v4.19.13 snapshot.
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
new file mode 100644
index 0000000..b7a8fdf
--- /dev/null
+++ b/drivers/scsi/scsi_error.c
@@ -0,0 +1,2450 @@
+/*
+ * scsi_error.c Copyright (C) 1997 Eric Youngdale
+ *
+ * SCSI error/timeout handling
+ * Initial versions: Eric Youngdale. Based upon conversations with
+ * Leonard Zubkoff and David Miller at Linux Expo,
+ * 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
+ * minor cleanups.
+ * September 30, 2002 Mike Anderson (andmike@us.ibm.com)
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/gfp.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/interrupt.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_common.h>
+#include <scsi/scsi_transport.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsi_dh.h>
+#include <scsi/scsi_devinfo.h>
+#include <scsi/sg.h>
+
+#include "scsi_priv.h"
+#include "scsi_logging.h"
+#include "scsi_transport_api.h"
+
+#include <trace/events/scsi.h>
+
+#include <asm/unaligned.h>
+
+static void scsi_eh_done(struct scsi_cmnd *scmd);
+
+/*
+ * 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)
+
+static int scsi_eh_try_stu(struct scsi_cmnd *scmd);
+static int scsi_try_to_abort_cmd(struct scsi_host_template *,
+ struct scsi_cmnd *);
+
+void scsi_eh_wakeup(struct Scsi_Host *shost)
+{
+ lockdep_assert_held(shost->host_lock);
+
+ if (scsi_host_busy(shost) == shost->host_failed) {
+ trace_scsi_eh_wakeup(shost);
+ wake_up_process(shost->ehandler);
+ SCSI_LOG_ERROR_RECOVERY(5, shost_printk(KERN_INFO, shost,
+ "Waking error handler thread\n"));
+ }
+}
+
+/**
+ * scsi_schedule_eh - schedule EH for SCSI host
+ * @shost: SCSI host to invoke error handling on.
+ *
+ * Schedule SCSI EH without scmd.
+ */
+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);
+
+static int scsi_host_eh_past_deadline(struct Scsi_Host *shost)
+{
+ if (!shost->last_reset || shost->eh_deadline == -1)
+ return 0;
+
+ /*
+ * 32bit accesses are guaranteed to be atomic
+ * (on all supported architectures), so instead
+ * of using a spinlock we can as well double check
+ * if eh_deadline has been set to 'off' during the
+ * time_before call.
+ */
+ if (time_before(jiffies, shost->last_reset + shost->eh_deadline) &&
+ shost->eh_deadline > -1)
+ return 0;
+
+ return 1;
+}
+
+/**
+ * scmd_eh_abort_handler - Handle command aborts
+ * @work: command to be aborted.
+ *
+ * Note: this function must be called only for a command that has timed out.
+ * Because the block layer marks a request as complete before it calls
+ * scsi_times_out(), a .scsi_done() call from the LLD for a command that has
+ * timed out do not have any effect. Hence it is safe to call
+ * scsi_finish_command() from this function.
+ */
+void
+scmd_eh_abort_handler(struct work_struct *work)
+{
+ struct scsi_cmnd *scmd =
+ container_of(work, struct scsi_cmnd, abort_work.work);
+ struct scsi_device *sdev = scmd->device;
+ int rtn;
+
+ if (scsi_host_eh_past_deadline(sdev->host)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "eh timeout, not aborting\n"));
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "aborting command\n"));
+ rtn = scsi_try_to_abort_cmd(sdev->host->hostt, scmd);
+ if (rtn == SUCCESS) {
+ set_host_byte(scmd, DID_TIME_OUT);
+ if (scsi_host_eh_past_deadline(sdev->host)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "eh timeout, not retrying "
+ "aborted command\n"));
+ } else if (!scsi_noretry_cmd(scmd) &&
+ (++scmd->retries <= scmd->allowed)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_WARNING, scmd,
+ "retry aborted command\n"));
+ scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
+ return;
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_WARNING, scmd,
+ "finish aborted command\n"));
+ scsi_finish_command(scmd);
+ return;
+ }
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "cmd abort %s\n",
+ (rtn == FAST_IO_FAIL) ?
+ "not send" : "failed"));
+ }
+ }
+
+ scsi_eh_scmd_add(scmd);
+}
+
+/**
+ * scsi_abort_command - schedule a command abort
+ * @scmd: scmd to abort.
+ *
+ * We only need to abort commands after a command timeout
+ */
+static int
+scsi_abort_command(struct scsi_cmnd *scmd)
+{
+ struct scsi_device *sdev = scmd->device;
+ struct Scsi_Host *shost = sdev->host;
+ unsigned long flags;
+
+ if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
+ /*
+ * Retry after abort failed, escalate to next level.
+ */
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "previous abort failed\n"));
+ BUG_ON(delayed_work_pending(&scmd->abort_work));
+ return FAILED;
+ }
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (shost->eh_deadline != -1 && !shost->last_reset)
+ shost->last_reset = jiffies;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ scmd->eh_eflags |= SCSI_EH_ABORT_SCHEDULED;
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd, "abort scheduled\n"));
+ queue_delayed_work(shost->tmf_work_q, &scmd->abort_work, HZ / 100);
+ return SUCCESS;
+}
+
+/**
+ * scsi_eh_reset - call into ->eh_action to reset internal counters
+ * @scmd: scmd to run eh on.
+ *
+ * The scsi driver might be carrying internal state about the
+ * devices, so we need to call into the driver to reset the
+ * internal state once the error handler is started.
+ */
+static void scsi_eh_reset(struct scsi_cmnd *scmd)
+{
+ if (!blk_rq_is_passthrough(scmd->request)) {
+ struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
+ if (sdrv->eh_reset)
+ sdrv->eh_reset(scmd);
+ }
+}
+
+static void scsi_eh_inc_host_failed(struct rcu_head *head)
+{
+ struct scsi_cmnd *scmd = container_of(head, typeof(*scmd), rcu);
+ struct Scsi_Host *shost = scmd->device->host;
+ unsigned long flags;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ shost->host_failed++;
+ scsi_eh_wakeup(shost);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+}
+
+/**
+ * scsi_eh_scmd_add - add scsi cmd to error handling.
+ * @scmd: scmd to run eh on.
+ */
+void scsi_eh_scmd_add(struct scsi_cmnd *scmd)
+{
+ struct Scsi_Host *shost = scmd->device->host;
+ unsigned long flags;
+ int ret;
+
+ WARN_ON_ONCE(!shost->ehandler);
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (scsi_host_set_state(shost, SHOST_RECOVERY)) {
+ ret = scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY);
+ WARN_ON_ONCE(ret);
+ }
+ if (shost->eh_deadline != -1 && !shost->last_reset)
+ shost->last_reset = jiffies;
+
+ scsi_eh_reset(scmd);
+ list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ /*
+ * Ensure that all tasks observe the host state change before the
+ * host_failed change.
+ */
+ call_rcu(&scmd->rcu, scsi_eh_inc_host_failed);
+}
+
+/**
+ * scsi_times_out - Timeout function for normal scsi commands.
+ * @req: request that is timing out.
+ *
+ * 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.
+ */
+enum blk_eh_timer_return scsi_times_out(struct request *req)
+{
+ struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
+ enum blk_eh_timer_return rtn = BLK_EH_DONE;
+ struct Scsi_Host *host = scmd->device->host;
+
+ trace_scsi_dispatch_cmd_timeout(scmd);
+ scsi_log_completion(scmd, TIMEOUT_ERROR);
+
+ if (host->eh_deadline != -1 && !host->last_reset)
+ host->last_reset = jiffies;
+
+ if (host->hostt->eh_timed_out)
+ rtn = host->hostt->eh_timed_out(scmd);
+
+ if (rtn == BLK_EH_DONE) {
+ /*
+ * For blk-mq, we must set the request state to complete now
+ * before sending the request to the scsi error handler. This
+ * will prevent a use-after-free in the event the LLD manages
+ * to complete the request before the error handler finishes
+ * processing this timed out request.
+ *
+ * If the request was already completed, then the LLD beat the
+ * time out handler from transferring the request to the scsi
+ * error handler. In that case we can return immediately as no
+ * further action is required.
+ */
+ if (req->q->mq_ops && !blk_mq_mark_complete(req))
+ return rtn;
+ if (scsi_abort_command(scmd) != SUCCESS) {
+ set_host_byte(scmd, DID_TIME_OUT);
+ scsi_eh_scmd_add(scmd);
+ }
+ }
+
+ return rtn;
+}
+
+/**
+ * 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.
+ */
+int scsi_block_when_processing_errors(struct scsi_device *sdev)
+{
+ int online;
+
+ wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
+
+ online = scsi_device_online(sdev);
+
+ SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_INFO, sdev,
+ "%s: rtn: %d\n", __func__, 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.
+ */
+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;
+ if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED)
+ ++cmd_cancel;
+ else
+ ++cmd_failed;
+ }
+ }
+
+ if (cmd_cancel || cmd_failed) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: cmds failed: %d, cancel: %d\n",
+ __func__, cmd_failed,
+ cmd_cancel));
+ cmd_cancel = 0;
+ cmd_failed = 0;
+ ++devices_failed;
+ }
+ }
+
+ SCSI_LOG_ERROR_RECOVERY(2, shost_printk(KERN_INFO, shost,
+ "Total of %d commands on %d"
+ " devices require eh work\n",
+ total_failures, devices_failed));
+}
+#endif
+
+ /**
+ * 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 == 0x29) {
+ evt_type = SDEV_EVT_POWER_ON_RESET_OCCURRED;
+ sdev_printk(KERN_WARNING, sdev,
+ "Power-on or device reset occurred\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 == 0x06) {
+ evt_type = SDEV_EVT_ALUA_STATE_CHANGE_REPORTED;
+ sdev_printk(KERN_WARNING, sdev,
+ "Asymmetric access state 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);
+ }
+}
+
+/**
+ * scsi_check_sense - Examine scsi cmd sense
+ * @scmd: Cmd to have sense checked.
+ *
+ * Return value:
+ * SUCCESS or FAILED or NEEDS_RETRY or ADD_TO_MLQUEUE
+ *
+ * Notes:
+ * When a deferred error is detected the current command has
+ * not been executed and needs retrying.
+ */
+int scsi_check_sense(struct scsi_cmnd *scmd)
+{
+ struct scsi_device *sdev = scmd->device;
+ struct scsi_sense_hdr sshdr;
+
+ if (! scsi_command_normalize_sense(scmd, &sshdr))
+ return FAILED; /* no valid sense data */
+
+ scsi_report_sense(sdev, &sshdr);
+
+ if (scsi_sense_is_deferred(&sshdr))
+ return NEEDS_RETRY;
+
+ if (sdev->handler && sdev->handler->check_sense) {
+ int rc;
+
+ rc = sdev->handler->check_sense(sdev, &sshdr);
+ if (rc != SCSI_RETURN_NOT_HANDLED)
+ return rc;
+ /* handler does not care. Drop down to default handling */
+ }
+
+ 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;
+
+ /*
+ * 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:
+ if (sshdr.asc == 0x10) /* DIF */
+ return SUCCESS;
+
+ if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
+ return ADD_TO_MLQUEUE;
+ if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
+ sdev->sdev_bflags & BLIST_RETRY_ASC_C1)
+ return ADD_TO_MLQUEUE;
+
+ 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) {
+ /*
+ * 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;
+ }
+ }
+ /*
+ * 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;
+ /*
+ * if the device is in the process of becoming ready, we
+ * 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;
+ /*
+ * Pass the UA upwards for a determination in the completion
+ * functions.
+ */
+ return SUCCESS;
+
+ /* these are not supported */
+ case DATA_PROTECT:
+ if (sshdr.asc == 0x27 && sshdr.ascq == 0x07) {
+ /* Thin provisioning hard threshold reached */
+ set_host_byte(scmd, DID_ALLOC_FAILURE);
+ return SUCCESS;
+ }
+ /* FALLTHROUGH */
+ case COPY_ABORTED:
+ case VOLUME_OVERFLOW:
+ case MISCOMPARE:
+ case BLANK_CHECK:
+ set_host_byte(scmd, DID_TARGET_FAILURE);
+ return SUCCESS;
+
+ case MEDIUM_ERROR:
+ if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
+ sshdr.asc == 0x13 || /* AMNF DATA FIELD */
+ sshdr.asc == 0x14) { /* RECORD NOT FOUND */
+ set_host_byte(scmd, DID_MEDIUM_ERROR);
+ return SUCCESS;
+ }
+ return NEEDS_RETRY;
+
+ case HARDWARE_ERROR:
+ if (scmd->device->retry_hwerror)
+ return ADD_TO_MLQUEUE;
+ else
+ set_host_byte(scmd, DID_TARGET_FAILURE);
+ /* FALLTHROUGH */
+
+ case ILLEGAL_REQUEST:
+ if (sshdr.asc == 0x20 || /* Invalid command operation code */
+ sshdr.asc == 0x21 || /* Logical block address out of range */
+ sshdr.asc == 0x22 || /* Invalid function */
+ sshdr.asc == 0x24 || /* Invalid field in cdb */
+ sshdr.asc == 0x26 || /* Parameter value invalid */
+ sshdr.asc == 0x27) { /* Write protected */
+ set_host_byte(scmd, DID_TARGET_FAILURE);
+ }
+ return SUCCESS;
+
+ default:
+ return SUCCESS;
+ }
+}
+EXPORT_SYMBOL_GPL(scsi_check_sense);
+
+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->track_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;
+
+ scsi_change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1);
+ sdev->last_queue_ramp_up = jiffies;
+ }
+}
+
+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->track_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.
+ */
+ scsi_track_queue_full(tmp_sdev, tmp_sdev->queue_depth - 1);
+ }
+}
+
+/**
+ * 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.
+ */
+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:
+ scsi_handle_queue_ramp_up(scmd->device);
+ /* FALLTHROUGH */
+ 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;
+ case RESERVATION_CONFLICT:
+ 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;
+ case QUEUE_FULL:
+ scsi_handle_queue_full(scmd->device);
+ /* fall through */
+ case BUSY:
+ return NEEDS_RETRY;
+ default:
+ return FAILED;
+ }
+ return FAILED;
+}
+
+/**
+ * scsi_eh_done - Completion function for error handling.
+ * @scmd: Cmd that is done.
+ */
+static void scsi_eh_done(struct scsi_cmnd *scmd)
+{
+ struct completion *eh_action;
+
+ SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
+ "%s result: %x\n", __func__, scmd->result));
+
+ eh_action = scmd->device->host->eh_action;
+ if (eh_action)
+ complete(eh_action);
+}
+
+/**
+ * scsi_try_host_reset - ask host adapter to reset itself
+ * @scmd: SCSI cmd to send host reset.
+ */
+static int scsi_try_host_reset(struct scsi_cmnd *scmd)
+{
+ unsigned long flags;
+ int rtn;
+ struct Scsi_Host *host = scmd->device->host;
+ struct scsi_host_template *hostt = host->hostt;
+
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, host, "Snd Host RST\n"));
+
+ if (!hostt->eh_host_reset_handler)
+ return FAILED;
+
+ rtn = hostt->eh_host_reset_handler(scmd);
+
+ if (rtn == SUCCESS) {
+ if (!hostt->skip_settle_delay)
+ ssleep(HOST_RESET_SETTLE_TIME);
+ spin_lock_irqsave(host->host_lock, flags);
+ scsi_report_bus_reset(host, scmd_channel(scmd));
+ spin_unlock_irqrestore(host->host_lock, flags);
+ }
+
+ return rtn;
+}
+
+/**
+ * scsi_try_bus_reset - ask host to perform a bus reset
+ * @scmd: SCSI cmd to send bus reset.
+ */
+static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
+{
+ unsigned long flags;
+ int rtn;
+ struct Scsi_Host *host = scmd->device->host;
+ struct scsi_host_template *hostt = host->hostt;
+
+ SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
+ "%s: Snd Bus RST\n", __func__));
+
+ if (!hostt->eh_bus_reset_handler)
+ return FAILED;
+
+ rtn = hostt->eh_bus_reset_handler(scmd);
+
+ if (rtn == SUCCESS) {
+ if (!hostt->skip_settle_delay)
+ ssleep(BUS_RESET_SETTLE_TIME);
+ spin_lock_irqsave(host->host_lock, flags);
+ scsi_report_bus_reset(host, scmd_channel(scmd));
+ spin_unlock_irqrestore(host->host_lock, flags);
+ }
+
+ return rtn;
+}
+
+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;
+ struct Scsi_Host *host = scmd->device->host;
+ struct scsi_host_template *hostt = host->hostt;
+
+ if (!hostt->eh_target_reset_handler)
+ return FAILED;
+
+ rtn = hostt->eh_target_reset_handler(scmd);
+ if (rtn == SUCCESS) {
+ spin_lock_irqsave(host->host_lock, flags);
+ __starget_for_each_device(scsi_target(scmd->device), NULL,
+ __scsi_report_device_reset);
+ spin_unlock_irqrestore(host->host_lock, flags);
+ }
+
+ return rtn;
+}
+
+/**
+ * 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.
+ */
+static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
+{
+ int rtn;
+ struct scsi_host_template *hostt = scmd->device->host->hostt;
+
+ if (!hostt->eh_device_reset_handler)
+ return FAILED;
+
+ rtn = hostt->eh_device_reset_handler(scmd);
+ if (rtn == SUCCESS)
+ __scsi_report_device_reset(scmd->device, NULL);
+ return rtn;
+}
+
+/**
+ * scsi_try_to_abort_cmd - Ask host to abort a SCSI command
+ * @hostt: SCSI driver host template
+ * @scmd: SCSI cmd used to send a target reset
+ *
+ * Return value:
+ * SUCCESS, FAILED, or FAST_IO_FAIL
+ *
+ * Notes:
+ * SUCCESS does not necessarily indicate that the command
+ * has been aborted; it only indicates that the LLDDs
+ * has cleared all references to that command.
+ * LLDDs should return FAILED only if an abort was required
+ * but could not be executed. LLDDs should return FAST_IO_FAIL
+ * if the device is temporarily unavailable (eg due to a
+ * link down on FibreChannel)
+ */
+static int scsi_try_to_abort_cmd(struct scsi_host_template *hostt,
+ struct scsi_cmnd *scmd)
+{
+ if (!hostt->eh_abort_handler)
+ return FAILED;
+
+ return hostt->eh_abort_handler(scmd);
+}
+
+static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
+{
+ if (scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd) != SUCCESS)
+ if (scsi_try_bus_device_reset(scmd) != SUCCESS)
+ if (scsi_try_target_reset(scmd) != SUCCESS)
+ if (scsi_try_bus_reset(scmd) != SUCCESS)
+ scsi_try_host_reset(scmd);
+}
+
+/**
+ * scsi_eh_prep_cmnd - Save a scsi command info as part of error recovery
+ * @scmd: SCSI command structure to hijack
+ * @ses: structure to save restore information
+ * @cmnd: CDB to send. Can be NULL if no new cmnd is needed
+ * @cmnd_size: size in bytes of @cmnd (must be <= BLK_MAX_CDB)
+ * @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
+ *
+ * This function is used to save a scsi command information before re-execution
+ * 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.
+ */
+void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
+ unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
+{
+ struct scsi_device *sdev = scmd->device;
+
+ /*
+ * 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.
+ */
+ ses->cmd_len = scmd->cmd_len;
+ ses->cmnd = scmd->cmnd;
+ ses->data_direction = scmd->sc_data_direction;
+ ses->sdb = scmd->sdb;
+ ses->next_rq = scmd->request->next_rq;
+ ses->result = scmd->result;
+ ses->underflow = scmd->underflow;
+ ses->prot_op = scmd->prot_op;
+ ses->eh_eflags = scmd->eh_eflags;
+
+ scmd->prot_op = SCSI_PROT_NORMAL;
+ scmd->eh_eflags = 0;
+ scmd->cmnd = ses->eh_cmnd;
+ memset(scmd->cmnd, 0, BLK_MAX_CDB);
+ memset(&scmd->sdb, 0, sizeof(scmd->sdb));
+ scmd->request->next_rq = NULL;
+ scmd->result = 0;
+
+ if (sense_bytes) {
+ scmd->sdb.length = min_t(unsigned, SCSI_SENSE_BUFFERSIZE,
+ sense_bytes);
+ sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
+ scmd->sdb.length);
+ scmd->sdb.table.sgl = &ses->sense_sgl;
+ scmd->sc_data_direction = DMA_FROM_DEVICE;
+ scmd->sdb.table.nents = scmd->sdb.table.orig_nents = 1;
+ scmd->cmnd[0] = REQUEST_SENSE;
+ scmd->cmnd[4] = scmd->sdb.length;
+ scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
+ } else {
+ scmd->sc_data_direction = DMA_NONE;
+ if (cmnd) {
+ BUG_ON(cmnd_size > BLK_MAX_CDB);
+ memcpy(scmd->cmnd, cmnd, cmnd_size);
+ scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
+ }
+ }
+
+ scmd->underflow = 0;
+
+ if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
+ scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
+ (sdev->lun << 5 & 0xe0);
+
+ /*
+ * Zero the sense buffer. The scsi spec mandates that any
+ * untransferred sense data should be interpreted as being zero.
+ */
+ memset(scmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
+}
+EXPORT_SYMBOL(scsi_eh_prep_cmnd);
+
+/**
+ * scsi_eh_restore_cmnd - Restore a scsi command info as part of error recovery
+ * @scmd: SCSI command structure to restore
+ * @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
+ *
+ * Undo any damage done by above scsi_eh_prep_cmnd().
+ */
+void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
+{
+ /*
+ * Restore original data
+ */
+ scmd->cmd_len = ses->cmd_len;
+ scmd->cmnd = ses->cmnd;
+ scmd->sc_data_direction = ses->data_direction;
+ scmd->sdb = ses->sdb;
+ scmd->request->next_rq = ses->next_rq;
+ scmd->result = ses->result;
+ scmd->underflow = ses->underflow;
+ scmd->prot_op = ses->prot_op;
+ scmd->eh_eflags = ses->eh_eflags;
+}
+EXPORT_SYMBOL(scsi_eh_restore_cmnd);
+
+/**
+ * scsi_send_eh_cmnd - submit a scsi command as part of error recovery
+ * @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
+ */
+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);
+ unsigned long timeleft = timeout;
+ struct scsi_eh_save ses;
+ const unsigned long stall_for = msecs_to_jiffies(100);
+ int rtn;
+
+retry:
+ scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
+ shost->eh_action = &done;
+
+ scsi_log_send(scmd);
+ scmd->scsi_done = scsi_eh_done;
+ 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 = FAILED;
+ } else {
+ timeleft = wait_for_completion_timeout(&done, timeout);
+ rtn = SUCCESS;
+ }
+
+ shost->eh_action = NULL;
+
+ scsi_log_completion(scmd, rtn);
+
+ SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
+ "%s timeleft: %ld\n",
+ __func__, timeleft));
+
+ /*
+ * 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)
+ */
+ if (timeleft) {
+ rtn = scsi_eh_completed_normally(scmd);
+ SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
+ "%s: scsi_eh_completed_normally %x\n", __func__, rtn));
+
+ switch (rtn) {
+ case SUCCESS:
+ case NEEDS_RETRY:
+ case FAILED:
+ break;
+ case ADD_TO_MLQUEUE:
+ rtn = NEEDS_RETRY;
+ break;
+ default:
+ rtn = FAILED;
+ break;
+ }
+ } else if (rtn != FAILED) {
+ scsi_abort_eh_cmnd(scmd);
+ rtn = FAILED;
+ }
+
+ scsi_eh_restore_cmnd(scmd, &ses);
+
+ 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.
+ */
+static int scsi_request_sense(struct scsi_cmnd *scmd)
+{
+ return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
+}
+
+static int scsi_eh_action(struct scsi_cmnd *scmd, int rtn)
+{
+ if (!blk_rq_is_passthrough(scmd->request)) {
+ struct scsi_driver *sdrv = scsi_cmd_to_driver(scmd);
+ if (sdrv->eh_action)
+ rtn = sdrv->eh_action(scmd, rtn);
+ }
+ return rtn;
+}
+
+/**
+ * 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,
+ * and that would disturb what we are doing. Thus we really want to
+ * keep a list of pending commands for final completion, and once we
+ * are ready to leave error handling we handle completion for real.
+ */
+void scsi_eh_finish_cmd(struct scsi_cmnd *scmd, struct list_head *done_q)
+{
+ list_move_tail(&scmd->eh_entry, done_q);
+}
+EXPORT_SYMBOL(scsi_eh_finish_cmd);
+
+/**
+ * scsi_eh_get_sense - Get device sense data.
+ * @work_q: Queue of commands to process.
+ * @done_q: Queue of processed commands.
+ *
+ * Description:
+ * See if we need to request sense information. if so, then get it
+ * now, so we have a better idea of what to do.
+ *
+ * Notes:
+ * This has the unfortunate side effect that if a shost adapter does
+ * not automatically request sense information, we end up shutting
+ * 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.
+ */
+int scsi_eh_get_sense(struct list_head *work_q,
+ struct list_head *done_q)
+{
+ struct scsi_cmnd *scmd, *next;
+ struct Scsi_Host *shost;
+ int rtn;
+
+ /*
+ * If SCSI_EH_ABORT_SCHEDULED has been set, it is timeout IO,
+ * should not get sense.
+ */
+ list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
+ if ((scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) ||
+ SCSI_SENSE_VALID(scmd))
+ continue;
+
+ shost = scmd->device->host;
+ if (scsi_host_eh_past_deadline(shost)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "%s: skip request sense, past eh deadline\n",
+ current->comm));
+ break;
+ }
+ if (status_byte(scmd->result) != CHECK_CONDITION)
+ /*
+ * don't request sense if there's no check condition
+ * status because the error we're processing isn't one
+ * that has a sense code (and some devices get
+ * confused by sense requests out of the blue)
+ */
+ continue;
+
+ SCSI_LOG_ERROR_RECOVERY(2, scmd_printk(KERN_INFO, scmd,
+ "%s: requesting sense\n",
+ current->comm));
+ rtn = scsi_request_sense(scmd);
+ if (rtn != SUCCESS)
+ continue;
+
+ SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
+ "sense requested, result %x\n", scmd->result));
+ SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense(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);
+}
+EXPORT_SYMBOL_GPL(scsi_eh_get_sense);
+
+/**
+ * scsi_eh_tur - Send TUR to device.
+ * @scmd: &scsi_cmnd to send TUR
+ *
+ * Return value:
+ * 0 - Device is ready. 1 - Device NOT ready.
+ */
+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:
+ rtn = scsi_send_eh_cmnd(scmd, tur_command, 6,
+ scmd->device->eh_timeout, 0);
+
+ SCSI_LOG_ERROR_RECOVERY(3, scmd_printk(KERN_INFO, scmd,
+ "%s return: %x\n", __func__, rtn));
+
+ switch (rtn) {
+ case NEEDS_RETRY:
+ if (retry_cnt--)
+ goto retry_tur;
+ /*FALLTHRU*/
+ case SUCCESS:
+ return 0;
+ default:
+ return 1;
+ }
+}
+
+/**
+ * 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;
+
+ while (!list_empty(cmd_list)) {
+ scmd = list_entry(cmd_list->next, struct scsi_cmnd, eh_entry);
+ sdev = scmd->device;
+
+ if (!try_stu) {
+ if (scsi_host_eh_past_deadline(sdev->host)) {
+ /* Push items back onto work_q */
+ list_splice_init(cmd_list, work_q);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ sdev_printk(KERN_INFO, sdev,
+ "%s: skip test device, past eh deadline",
+ current->comm));
+ break;
+ }
+ }
+
+ 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) {
+ if (finish_cmds &&
+ (try_stu ||
+ scsi_eh_action(scmd, SUCCESS) == SUCCESS))
+ scsi_eh_finish_cmd(scmd, done_q);
+ else
+ list_move_tail(&scmd->eh_entry, work_q);
+ }
+ }
+ return list_empty(work_q);
+}
+
+/**
+ * scsi_eh_try_stu - Send START_UNIT to device.
+ * @scmd: &scsi_cmnd to send START_UNIT
+ *
+ * Return value:
+ * 0 - Device is ready. 1 - Device NOT ready.
+ */
+static int scsi_eh_try_stu(struct scsi_cmnd *scmd)
+{
+ static unsigned char stu_command[6] = {START_STOP, 0, 0, 0, 1, 0};
+
+ if (scmd->device->allow_restart) {
+ int i, rtn = NEEDS_RETRY;
+
+ for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
+ rtn = scsi_send_eh_cmnd(scmd, stu_command, 6, scmd->device->request_queue->rq_timeout, 0);
+
+ if (rtn == SUCCESS)
+ return 0;
+ }
+
+ return 1;
+}
+
+ /**
+ * scsi_eh_stu - send START_UNIT if needed
+ * @shost: &scsi host being recovered.
+ * @work_q: &list_head for pending commands.
+ * @done_q: &list_head for processed commands.
+ *
+ * Notes:
+ * If commands are failing due to not ready, initializing command required,
+ * try revalidating the device, which will end up sending a start unit.
+ */
+static int scsi_eh_stu(struct Scsi_Host *shost,
+ struct list_head *work_q,
+ struct list_head *done_q)
+{
+ struct scsi_cmnd *scmd, *stu_scmd, *next;
+ struct scsi_device *sdev;
+
+ shost_for_each_device(sdev, shost) {
+ if (scsi_host_eh_past_deadline(shost)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ sdev_printk(KERN_INFO, sdev,
+ "%s: skip START_UNIT, past eh deadline\n",
+ current->comm));
+ break;
+ }
+ 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,
+ sdev_printk(KERN_INFO, sdev,
+ "%s: Sending START_UNIT\n",
+ current->comm));
+
+ if (!scsi_eh_try_stu(stu_scmd)) {
+ if (!scsi_device_online(sdev) ||
+ !scsi_eh_tur(stu_scmd)) {
+ list_for_each_entry_safe(scmd, next,
+ work_q, eh_entry) {
+ if (scmd->device == sdev &&
+ scsi_eh_action(scmd, SUCCESS) == SUCCESS)
+ scsi_eh_finish_cmd(scmd, done_q);
+ }
+ }
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ sdev_printk(KERN_INFO, sdev,
+ "%s: START_UNIT failed\n",
+ current->comm));
+ }
+ }
+
+ return list_empty(work_q);
+}
+
+
+/**
+ * scsi_eh_bus_device_reset - send bdr if needed
+ * @shost: scsi host being recovered.
+ * @work_q: &list_head for pending commands.
+ * @done_q: &list_head for processed commands.
+ *
+ * Notes:
+ * Try a bus device reset. Still, look to see whether we have multiple
+ * 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
+ * a bus_reset instead.
+ */
+static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
+ struct list_head *work_q,
+ struct list_head *done_q)
+{
+ struct scsi_cmnd *scmd, *bdr_scmd, *next;
+ struct scsi_device *sdev;
+ int rtn;
+
+ shost_for_each_device(sdev, shost) {
+ if (scsi_host_eh_past_deadline(shost)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ sdev_printk(KERN_INFO, sdev,
+ "%s: skip BDR, past eh deadline\n",
+ current->comm));
+ break;
+ }
+ 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,
+ sdev_printk(KERN_INFO, sdev,
+ "%s: Sending BDR\n", current->comm));
+ rtn = scsi_try_bus_device_reset(bdr_scmd);
+ if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
+ if (!scsi_device_online(sdev) ||
+ rtn == FAST_IO_FAIL ||
+ !scsi_eh_tur(bdr_scmd)) {
+ list_for_each_entry_safe(scmd, next,
+ work_q, eh_entry) {
+ if (scmd->device == sdev &&
+ scsi_eh_action(scmd, rtn) != FAILED)
+ scsi_eh_finish_cmd(scmd,
+ done_q);
+ }
+ }
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ sdev_printk(KERN_INFO, sdev,
+ "%s: BDR failed\n", current->comm));
+ }
+ }
+
+ return list_empty(work_q);
+}
+
+/**
+ * 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)
+{
+ LIST_HEAD(tmp_list);
+ LIST_HEAD(check_list);
+
+ list_splice_init(work_q, &tmp_list);
+
+ while (!list_empty(&tmp_list)) {
+ struct scsi_cmnd *next, *scmd;
+ int rtn;
+ unsigned int id;
+
+ if (scsi_host_eh_past_deadline(shost)) {
+ /* 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,
+ "%s: Skip target reset, past eh deadline\n",
+ current->comm));
+ return list_empty(work_q);
+ }
+
+ scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
+ id = scmd_id(scmd);
+
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: Sending target reset to target %d\n",
+ current->comm, id));
+ rtn = scsi_try_target_reset(scmd);
+ if (rtn != SUCCESS && rtn != FAST_IO_FAIL)
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: Target reset failed"
+ " target: %d\n",
+ current->comm, id));
+ list_for_each_entry_safe(scmd, next, &tmp_list, eh_entry) {
+ if (scmd_id(scmd) != id)
+ continue;
+
+ if (rtn == SUCCESS)
+ list_move_tail(&scmd->eh_entry, &check_list);
+ else if (rtn == FAST_IO_FAIL)
+ scsi_eh_finish_cmd(scmd, done_q);
+ else
+ /* push back on work queue for further processing */
+ list_move(&scmd->eh_entry, work_q);
+ }
+ }
+
+ return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
+}
+
+/**
+ * scsi_eh_bus_reset - send a bus reset
+ * @shost: &scsi host being recovered.
+ * @work_q: &list_head for pending commands.
+ * @done_q: &list_head for processed commands.
+ */
+static int scsi_eh_bus_reset(struct Scsi_Host *shost,
+ struct list_head *work_q,
+ struct list_head *done_q)
+{
+ struct scsi_cmnd *scmd, *chan_scmd, *next;
+ LIST_HEAD(check_list);
+ unsigned int channel;
+ int rtn;
+
+ /*
+ * 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
+ * the reset.
+ */
+
+ for (channel = 0; channel <= shost->max_channel; channel++) {
+ if (scsi_host_eh_past_deadline(shost)) {
+ list_splice_init(&check_list, work_q);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: skip BRST, past eh deadline\n",
+ current->comm));
+ return list_empty(work_q);
+ }
+
+ chan_scmd = NULL;
+ list_for_each_entry(scmd, work_q, eh_entry) {
+ if (channel == scmd_channel(scmd)) {
+ chan_scmd = scmd;
+ break;
+ /*
+ * FIXME add back in some support for
+ * soft_reset devices.
+ */
+ }
+ }
+
+ if (!chan_scmd)
+ continue;
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: Sending BRST chan: %d\n",
+ current->comm, channel));
+ rtn = scsi_try_bus_reset(chan_scmd);
+ if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
+ list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
+ if (channel == scmd_channel(scmd)) {
+ if (rtn == FAST_IO_FAIL)
+ scsi_eh_finish_cmd(scmd,
+ done_q);
+ else
+ list_move_tail(&scmd->eh_entry,
+ &check_list);
+ }
+ }
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: BRST failed chan: %d\n",
+ current->comm, channel));
+ }
+ }
+ return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
+}
+
+/**
+ * scsi_eh_host_reset - send a host reset
+ * @shost: host to be reset.
+ * @work_q: &list_head for pending commands.
+ * @done_q: &list_head for processed commands.
+ */
+static int scsi_eh_host_reset(struct Scsi_Host *shost,
+ struct list_head *work_q,
+ struct list_head *done_q)
+{
+ struct scsi_cmnd *scmd, *next;
+ LIST_HEAD(check_list);
+ int rtn;
+
+ if (!list_empty(work_q)) {
+ scmd = list_entry(work_q->next,
+ struct scsi_cmnd, eh_entry);
+
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: Sending HRST\n",
+ current->comm));
+
+ rtn = scsi_try_host_reset(scmd);
+ if (rtn == SUCCESS) {
+ list_splice_init(work_q, &check_list);
+ } else if (rtn == FAST_IO_FAIL) {
+ list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
+ scsi_eh_finish_cmd(scmd, done_q);
+ }
+ } else {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost,
+ "%s: HRST failed\n",
+ current->comm));
+ }
+ }
+ return scsi_eh_test_devices(&check_list, work_q, done_q, 1);
+}
+
+/**
+ * scsi_eh_offline_sdevs - offline scsi devices that fail to recover
+ * @work_q: &list_head for pending commands.
+ * @done_q: &list_head for processed commands.
+ */
+static void scsi_eh_offline_sdevs(struct list_head *work_q,
+ struct list_head *done_q)
+{
+ struct scsi_cmnd *scmd, *next;
+ struct scsi_device *sdev;
+
+ list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
+ sdev_printk(KERN_INFO, scmd->device, "Device offlined - "
+ "not ready after error recovery\n");
+ sdev = scmd->device;
+
+ mutex_lock(&sdev->state_mutex);
+ scsi_device_set_state(sdev, SDEV_OFFLINE);
+ mutex_unlock(&sdev->state_mutex);
+
+ scsi_eh_finish_cmd(scmd, done_q);
+ }
+ return;
+}
+
+/**
+ * scsi_noretry_cmd - determine 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_TIME_OUT:
+ goto check_type;
+ case DID_BUS_BUSY:
+ return (scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT);
+ case DID_PARITY:
+ return (scmd->request->cmd_flags & REQ_FAILFAST_DEV);
+ case DID_ERROR:
+ if (msg_byte(scmd->result) == COMMAND_COMPLETE &&
+ status_byte(scmd->result) == RESERVATION_CONFLICT)
+ return 0;
+ /* fall through */
+ case DID_SOFT_ERROR:
+ return (scmd->request->cmd_flags & REQ_FAILFAST_DRIVER);
+ }
+
+ if (status_byte(scmd->result) != CHECK_CONDITION)
+ return 0;
+
+check_type:
+ /*
+ * assume caller has checked sense and determined
+ * the check condition was retryable.
+ */
+ if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
+ blk_rq_is_passthrough(scmd->request))
+ return 1;
+ else
+ return 0;
+}
+
+/**
+ * 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.
+ */
+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, scmd_printk(KERN_INFO, scmd,
+ "%s: device offline - report as SUCCESS\n", __func__));
+ 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_ABORT:
+ if (scmd->eh_eflags & SCSI_EH_ABORT_SCHEDULED) {
+ set_host_byte(scmd, DID_TIME_OUT);
+ return SUCCESS;
+ }
+ /* FALLTHROUGH */
+ case DID_NO_CONNECT:
+ case DID_BAD_TARGET:
+ /*
+ * 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;
+ case DID_SOFT_ERROR:
+ /*
+ * when the low level driver returns did_soft_error,
+ * it is responsible for keeping an internal retry counter
+ * in order to avoid endless loops (db)
+ */
+ goto maybe_retry;
+ case DID_IMM_RETRY:
+ return NEEDS_RETRY;
+
+ case DID_REQUEUE:
+ return ADD_TO_MLQUEUE;
+ 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
+ * based on its timers and recovery capablilities if
+ * there are enough retries.
+ */
+ goto maybe_retry;
+ 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;
+ 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:
+ scsi_handle_queue_full(scmd->device);
+ /*
+ * the case of trying to send too many commands to a
+ * tagged queueing device.
+ */
+ /* FALLTHROUGH */
+ 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:
+ if (scmd->cmnd[0] == REPORT_LUNS)
+ scmd->device->sdev_target->expecting_lun_change = 0;
+ scsi_handle_queue_ramp_up(scmd->device);
+ /* FALLTHROUGH */
+ case COMMAND_TERMINATED:
+ return SUCCESS;
+ case TASK_ABORTED:
+ goto maybe_retry;
+ 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:
+ sdev_printk(KERN_INFO, scmd->device,
+ "reservation conflict\n");
+ set_host_byte(scmd, DID_NEXUS_FAILURE);
+ 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) */
+ if ((++scmd->retries) <= scmd->allowed
+ && !scsi_noretry_cmd(scmd)) {
+ return NEEDS_RETRY;
+ } else {
+ /*
+ * no more retries - report this one back to upper level.
+ */
+ return SUCCESS;
+ }
+}
+
+static void eh_lock_door_done(struct request *req, blk_status_t status)
+{
+ __blk_put_request(req->q, req);
+}
+
+/**
+ * scsi_eh_lock_door - Prevent medium removal for the specified device
+ * @sdev: SCSI device to prevent medium removal
+ *
+ * Locking:
+ * We must be called from process context.
+ *
+ * Notes:
+ * We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
+ * head of the devices request queue, and continue.
+ */
+static void scsi_eh_lock_door(struct scsi_device *sdev)
+{
+ struct request *req;
+ struct scsi_request *rq;
+
+ req = blk_get_request(sdev->request_queue, REQ_OP_SCSI_IN, 0);
+ if (IS_ERR(req))
+ return;
+ rq = scsi_req(req);
+
+ rq->cmd[0] = ALLOW_MEDIUM_REMOVAL;
+ rq->cmd[1] = 0;
+ rq->cmd[2] = 0;
+ rq->cmd[3] = 0;
+ rq->cmd[4] = SCSI_REMOVAL_PREVENT;
+ rq->cmd[5] = 0;
+ rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
+
+ req->rq_flags |= RQF_QUIET;
+ req->timeout = 10 * HZ;
+ rq->retries = 5;
+
+ blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
+}
+
+/**
+ * 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.
+ */
+static void scsi_restart_operations(struct Scsi_Host *shost)
+{
+ struct scsi_device *sdev;
+ unsigned long flags;
+
+ /*
+ * 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->was_reset && sdev->locked) {
+ scsi_eh_lock_door(sdev);
+ sdev->was_reset = 0;
+ }
+ }
+
+ /*
+ * 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.
+ */
+ SCSI_LOG_ERROR_RECOVERY(3,
+ shost_printk(KERN_INFO, shost, "waking up host to restart\n"));
+
+ 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);
+
+ 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);
+
+ /*
+ * 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);
+}
+
+/**
+ * scsi_eh_ready_devs - check device ready state and recover if not.
+ * @shost: host to be recovered.
+ * @work_q: &list_head for pending commands.
+ * @done_q: &list_head for processed commands.
+ */
+void scsi_eh_ready_devs(struct Scsi_Host *shost,
+ struct list_head *work_q,
+ struct list_head *done_q)
+{
+ if (!scsi_eh_stu(shost, work_q, done_q))
+ if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
+ 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(shost, work_q, done_q))
+ scsi_eh_offline_sdevs(work_q,
+ done_q);
+}
+EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
+
+/**
+ * scsi_eh_flush_done_q - finish processed commands or retry them.
+ * @done_q: list_head of processed commands.
+ */
+void scsi_eh_flush_done_q(struct list_head *done_q)
+{
+ struct scsi_cmnd *scmd, *next;
+
+ list_for_each_entry_safe(scmd, next, done_q, eh_entry) {
+ list_del_init(&scmd->eh_entry);
+ if (scsi_device_online(scmd->device) &&
+ !scsi_noretry_cmd(scmd) &&
+ (++scmd->retries <= scmd->allowed)) {
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "%s: flush retry cmd\n",
+ current->comm));
+ scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
+ } else {
+ /*
+ * If just we got sense for the device (called
+ * scsi_eh_get_sense), scmd->result is already
+ * set, do not set DRIVER_TIMEOUT.
+ */
+ if (!scmd->result)
+ scmd->result |= (DRIVER_TIMEOUT << 24);
+ SCSI_LOG_ERROR_RECOVERY(3,
+ scmd_printk(KERN_INFO, scmd,
+ "%s: flush finish cmd\n",
+ current->comm));
+ scsi_finish_command(scmd);
+ }
+ }
+}
+EXPORT_SYMBOL(scsi_eh_flush_done_q);
+
+/**
+ * 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.
+ */
+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))
+ scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ if (shost->eh_deadline != -1)
+ shost->last_reset = 0;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+ scsi_eh_flush_done_q(&eh_done_q);
+}
+
+/**
+ * scsi_error_handler - SCSI error handler thread
+ * @data: Host for which we are running.
+ *
+ * Notes:
+ * This is the main error handling loop. This is run as a kernel thread
+ * for every SCSI host and handles all error handling activity.
+ */
+int scsi_error_handler(void *data)
+{
+ struct Scsi_Host *shost = data;
+
+ /*
+ * 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
+ * disables signal delivery for the created thread.
+ */
+ while (true) {
+ /*
+ * The sequence in kthread_stop() sets the stop flag first
+ * then wakes the process. To avoid missed wakeups, the task
+ * should always be in a non running state before the stop
+ * flag is checked
+ */
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (kthread_should_stop())
+ break;
+
+ if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
+ shost->host_failed != scsi_host_busy(shost)) {
+ SCSI_LOG_ERROR_RECOVERY(1,
+ shost_printk(KERN_INFO, shost,
+ "scsi_eh_%d: sleeping\n",
+ shost->host_no));
+ schedule();
+ continue;
+ }
+
+ __set_current_state(TASK_RUNNING);
+ SCSI_LOG_ERROR_RECOVERY(1,
+ shost_printk(KERN_INFO, shost,
+ "scsi_eh_%d: waking up %d/%d/%d\n",
+ shost->host_no, shost->host_eh_scheduled,
+ shost->host_failed,
+ scsi_host_busy(shost)));
+
+ /*
+ * 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.
+ */
+ if (!shost->eh_noresume && scsi_autopm_get_host(shost) != 0) {
+ SCSI_LOG_ERROR_RECOVERY(1,
+ shost_printk(KERN_ERR, shost,
+ "scsi_eh_%d: unable to autoresume\n",
+ shost->host_no));
+ continue;
+ }
+
+ if (shost->transportt->eh_strategy_handler)
+ shost->transportt->eh_strategy_handler(shost);
+ else
+ scsi_unjam_host(shost);
+
+ /* All scmds have been handled */
+ shost->host_failed = 0;
+
+ /*
+ * 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);
+ if (!shost->eh_noresume)
+ scsi_autopm_put_host(shost);
+ }
+ __set_current_state(TASK_RUNNING);
+
+ SCSI_LOG_ERROR_RECOVERY(1,
+ shost_printk(KERN_INFO, shost,
+ "Error handler scsi_eh_%d exiting\n",
+ shost->host_no));
+ shost->ehandler = NULL;
+ 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) {
+ if (channel == sdev_channel(sdev))
+ __scsi_report_device_reset(sdev, NULL);
+ }
+}
+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) {
+ if (channel == sdev_channel(sdev) &&
+ target == sdev_id(sdev))
+ __scsi_report_device_reset(sdev, NULL);
+ }
+}
+EXPORT_SYMBOL(scsi_report_device_reset);
+
+static void
+scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
+{
+}
+
+/**
+ * scsi_ioctl_reset: explicitly reset a host/bus/target/device
+ * @dev: scsi_device to operate on
+ * @arg: reset type (see sg.h)
+ */
+int
+scsi_ioctl_reset(struct scsi_device *dev, int __user *arg)
+{
+ struct scsi_cmnd *scmd;
+ struct Scsi_Host *shost = dev->host;
+ struct request *rq;
+ unsigned long flags;
+ int error = 0, rtn, val;
+
+ if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
+ return -EACCES;
+
+ error = get_user(val, arg);
+ if (error)
+ return error;
+
+ if (scsi_autopm_get_host(shost) < 0)
+ return -EIO;
+
+ error = -EIO;
+ rq = kzalloc(sizeof(struct request) + sizeof(struct scsi_cmnd) +
+ shost->hostt->cmd_size, GFP_KERNEL);
+ if (!rq)
+ goto out_put_autopm_host;
+ blk_rq_init(NULL, rq);
+
+ scmd = (struct scsi_cmnd *)(rq + 1);
+ scsi_init_command(dev, scmd);
+ scmd->request = rq;
+ scmd->cmnd = scsi_req(rq)->cmd;
+
+ scmd->scsi_done = scsi_reset_provider_done_command;
+ memset(&scmd->sdb, 0, sizeof(scmd->sdb));
+
+ scmd->cmd_len = 0;
+
+ scmd->sc_data_direction = DMA_BIDIRECTIONAL;
+
+ spin_lock_irqsave(shost->host_lock, flags);
+ shost->tmf_in_progress = 1;
+ spin_unlock_irqrestore(shost->host_lock, flags);
+
+ switch (val & ~SG_SCSI_RESET_NO_ESCALATE) {
+ case SG_SCSI_RESET_NOTHING:
+ rtn = SUCCESS;
+ break;
+ case SG_SCSI_RESET_DEVICE:
+ rtn = scsi_try_bus_device_reset(scmd);
+ if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
+ break;
+ /* FALLTHROUGH */
+ case SG_SCSI_RESET_TARGET:
+ rtn = scsi_try_target_reset(scmd);
+ if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
+ break;
+ /* FALLTHROUGH */
+ case SG_SCSI_RESET_BUS:
+ rtn = scsi_try_bus_reset(scmd);
+ if (rtn == SUCCESS || (val & SG_SCSI_RESET_NO_ESCALATE))
+ break;
+ /* FALLTHROUGH */
+ case SG_SCSI_RESET_HOST:
+ rtn = scsi_try_host_reset(scmd);
+ if (rtn == SUCCESS)
+ break;
+ /* FALLTHROUGH */
+ default:
+ rtn = FAILED;
+ break;
+ }
+
+ error = (rtn == SUCCESS) ? 0 : -EIO;
+
+ 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,
+ shost_printk(KERN_INFO, shost,
+ "waking up host to restart after TMF\n"));
+
+ wake_up(&shost->host_wait);
+ scsi_run_host_queues(shost);
+
+ scsi_put_command(scmd);
+ kfree(rq);
+
+out_put_autopm_host:
+ scsi_autopm_put_host(shost);
+ return error;
+}
+EXPORT_SYMBOL(scsi_ioctl_reset);
+
+bool scsi_command_normalize_sense(const struct scsi_cmnd *cmd,
+ struct scsi_sense_hdr *sshdr)
+{
+ return scsi_normalize_sense(cmd->sense_buffer,
+ SCSI_SENSE_BUFFERSIZE, sshdr);
+}
+EXPORT_SYMBOL(scsi_command_normalize_sense);
+
+/**
+ * scsi_get_sense_info_fld - get information field from sense data (either fixed or descriptor format)
+ * @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:
+ * true if information field found, false if not found.
+ */
+bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
+ u64 *info_out)
+{
+ const u8 * ucp;
+
+ if (sb_len < 7)
+ return false;
+ switch (sense_buffer[0] & 0x7f) {
+ case 0x70:
+ case 0x71:
+ if (sense_buffer[0] & 0x80) {
+ *info_out = get_unaligned_be32(&sense_buffer[3]);
+ return true;
+ }
+ return false;
+ case 0x72:
+ case 0x73:
+ ucp = scsi_sense_desc_find(sense_buffer, sb_len,
+ 0 /* info desc */);
+ if (ucp && (0xa == ucp[1])) {
+ *info_out = get_unaligned_be64(&ucp[4]);
+ return true;
+ }
+ return false;
+ default:
+ return false;
+ }
+}
+EXPORT_SYMBOL(scsi_get_sense_info_fld);