		SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
						  "%s: requesting sense\n",
						  current->comm));
L
Linus Torvalds 已提交
1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066
		rtn = scsi_request_sense(scmd);
		if (rtn != SUCCESS)
			continue;

		SCSI_LOG_ERROR_RECOVERY(3, printk("sense requested for %p"
						  " result %x\n", scmd,
						  scmd->result));
		SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));

		rtn = scsi_decide_disposition(scmd);

		/*
		 * if the result was normal, then just pass it along to the
		 * upper level.
		 */
		if (rtn == SUCCESS)
			/* we don't want this command reissued, just
			 * finished with the sense data, so set
			 * retries to the max allowed to ensure it
			 * won't get reissued */
			scmd->retries = scmd->allowed;
		else if (rtn != NEEDS_RETRY)
			continue;

		scsi_eh_finish_cmd(scmd, done_q);
	}

	return list_empty(work_q);
}
1067
EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
L
Linus Torvalds 已提交
1068 1069 1070

/**
 * scsi_eh_tur - Send TUR to device.
1071
 * @scmd:	&scsi_cmnd to send TUR
L
Linus Torvalds 已提交
1072 1073 1074
 *
 * Return value:
 *    0 - Device is ready. 1 - Device NOT ready.
1075
 */
L
Linus Torvalds 已提交
1076 1077 1078 1079 1080 1081
static int scsi_eh_tur(struct scsi_cmnd *scmd)
{
	static unsigned char tur_command[6] = {TEST_UNIT_READY, 0, 0, 0, 0, 0};
	int retry_cnt = 1, rtn;

retry_tur:
1082 1083
	rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
				scmd->device->eh_timeout, 0);
L
Linus Torvalds 已提交
1084 1085

	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
1086
		__func__, scmd, rtn));
1087 1088 1089

	switch (rtn) {
	case NEEDS_RETRY:
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		if (retry_cnt--)
			goto retry_tur;
1092 1093
		/*FALLTHRU*/
	case SUCCESS:
1094
		return 0;
1095 1096
	default:
		return 1;
1097
	}
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}

1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119
/**
 * scsi_eh_test_devices - check if devices are responding from error recovery.
 * @cmd_list:	scsi commands in error recovery.
 * @work_q:     queue for commands which still need more error recovery
 * @done_q:     queue for commands which are finished
 * @try_stu:    boolean on if a STU command should be tried in addition to TUR.
 *
 * Decription:
 *    Tests if devices are in a working state.  Commands to devices now in
 *    a working state are sent to the done_q while commands to devices which
 *    are still failing to respond are returned to the work_q for more
 *    processing.
 **/
static int scsi_eh_test_devices(struct list_head *cmd_list,
				struct list_head *work_q,
				struct list_head *done_q, int try_stu)
{
	struct scsi_cmnd *scmd, *next;
	struct scsi_device *sdev;
	int finish_cmds;
1120
	unsigned long flags;
1121 1122 1123 1124 1125

	while (!list_empty(cmd_list)) {
		scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
		sdev = scmd->device;

1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141
		if (!try_stu) {
			spin_lock_irqsave(sdev->host->host_lock, flags);
			if (scsi_host_eh_past_deadline(sdev->host)) {
				/* Push items back onto work_q */
				list_splice_init(cmd_list, work_q);
				spin_unlock_irqrestore(sdev->host->host_lock,
						       flags);
				SCSI_LOG_ERROR_RECOVERY(3,
					shost_printk(KERN_INFO, sdev->host,
						     "skip %s, past eh deadline",
						     __func__));
				break;
			}
			spin_unlock_irqrestore(sdev->host->host_lock, flags);
		}

1142 1143 1144 1145 1146 1147 1148
		finish_cmds = !scsi_device_online(scmd->device) ||
			(try_stu && !scsi_eh_try_stu(scmd) &&
			 !scsi_eh_tur(scmd)) ||
			!scsi_eh_tur(scmd);

		list_for_each_entry_safe(scmd, next, cmd_list, eh_entry)
			if (scmd->device == sdev) {
1149 1150 1151
				if (finish_cmds &&
				    (try_stu ||
				     scsi_eh_action(scmd, SUCCESS) == SUCCESS))
1152 1153 1154 1155 1156 1157 1158 1159 1160
					scsi_eh_finish_cmd(scmd, done_q);
				else
					list_move_tail(&scmd->eh_entry, work_q);
			}
	}
	return list_empty(work_q);
}


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/**
1162 1163 1164
 * scsi_eh_abort_cmds - abort pending commands.
 * @work_q:	&list_head for pending commands.
 * @done_q:	&list_head for processed commands.
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 *
 * Decription:
 *    Try and see whether or not it makes sense to try and abort the
1168 1169
 *    running command.  This only works out to be the case if we have one
 *    command that has timed out.  If the command simply failed, it makes
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 *    no sense to try and abort the command, since as far as the shost
 *    adapter is concerned, it isn't running.
1172
 */
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static int scsi_eh_abort_cmds(struct list_head *work_q,
			      struct list_head *done_q)
{
1176
	struct scsi_cmnd *scmd, *next;
1177
	LIST_HEAD(check_list);
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	int rtn;
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	struct Scsi_Host *shost;
	unsigned long flags;
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1182
	list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1183
		if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
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			continue;
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196
		shost = scmd->device->host;
		spin_lock_irqsave(shost->host_lock, flags);
		if (scsi_host_eh_past_deadline(shost)) {
			spin_unlock_irqrestore(shost->host_lock, flags);
			list_splice_init(&check_list, work_q);
			SCSI_LOG_ERROR_RECOVERY(3,
				shost_printk(KERN_INFO, shost,
					    "skip %s, past eh deadline\n",
					     __func__));
			return list_empty(work_q);
		}
		spin_unlock_irqrestore(shost->host_lock, flags);
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		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
						  "0x%p\n", current->comm,
						  scmd));
1200
		rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
1201
		if (rtn == FAILED) {
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			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
							  " cmd failed:"
							  "0x%p\n",
							  current->comm,
							  scmd));
1207 1208 1209 1210 1211 1212 1213 1214
			list_splice_init(&check_list, work_q);
			return list_empty(work_q);
		}
		scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
		if (rtn == FAST_IO_FAIL)
			scsi_eh_finish_cmd(scmd, done_q);
		else
			list_move_tail(&scmd->eh_entry, &check_list);
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	}

1217
	return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
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}

/**
 * scsi_eh_try_stu - Send START_UNIT to device.
1222
 * @scmd:	&scsi_cmnd to send START_UNIT
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 *
 * Return value:
 *    0 - Device is ready. 1 - Device NOT ready.
1226
 */
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static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
{
	static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};

1231
	if (scmd->device->allow_restart) {
1232 1233 1234
		int i, rtn = NEEDS_RETRY;

		for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
1235
			rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
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1237 1238 1239
		if (rtn == SUCCESS)
			return 0;
	}
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	return 1;
}

 /**
 * scsi_eh_stu - send START_UNIT if needed
1246 1247 1248
 * @shost:	&scsi host being recovered.
 * @work_q:     &list_head for pending commands.
 * @done_q:	&list_head for processed commands.
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 *
 * Notes:
 *    If commands are failing due to not ready, initializing command required,
1252
 *	try revalidating the device, which will end up sending a start unit.
1253
 */
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static int scsi_eh_stu(struct Scsi_Host *shost,
			      struct list_head *work_q,
			      struct list_head *done_q)
{
1258
	struct scsi_cmnd *scmd, *stu_scmd, *next;
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	struct scsi_device *sdev;
1260
	unsigned long flags;
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	shost_for_each_device(sdev, shost) {
1263 1264 1265 1266 1267 1268 1269 1270 1271 1272
		spin_lock_irqsave(shost->host_lock, flags);
		if (scsi_host_eh_past_deadline(shost)) {
			spin_unlock_irqrestore(shost->host_lock, flags);
			SCSI_LOG_ERROR_RECOVERY(3,
				shost_printk(KERN_INFO, shost,
					    "skip %s, past eh deadline\n",
					     __func__));
			break;
		}
		spin_unlock_irqrestore(shost->host_lock, flags);
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		stu_scmd = NULL;
		list_for_each_entry(scmd, work_q, eh_entry)
			if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
			    scsi_check_sense(scmd) == FAILED ) {
				stu_scmd = scmd;
				break;
			}

		if (!stu_scmd)
			continue;

		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
						  " 0x%p\n", current->comm, sdev));

		if (!scsi_eh_try_stu(stu_scmd)) {
			if (!scsi_device_online(sdev) ||
			    !scsi_eh_tur(stu_scmd)) {
1290 1291
				list_for_each_entry_safe(scmd, next,
							  work_q, eh_entry) {
1292 1293
					if (scmd->device == sdev &&
					    scsi_eh_action(scmd, SUCCESS) == SUCCESS)
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						scsi_eh_finish_cmd(scmd, done_q);
				}
			}
		} else {
			SCSI_LOG_ERROR_RECOVERY(3,
						printk("%s: START_UNIT failed to sdev:"
						       " 0x%p\n", current->comm, sdev));
		}
	}

	return list_empty(work_q);
}


/**
 * scsi_eh_bus_device_reset - send bdr if needed
 * @shost:	scsi host being recovered.
1311 1312
 * @work_q:     &list_head for pending commands.
 * @done_q:	&list_head for processed commands.
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 *
 * Notes:
1315
 *    Try a bus device reset.  Still, look to see whether we have multiple
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 *    devices that are jammed or not - if we have multiple devices, it
 *    makes no sense to try bus_device_reset - we really would need to try
1318
 *    a bus_reset instead.
1319
 */
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static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
				    struct list_head *work_q,
				    struct list_head *done_q)
{
1324
	struct scsi_cmnd *scmd, *bdr_scmd, *next;
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	struct scsi_device *sdev;
1326
	unsigned long flags;
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	int rtn;

	shost_for_each_device(sdev, shost) {
1330 1331 1332 1333 1334 1335 1336 1337 1338 1339
		spin_lock_irqsave(shost->host_lock, flags);
		if (scsi_host_eh_past_deadline(shost)) {
			spin_unlock_irqrestore(shost->host_lock, flags);
			SCSI_LOG_ERROR_RECOVERY(3,
				shost_printk(KERN_INFO, shost,
					    "skip %s, past eh deadline\n",
					     __func__));
			break;
		}
		spin_unlock_irqrestore(shost->host_lock, flags);
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		bdr_scmd = NULL;
		list_for_each_entry(scmd, work_q, eh_entry)
			if (scmd->device == sdev) {
				bdr_scmd = scmd;
				break;
			}

		if (!bdr_scmd)
			continue;

		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
						  " 0x%p\n", current->comm,
						  sdev));
		rtn = scsi_try_bus_device_reset(bdr_scmd);
1354
		if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
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			if (!scsi_device_online(sdev) ||
1356
			    rtn == FAST_IO_FAIL ||
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			    !scsi_eh_tur(bdr_scmd)) {
1358 1359
				list_for_each_entry_safe(scmd, next,
							 work_q, eh_entry) {
1360 1361
					if (scmd->device == sdev &&
					    scsi_eh_action(scmd, rtn) != FAILED)
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						scsi_eh_finish_cmd(scmd,
								   done_q);
				}
			}
		} else {
			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
							  " failed sdev:"
							  "0x%p\n",
							  current->comm,
							   sdev));
		}
	}

	return list_empty(work_q);
}

1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390
/**
 * scsi_eh_target_reset - send target reset if needed
 * @shost:	scsi host being recovered.
 * @work_q:     &list_head for pending commands.
 * @done_q:	&list_head for processed commands.
 *
 * Notes:
 *    Try a target reset.
 */
static int scsi_eh_target_reset(struct Scsi_Host *shost,
				struct list_head *work_q,
				struct list_head *done_q)
{
1391
	LIST_HEAD(tmp_list);
1392
	LIST_HEAD(check_list);
1393

1394 1395 1396 1397 1398 1399
	list_splice_init(work_q, &tmp_list);

	while (!list_empty(&tmp_list)) {
		struct scsi_cmnd *next, *scmd;
		int rtn;
		unsigned int id;
1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414
		unsigned long flags;

		spin_lock_irqsave(shost->host_lock, flags);
		if (scsi_host_eh_past_deadline(shost)) {
			spin_unlock_irqrestore(shost->host_lock, flags);
			/* push back on work queue for further processing */
			list_splice_init(&check_list, work_q);
			list_splice_init(&tmp_list, work_q);
			SCSI_LOG_ERROR_RECOVERY(3,
				shost_printk(KERN_INFO, shost,
					    "skip %s, past eh deadline\n",
					     __func__));
			return list_empty(work_q);
		}
		spin_unlock_irqrestore(shost->host_lock, flags);
1415 1416 1417

		scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
		id = scmd_id(scmd);
1418 1419 1420 1421

		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
						  "to target %d\n",
						  current->comm, id));
1422 1423
		rtn = scsi_try_target_reset(scmd);
		if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
1424 1425 1426 1427
			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
							  " failed target: "
							  "%d\n",
							  current->comm, id));
1428 1429 1430 1431
		list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
			if (scmd_id(scmd) != id)
				continue;

1432 1433 1434
			if (rtn == SUCCESS)
				list_move_tail(&scmd->eh_entry, &check_list);
			else if (rtn == FAST_IO_FAIL)
1435 1436 1437 1438 1439 1440
				scsi_eh_finish_cmd(scmd, done_q);
			else
				/* push back on work queue for further processing */
				list_move(&scmd->eh_entry, work_q);
		}
	}
1441

1442
	return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
1443 1444
}

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/**
1446
 * scsi_eh_bus_reset - send a bus reset
1447 1448 1449
 * @shost:	&scsi host being recovered.
 * @work_q:     &list_head for pending commands.
 * @done_q:	&list_head for processed commands.
1450
 */
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static int scsi_eh_bus_reset(struct Scsi_Host *shost,
			     struct list_head *work_q,
			     struct list_head *done_q)
{
1455
	struct scsi_cmnd *scmd, *chan_scmd, *next;
1456
	LIST_HEAD(check_list);
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1457 1458
	unsigned int channel;
	int rtn;
1459
	unsigned long flags;
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	/*
	 * we really want to loop over the various channels, and do this on
	 * a channel by channel basis.  we should also check to see if any
	 * of the failed commands are on soft_reset devices, and if so, skip
1465
	 * the reset.
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1466 1467 1468
	 */

	for (channel = 0; channel <= shost->max_channel; channel++) {
1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480
		spin_lock_irqsave(shost->host_lock, flags);
		if (scsi_host_eh_past_deadline(shost)) {
			spin_unlock_irqrestore(shost->host_lock, flags);
			list_splice_init(&check_list, work_q);
			SCSI_LOG_ERROR_RECOVERY(3,
				shost_printk(KERN_INFO, shost,
					    "skip %s, past eh deadline\n",
					     __func__));
			return list_empty(work_q);
		}
		spin_unlock_irqrestore(shost->host_lock, flags);

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		chan_scmd = NULL;
		list_for_each_entry(scmd, work_q, eh_entry) {
1483
			if (channel == scmd_channel(scmd)) {
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				chan_scmd = scmd;
				break;
				/*
				 * FIXME add back in some support for
				 * soft_reset devices.
				 */
			}
		}

		if (!chan_scmd)
			continue;
		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BRST chan:"
						  " %d\n", current->comm,
						  channel));
		rtn = scsi_try_bus_reset(chan_scmd);
1499
		if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
1500
			list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1501 1502
				if (channel == scmd_channel(scmd)) {
					if (rtn == FAST_IO_FAIL)
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						scsi_eh_finish_cmd(scmd,
								   done_q);
1505 1506 1507 1508
					else
						list_move_tail(&scmd->eh_entry,
							       &check_list);
				}
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			}
		} else {
			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
							  " failed chan: %d\n",
							  current->comm,
							  channel));
		}
	}
1517
	return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
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}

/**
1521
 * scsi_eh_host_reset - send a host reset
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1522 1523
 * @work_q:	list_head for processed commands.
 * @done_q:	list_head for processed commands.
1524
 */
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static int scsi_eh_host_reset(struct list_head *work_q,
			      struct list_head *done_q)
{
1528
	struct scsi_cmnd *scmd, *next;
1529
	LIST_HEAD(check_list);
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	int rtn;

	if (!list_empty(work_q)) {
		scmd = list_entry(work_q->next,
				  struct scsi_cmnd, eh_entry);

		SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending HRST\n"
						  , current->comm));

		rtn = scsi_try_host_reset(scmd);
1540 1541 1542
		if (rtn == SUCCESS) {
			list_splice_init(work_q, &check_list);
		} else if (rtn == FAST_IO_FAIL) {
1543
			list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
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					scsi_eh_finish_cmd(scmd, done_q);
			}
		} else {
			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
							  " failed\n",
							  current->comm));
		}
	}
1552
	return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
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}

/**
 * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
 * @work_q:	list_head for processed commands.
 * @done_q:	list_head for processed commands.
1559
 */
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static void scsi_eh_offline_sdevs(struct list_head *work_q,
				  struct list_head *done_q)
{
1563
	struct scsi_cmnd *scmd, *next;
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1565
	list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
1566 1567
		sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
			    "not ready after error recovery\n");
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		scsi_device_set_state(scmd->device, SDEV_OFFLINE);
1569
		if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
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			/*
			 * FIXME: Handle lost cmds.
			 */
		}
		scsi_eh_finish_cmd(scmd, done_q);
	}
	return;
}

1579 1580 1581 1582 1583 1584 1585 1586 1587 1588
/**
 * scsi_noretry_cmd - determinte if command should be failed fast
 * @scmd:	SCSI cmd to examine.
 */
int scsi_noretry_cmd(struct scsi_cmnd *scmd)
{
	switch (host_byte(scmd->result)) {
	case DID_OK:
		break;
	case DID_BUS_BUSY:
1589
		return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
1590
	case DID_PARITY:
1591
		return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
1592 1593 1594 1595 1596 1597
	case DID_ERROR:
		if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
		    status_byte(scmd->result) == RESERVATION_CONFLICT)
			return 0;
		/* fall through */
	case DID_SOFT_ERROR:
1598
		return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
1599 1600 1601 1602 1603 1604 1605 1606
	}

	switch (status_byte(scmd->result)) {
	case CHECK_CONDITION:
		/*
		 * assume caller has checked sense and determinted
		 * the check condition was retryable.
		 */
1607 1608 1609
		if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
		    scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
			return 1;
1610 1611 1612 1613 1614
	}

	return 0;
}

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Linus Torvalds 已提交
1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
/**
 * scsi_decide_disposition - Disposition a cmd on return from LLD.
 * @scmd:	SCSI cmd to examine.
 *
 * Notes:
 *    This is *only* called when we are examining the status after sending
 *    out the actual data command.  any commands that are queued for error
 *    recovery (e.g. test_unit_ready) do *not* come through here.
 *
 *    When this routine returns failed, it means the error handler thread
 *    is woken.  In cases where the error code indicates an error that
 *    doesn't require the error handler read (i.e. we don't need to
 *    abort/reset), this function should return SUCCESS.
1628
 */
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Linus Torvalds 已提交
1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639
int scsi_decide_disposition(struct scsi_cmnd *scmd)
{
	int rtn;

	/*
	 * if the device is offline, then we clearly just pass the result back
	 * up to the top level.
	 */
	if (!scsi_device_online(scmd->device)) {
		SCSI_LOG_ERROR_RECOVERY(5, printk("%s: device offline - report"
						  " as SUCCESS\n",
1640
						  __func__));
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Linus Torvalds 已提交
1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672
		return SUCCESS;
	}

	/*
	 * first check the host byte, to see if there is anything in there
	 * that would indicate what we need to do.
	 */
	switch (host_byte(scmd->result)) {
	case DID_PASSTHROUGH:
		/*
		 * no matter what, pass this through to the upper layer.
		 * nuke this special code so that it looks like we are saying
		 * did_ok.
		 */
		scmd->result &= 0xff00ffff;
		return SUCCESS;
	case DID_OK:
		/*
		 * looks good.  drop through, and check the next byte.
		 */
		break;
	case DID_NO_CONNECT:
	case DID_BAD_TARGET:
	case DID_ABORT:
		/*
		 * note - this means that we just report the status back
		 * to the top level driver, not that we actually think
		 * that it indicates SUCCESS.
		 */
		return SUCCESS;
		/*
		 * when the low level driver returns did_soft_error,
1673
		 * it is responsible for keeping an internal retry counter
L
Linus Torvalds 已提交
1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684
		 * in order to avoid endless loops (db)
		 *
		 * actually this is a bug in this function here.  we should
		 * be mindful of the maximum number of retries specified
		 * and not get stuck in a loop.
		 */
	case DID_SOFT_ERROR:
		goto maybe_retry;
	case DID_IMM_RETRY:
		return NEEDS_RETRY;

已提交
1685 1686
	case DID_REQUEUE:
		return ADD_TO_MLQUEUE;
1687 1688 1689 1690 1691
	case DID_TRANSPORT_DISRUPTED:
		/*
		 * LLD/transport was disrupted during processing of the IO.
		 * The transport class is now blocked/blocking,
		 * and the transport will decide what to do with the IO
1692 1693
		 * based on its timers and recovery capablilities if
		 * there are enough retries.
1694
		 */
1695
		goto maybe_retry;
1696 1697 1698 1699 1700 1701
	case DID_TRANSPORT_FAILFAST:
		/*
		 * The transport decided to failfast the IO (most likely
		 * the fast io fail tmo fired), so send IO directly upwards.
		 */
		return SUCCESS;
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1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742
	case DID_ERROR:
		if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
		    status_byte(scmd->result) == RESERVATION_CONFLICT)
			/*
			 * execute reservation conflict processing code
			 * lower down
			 */
			break;
		/* fallthrough */
	case DID_BUS_BUSY:
	case DID_PARITY:
		goto maybe_retry;
	case DID_TIME_OUT:
		/*
		 * when we scan the bus, we get timeout messages for
		 * these commands if there is no device available.
		 * other hosts report did_no_connect for the same thing.
		 */
		if ((scmd->cmnd[0] == TEST_UNIT_READY ||
		     scmd->cmnd[0] == INQUIRY)) {
			return SUCCESS;
		} else {
			return FAILED;
		}
	case DID_RESET:
		return SUCCESS;
	default:
		return FAILED;
	}

	/*
	 * next, check the message byte.
	 */
	if (msg_byte(scmd->result) != COMMAND_COMPLETE)
		return FAILED;

	/*
	 * check the status byte to see if this indicates anything special.
	 */
	switch (status_byte(scmd->result)) {
	case QUEUE_FULL:
1743
		scsi_handle_queue_full(scmd->device);
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Linus Torvalds 已提交
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		/*
		 * the case of trying to send too many commands to a
		 * tagged queueing device.
		 */
	case BUSY:
		/*
		 * device can't talk to us at the moment.  Should only
		 * occur (SAM-3) when the task queue is empty, so will cause
		 * the empty queue handling to trigger a stall in the
		 * device.
		 */
		return ADD_TO_MLQUEUE;
	case GOOD:
1757 1758
		if (scmd->cmnd[0] == REPORT_LUNS)
			scmd->device->sdev_target->expecting_lun_change = 0;
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Vasu Dev 已提交
1759
		scsi_handle_queue_ramp_up(scmd->device);
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	case COMMAND_TERMINATED:
		return SUCCESS;
1762 1763
	case TASK_ABORTED:
		goto maybe_retry;
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	case CHECK_CONDITION:
		rtn = scsi_check_sense(scmd);
		if (rtn == NEEDS_RETRY)
			goto maybe_retry;
		/* if rtn == FAILED, we have no sense information;
		 * returning FAILED will wake the error handler thread
		 * to collect the sense and redo the decide
		 * disposition */
		return rtn;
	case CONDITION_GOOD:
	case INTERMEDIATE_GOOD:
	case INTERMEDIATE_C_GOOD:
	case ACA_ACTIVE:
		/*
		 * who knows?  FIXME(eric)
		 */
		return SUCCESS;

	case RESERVATION_CONFLICT:
1783 1784
		sdev_printk(KERN_INFO, scmd->device,
			    "reservation conflict\n");
1785
		set_host_byte(scmd, DID_NEXUS_FAILURE);
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		return SUCCESS; /* causes immediate i/o error */
	default:
		return FAILED;
	}
	return FAILED;

      maybe_retry:

	/* we requeue for retry because the error was retryable, and
	 * the request was not marked fast fail.  Note that above,
	 * even if the request is marked fast fail, we still requeue
	 * for queue congestion conditions (QUEUE_FULL or BUSY) */
1798
	if ((++scmd->retries) <= scmd->allowed
1799
	    && !scsi_noretry_cmd(scmd)) {
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Linus Torvalds 已提交
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		return NEEDS_RETRY;
	} else {
		/*
		 * no more retries - report this one back to upper level.
		 */
		return SUCCESS;
	}
}

F
FUJITA Tomonori 已提交
1809 1810 1811 1812 1813
static void eh_lock_door_done(struct request *req, int uptodate)
{
	__blk_put_request(req->q, req);
}

L
Linus Torvalds 已提交
1814 1815 1816 1817 1818
/**
 * scsi_eh_lock_door - Prevent medium removal for the specified device
 * @sdev:	SCSI device to prevent medium removal
 *
 * Locking:
1819
 * 	We must be called from process context.
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Linus Torvalds 已提交
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 *
 * Notes:
 * 	We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
 * 	head of the devices request queue, and continue.
1824
 */
L
Linus Torvalds 已提交
1825 1826
static void scsi_eh_lock_door(struct scsi_device *sdev)
{
F
FUJITA Tomonori 已提交
1827
	struct request *req;
L
Linus Torvalds 已提交
1828

1829 1830 1831 1832
	/*
	 * blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
	 * request becomes available
	 */
F
FUJITA Tomonori 已提交
1833
	req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
L
Linus Torvalds 已提交
1834

F
FUJITA Tomonori 已提交
1835 1836 1837 1838 1839 1840
	req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
	req->cmd[1] = 0;
	req->cmd[2] = 0;
	req->cmd[3] = 0;
	req->cmd[4] = SCSI_REMOVAL_PREVENT;
	req->cmd[5] = 0;
L
Linus Torvalds 已提交
1841

F
FUJITA Tomonori 已提交
1842 1843 1844 1845 1846 1847 1848 1849 1850
	req->cmd_len = COMMAND_SIZE(req->cmd[0]);

	req->cmd_type = REQ_TYPE_BLOCK_PC;
	req->cmd_flags |= REQ_QUIET;
	req->timeout = 10 * HZ;
	req->retries = 5;

	blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
}
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Linus Torvalds 已提交
1851 1852 1853 1854 1855 1856 1857 1858

/**
 * scsi_restart_operations - restart io operations to the specified host.
 * @shost:	Host we are restarting.
 *
 * Notes:
 *    When we entered the error handler, we blocked all further i/o to
 *    this device.  we need to 'reverse' this process.
1859
 */
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Linus Torvalds 已提交
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static void scsi_restart_operations(struct Scsi_Host *shost)
{
	struct scsi_device *sdev;
1863
	unsigned long flags;
L
Linus Torvalds 已提交
1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879

	/*
	 * If the door was locked, we need to insert a door lock request
	 * onto the head of the SCSI request queue for the device.  There
	 * is no point trying to lock the door of an off-line device.
	 */
	shost_for_each_device(sdev, shost) {
		if (scsi_device_online(sdev) && sdev->locked)
			scsi_eh_lock_door(sdev);
	}

	/*
	 * next free up anything directly waiting upon the host.  this
	 * will be requests for character device operations, and also for
	 * ioctls to queued block devices.
	 */
1880 1881 1882
	SCSI_LOG_ERROR_RECOVERY(3,
		printk("scsi_eh_%d waking up host to restart\n",
		       shost->host_no));
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Linus Torvalds 已提交
1883

1884 1885 1886 1887 1888
	spin_lock_irqsave(shost->host_lock, flags);
	if (scsi_host_set_state(shost, SHOST_RUNNING))
		if (scsi_host_set_state(shost, SHOST_CANCEL))
			BUG_ON(scsi_host_set_state(shost, SHOST_DEL));
	spin_unlock_irqrestore(shost->host_lock, flags);
L
Linus Torvalds 已提交
1889 1890 1891 1892 1893 1894 1895 1896 1897 1898

	wake_up(&shost->host_wait);

	/*
	 * finally we need to re-initiate requests that may be pending.  we will
	 * have had everything blocked while error handling is taking place, and
	 * now that error recovery is done, we will need to ensure that these
	 * requests are started.
	 */
	scsi_run_host_queues(shost);
1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912

	/*
	 * if eh is active and host_eh_scheduled is pending we need to re-run
	 * recovery.  we do this check after scsi_run_host_queues() to allow
	 * everything pent up since the last eh run a chance to make forward
	 * progress before we sync again.  Either we'll immediately re-run
	 * recovery or scsi_device_unbusy() will wake us again when these
	 * pending commands complete.
	 */
	spin_lock_irqsave(shost->host_lock, flags);
	if (shost->host_eh_scheduled)
		if (scsi_host_set_state(shost, SHOST_RECOVERY))
			WARN_ON(scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY));
	spin_unlock_irqrestore(shost->host_lock, flags);
L
Linus Torvalds 已提交
1913 1914 1915 1916 1917
}

/**
 * scsi_eh_ready_devs - check device ready state and recover if not.
 * @shost: 	host to be recovered.
1918 1919
 * @work_q:     &list_head for pending commands.
 * @done_q:	&list_head for processed commands.
1920
 */
1921 1922 1923
void scsi_eh_ready_devs(struct Scsi_Host *shost,
			struct list_head *work_q,
			struct list_head *done_q)
L
Linus Torvalds 已提交
1924 1925 1926
{
	if (!scsi_eh_stu(shost, work_q, done_q))
		if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
1927 1928 1929 1930 1931
			if (!scsi_eh_target_reset(shost, work_q, done_q))
				if (!scsi_eh_bus_reset(shost, work_q, done_q))
					if (!scsi_eh_host_reset(work_q, done_q))
						scsi_eh_offline_sdevs(work_q,
								      done_q);
L
Linus Torvalds 已提交
1932
}
1933
EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
L
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1934 1935 1936 1937

/**
 * scsi_eh_flush_done_q - finish processed commands or retry them.
 * @done_q:	list_head of processed commands.
1938
 */
1939
void scsi_eh_flush_done_q(struct list_head *done_q)
L
Linus Torvalds 已提交
1940
{
1941
	struct scsi_cmnd *scmd, *next;
L
Linus Torvalds 已提交
1942

1943 1944
	list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
		list_del_init(&scmd->eh_entry);
L
Linus Torvalds 已提交
1945
		if (scsi_device_online(scmd->device) &&
1946
		    !scsi_noretry_cmd(scmd) &&
1947
		    (++scmd->retries <= scmd->allowed)) {
L
Linus Torvalds 已提交
1948 1949 1950 1951 1952 1953
			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush"
							  " retry cmd: %p\n",
							  current->comm,
							  scmd));
				scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
		} else {
1954 1955 1956 1957 1958
			/*
			 * If just we got sense for the device (called
			 * scsi_eh_get_sense), scmd->result is already
			 * set, do not set DRIVER_TIMEOUT.
			 */
L
Linus Torvalds 已提交
1959 1960 1961 1962 1963 1964 1965 1966 1967
			if (!scmd->result)
				scmd->result |= (DRIVER_TIMEOUT << 24);
			SCSI_LOG_ERROR_RECOVERY(3, printk("%s: flush finish"
							" cmd: %p\n",
							current->comm, scmd));
			scsi_finish_command(scmd);
		}
	}
}
1968
EXPORT_SYMBOL(scsi_eh_flush_done_q);
L
Linus Torvalds 已提交
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991

/**
 * scsi_unjam_host - Attempt to fix a host which has a cmd that failed.
 * @shost:	Host to unjam.
 *
 * Notes:
 *    When we come in here, we *know* that all commands on the bus have
 *    either completed, failed or timed out.  we also know that no further
 *    commands are being sent to the host, so things are relatively quiet
 *    and we have freedom to fiddle with things as we wish.
 *
 *    This is only the *default* implementation.  it is possible for
 *    individual drivers to supply their own version of this function, and
 *    if the maintainer wishes to do this, it is strongly suggested that
 *    this function be taken as a template and modified.  this function
 *    was designed to correctly handle problems for about 95% of the
 *    different cases out there, and it should always provide at least a
 *    reasonable amount of error recovery.
 *
 *    Any command marked 'failed' or 'timeout' must eventually have
 *    scsi_finish_cmd() called for it.  we do all of the retry stuff
 *    here, so when we restart the host after we return it should have an
 *    empty queue.
1992
 */
L
Linus Torvalds 已提交
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008
static void scsi_unjam_host(struct Scsi_Host *shost)
{
	unsigned long flags;
	LIST_HEAD(eh_work_q);
	LIST_HEAD(eh_done_q);

	spin_lock_irqsave(shost->host_lock, flags);
	list_splice_init(&shost->eh_cmd_q, &eh_work_q);
	spin_unlock_irqrestore(shost->host_lock, flags);

	SCSI_LOG_ERROR_RECOVERY(1, scsi_eh_prt_fail_stats(shost, &eh_work_q));

	if (!scsi_eh_get_sense(&eh_work_q, &eh_done_q))
		if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
			scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);

2009 2010 2011 2012
	spin_lock_irqsave(shost->host_lock, flags);
	if (shost->eh_deadline)
		shost->last_reset = 0;
	spin_unlock_irqrestore(shost->host_lock, flags);
L
Linus Torvalds 已提交
2013 2014 2015 2016
	scsi_eh_flush_done_q(&eh_done_q);
}

/**
2017
 * scsi_error_handler - SCSI error handler thread
L
Linus Torvalds 已提交
2018 2019 2020
 * @data:	Host for which we are running.
 *
 * Notes:
2021 2022
 *    This is the main error handling loop.  This is run as a kernel thread
 *    for every SCSI host and handles all error handling activity.
2023
 */
L
Linus Torvalds 已提交
2024 2025
int scsi_error_handler(void *data)
{
2026
	struct Scsi_Host *shost = data;
L
Linus Torvalds 已提交
2027 2028

	/*
2029 2030 2031
	 * We use TASK_INTERRUPTIBLE so that the thread is not
	 * counted against the load average as a running process.
	 * We never actually get interrupted because kthread_run
2032
	 * disables signal delivery for the created thread.
L
Linus Torvalds 已提交
2033
	 */
2034
	while (!kthread_should_stop()) {
2035
		set_current_state(TASK_INTERRUPTIBLE);
2036
		if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
2037
		    shost->host_failed != shost->host_busy) {
2038
			SCSI_LOG_ERROR_RECOVERY(1,
2039
				printk("scsi_eh_%d: sleeping\n",
2040
					shost->host_no));
2041 2042 2043
			schedule();
			continue;
		}
L
Linus Torvalds 已提交
2044

2045
		__set_current_state(TASK_RUNNING);
2046
		SCSI_LOG_ERROR_RECOVERY(1,
2047 2048 2049
			printk("scsi_eh_%d: waking up %d/%d/%d\n",
			       shost->host_no, shost->host_eh_scheduled,
			       shost->host_failed, shost->host_busy));
L
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2050 2051 2052 2053 2054 2055

		/*
		 * We have a host that is failing for some reason.  Figure out
		 * what we need to do to get it up and online again (if we can).
		 * If we fail, we end up taking the thing offline.
		 */
2056
		if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
2057 2058 2059 2060 2061 2062 2063
			SCSI_LOG_ERROR_RECOVERY(1,
				printk(KERN_ERR "Error handler scsi_eh_%d "
						"unable to autoresume\n",
						shost->host_no));
			continue;
		}

2064 2065
		if (shost->transportt->eh_strategy_handler)
			shost->transportt->eh_strategy_handler(shost);
L
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2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076
		else
			scsi_unjam_host(shost);

		/*
		 * Note - if the above fails completely, the action is to take
		 * individual devices offline and flush the queue of any
		 * outstanding requests that may have been pending.  When we
		 * restart, we restart any I/O to any other devices on the bus
		 * which are still online.
		 */
		scsi_restart_operations(shost);
2077 2078
		if (!shost->eh_noresume)
			scsi_autopm_put_host(shost);
L
Linus Torvalds 已提交
2079
	}
2080 2081
	__set_current_state(TASK_RUNNING);

2082 2083
	SCSI_LOG_ERROR_RECOVERY(1,
		printk("Error handler scsi_eh_%d exiting\n", shost->host_no));
2084
	shost->ehandler = NULL;
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2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113
	return 0;
}

/*
 * Function:    scsi_report_bus_reset()
 *
 * Purpose:     Utility function used by low-level drivers to report that
 *		they have observed a bus reset on the bus being handled.
 *
 * Arguments:   shost       - Host in question
 *		channel     - channel on which reset was observed.
 *
 * Returns:     Nothing
 *
 * Lock status: Host lock must be held.
 *
 * Notes:       This only needs to be called if the reset is one which
 *		originates from an unknown location.  Resets originated
 *		by the mid-level itself don't need to call this, but there
 *		should be no harm.
 *
 *		The main purpose of this is to make sure that a CHECK_CONDITION
 *		is properly treated.
 */
void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
{
	struct scsi_device *sdev;

	__shost_for_each_device(sdev, shost) {
2114 2115
		if (channel == sdev_channel(sdev))
			__scsi_report_device_reset(sdev, NULL);
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2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146
	}
}
EXPORT_SYMBOL(scsi_report_bus_reset);

/*
 * Function:    scsi_report_device_reset()
 *
 * Purpose:     Utility function used by low-level drivers to report that
 *		they have observed a device reset on the device being handled.
 *
 * Arguments:   shost       - Host in question
 *		channel     - channel on which reset was observed
 *		target	    - target on which reset was observed
 *
 * Returns:     Nothing
 *
 * Lock status: Host lock must be held
 *
 * Notes:       This only needs to be called if the reset is one which
 *		originates from an unknown location.  Resets originated
 *		by the mid-level itself don't need to call this, but there
 *		should be no harm.
 *
 *		The main purpose of this is to make sure that a CHECK_CONDITION
 *		is properly treated.
 */
void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
{
	struct scsi_device *sdev;

	__shost_for_each_device(sdev, shost) {
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		if (channel == sdev_channel(sdev) &&
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		    target == sdev_id(sdev))
			__scsi_report_device_reset(sdev, NULL);
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	}
}
EXPORT_SYMBOL(scsi_report_device_reset);

static void
scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
{
}

/*
 * Function:	scsi_reset_provider
 *
 * Purpose:	Send requested reset to a bus or device at any phase.
 *
 * Arguments:	device	- device to send reset to
 *		flag - reset type (see scsi.h)
 *
 * Returns:	SUCCESS/FAILURE.
 *
 * Notes:	This is used by the SCSI Generic driver to provide
 *		Bus/Device reset capability.
 */
int
scsi_reset_provider(struct scsi_device *dev, int flag)
{
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	struct scsi_cmnd *scmd;
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	struct Scsi_Host *shost = dev->host;
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	struct request req;
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	unsigned long flags;
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	int rtn;

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	if (scsi_autopm_get_host(shost) < 0)
		return FAILED;

	scmd = scsi_get_command(dev, GFP_KERNEL);
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	blk_rq_init(NULL, &req);
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	scmd->request = &req;
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	scmd->cmnd = req.cmd;

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	scmd->scsi_done		= scsi_reset_provider_done_command;
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	memset(&scmd->sdb, 0, sizeof(scmd->sdb));
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	scmd->cmd_len			= 0;

	scmd->sc_data_direction		= DMA_BIDIRECTIONAL;

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	spin_lock_irqsave(shost->host_lock, flags);
	shost->tmf_in_progress = 1;
	spin_unlock_irqrestore(shost->host_lock, flags);

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	switch (flag) {
	case SCSI_TRY_RESET_DEVICE:
		rtn = scsi_try_bus_device_reset(scmd);
		if (rtn == SUCCESS)
			break;
		/* FALLTHROUGH */
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	case SCSI_TRY_RESET_TARGET:
		rtn = scsi_try_target_reset(scmd);
		if (rtn == SUCCESS)
			break;
		/* FALLTHROUGH */
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	case SCSI_TRY_RESET_BUS:
		rtn = scsi_try_bus_reset(scmd);
		if (rtn == SUCCESS)
			break;
		/* FALLTHROUGH */
	case SCSI_TRY_RESET_HOST:
		rtn = scsi_try_host_reset(scmd);
		break;
	default:
		rtn = FAILED;
	}

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	spin_lock_irqsave(shost->host_lock, flags);
	shost->tmf_in_progress = 0;
	spin_unlock_irqrestore(shost->host_lock, flags);

	/*
	 * be sure to wake up anyone who was sleeping or had their queue
	 * suspended while we performed the TMF.
	 */
	SCSI_LOG_ERROR_RECOVERY(3,
		printk("%s: waking up host to restart after TMF\n",
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		__func__));
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	wake_up(&shost->host_wait);

	scsi_run_host_queues(shost);

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	scsi_next_command(scmd);
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	scsi_autopm_put_host(shost);
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	return rtn;
}
EXPORT_SYMBOL(scsi_reset_provider);

/**
 * scsi_normalize_sense - normalize main elements from either fixed or
 *			descriptor sense data format into a common format.
 *
 * @sense_buffer:	byte array containing sense data returned by device
 * @sb_len:		number of valid bytes in sense_buffer
 * @sshdr:		pointer to instance of structure that common
 *			elements are written to.
 *
 * Notes:
 *	The "main elements" from sense data are: response_code, sense_key,
 *	asc, ascq and additional_length (only for descriptor format).
 *
 *	Typically this function can be called after a device has
 *	responded to a SCSI command with the CHECK_CONDITION status.
 *
 * Return value:
 *	1 if valid sense data information found, else 0;
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 */
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int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
                         struct scsi_sense_hdr *sshdr)
{
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	if (!sense_buffer || !sb_len)
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		return 0;

	memset(sshdr, 0, sizeof(struct scsi_sense_hdr));

	sshdr->response_code = (sense_buffer[0] & 0x7f);
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	if (!scsi_sense_valid(sshdr))
		return 0;

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	if (sshdr->response_code >= 0x72) {
		/*
		 * descriptor format
		 */
		if (sb_len > 1)
			sshdr->sense_key = (sense_buffer[1] & 0xf);
		if (sb_len > 2)
			sshdr->asc = sense_buffer[2];
		if (sb_len > 3)
			sshdr->ascq = sense_buffer[3];
		if (sb_len > 7)
			sshdr->additional_length = sense_buffer[7];
	} else {
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		/*
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		 * fixed format
		 */
		if (sb_len > 2)
			sshdr->sense_key = (sense_buffer[2] & 0xf);
		if (sb_len > 7) {
			sb_len = (sb_len < (sense_buffer[7] + 8)) ?
					 sb_len : (sense_buffer[7] + 8);
			if (sb_len > 12)
				sshdr->asc = sense_buffer[12];
			if (sb_len > 13)
				sshdr->ascq = sense_buffer[13];
		}
	}

	return 1;
}
EXPORT_SYMBOL(scsi_normalize_sense);

int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
				 struct scsi_sense_hdr *sshdr)
{
	return scsi_normalize_sense(cmd->sense_buffer,
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			SCSI_SENSE_BUFFERSIZE, sshdr);
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}
EXPORT_SYMBOL(scsi_command_normalize_sense);

/**
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 * scsi_sense_desc_find - search for a given descriptor type in	descriptor sense data format.
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 * @sense_buffer:	byte array of descriptor format sense data
 * @sb_len:		number of valid bytes in sense_buffer
 * @desc_type:		value of descriptor type to find
 *			(e.g. 0 -> information)
 *
 * Notes:
 *	only valid when sense data is in descriptor format
 *
 * Return value:
 *	pointer to start of (first) descriptor if found else NULL
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 */
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const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
				int desc_type)
{
	int add_sen_len, add_len, desc_len, k;
	const u8 * descp;

	if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
		return NULL;
	if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
		return NULL;
	add_sen_len = (add_sen_len < (sb_len - 8)) ?
			add_sen_len : (sb_len - 8);
	descp = &sense_buffer[8];
	for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
		descp += desc_len;
		add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
		desc_len = add_len + 2;
		if (descp[0] == desc_type)
			return descp;
		if (add_len < 0) // short descriptor ??
			break;
	}
	return NULL;
}
EXPORT_SYMBOL(scsi_sense_desc_find);

/**
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 * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
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 * @sense_buffer:	byte array of sense data
 * @sb_len:		number of valid bytes in sense_buffer
 * @info_out:		pointer to 64 integer where 8 or 4 byte information
 *			field will be placed if found.
 *
 * Return value:
 *	1 if information field found, 0 if not found.
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 */
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int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
			    u64 * info_out)
{
	int j;
	const u8 * ucp;
	u64 ull;

	if (sb_len < 7)
		return 0;
	switch (sense_buffer[0] & 0x7f) {
	case 0x70:
	case 0x71:
		if (sense_buffer[0] & 0x80) {
			*info_out = (sense_buffer[3] << 24) +
				    (sense_buffer[4] << 16) +
				    (sense_buffer[5] << 8) + sense_buffer[6];
			return 1;
		} else
			return 0;
	case 0x72:
	case 0x73:
		ucp = scsi_sense_desc_find(sense_buffer, sb_len,
					   0 /* info desc */);
		if (ucp && (0xa == ucp[1])) {
			ull = 0;
			for (j = 0; j < 8; ++j) {
				if (j > 0)
					ull <<= 8;
				ull |= ucp[4 + j];
			}
			*info_out = ull;
			return 1;
		} else
			return 0;
	default:
		return 0;
	}
}
EXPORT_SYMBOL(scsi_get_sense_info_fld);
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/**
 * scsi_build_sense_buffer - build sense data in a buffer
 * @desc:	Sense format (non zero == descriptor format,
 * 		0 == fixed format)
 * @buf:	Where to build sense data
 * @key:	Sense key
 * @asc:	Additional sense code
 * @ascq:	Additional sense code qualifier
 *
 **/
void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
{
	if (desc) {
		buf[0] = 0x72;	/* descriptor, current */
		buf[1] = key;
		buf[2] = asc;
		buf[3] = ascq;
		buf[7] = 0;
	} else {
		buf[0] = 0x70;	/* fixed, current */
		buf[2] = key;
		buf[7] = 0xa;
		buf[12] = asc;
		buf[13] = ascq;
	}
}
EXPORT_SYMBOL(scsi_build_sense_buffer);