Google Git
Sign in
android-kvm / linux / bf5e3a30f777b6e763f6a46c10e1250c20237e97 / . / drivers / scsi / scsi_error.c
blob: 612489afe8d2467965759c80562562e26919f704 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* 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>
/*
* 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 enum scsi_disposition scsi_try_to_abort_cmd(const struct scsi_host_template *,
struct scsi_cmnd *);
void scsi_eh_wakeup(struct Scsi_Host *shost, unsigned int busy)
{
lockdep_assert_held(shost->host_lock);
if (busy == 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, scsi_host_busy(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;
}
static bool scsi_cmd_retry_allowed(struct scsi_cmnd *cmd)
{
if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
return true;
return ++cmd->retries <= cmd->allowed;
}
static bool scsi_eh_should_retry_cmd(struct scsi_cmnd *cmd)
{
struct scsi_device *sdev = cmd->device;
struct Scsi_Host *host = sdev->host;
if (host->hostt->eh_should_retry_cmd)
return host->hostt->eh_should_retry_cmd(cmd);
return true;
}
/**
* 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_timeout(), 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;
struct Scsi_Host *shost = sdev->host;
enum scsi_disposition rtn;
unsigned long flags;
if (scsi_host_eh_past_deadline(shost)) {
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"eh timeout, not aborting\n"));
goto out;
}
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"aborting command\n"));
rtn = scsi_try_to_abort_cmd(shost->hostt, scmd);
if (rtn != SUCCESS) {
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"cmd abort %s\n",
(rtn == FAST_IO_FAIL) ?
"not send" : "failed"));
goto out;
}
set_host_byte(scmd, DID_TIME_OUT);
if (scsi_host_eh_past_deadline(shost)) {
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_INFO, scmd,
"eh timeout, not retrying "
"aborted command\n"));
goto out;
}
spin_lock_irqsave(shost->host_lock, flags);
list_del_init(&scmd->eh_entry);
/*
* If the abort succeeds, and there is no further
* EH action, clear the ->last_reset time.
*/
if (list_empty(&shost->eh_abort_list) &&
list_empty(&shost->eh_cmd_q))
if (shost->eh_deadline != -1)
shost->last_reset = 0;
spin_unlock_irqrestore(shost->host_lock, flags);
if (!scsi_noretry_cmd(scmd) &&
scsi_cmd_retry_allowed(scmd) &&
scsi_eh_should_retry_cmd(scmd)) {
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_WARNING, scmd,
"retry aborted command\n"));
scsi_queue_insert(scmd, SCSI_MLQUEUE_EH_RETRY);
} else {
SCSI_LOG_ERROR_RECOVERY(3,
scmd_printk(KERN_WARNING, scmd,
"finish aborted command\n"));
scsi_finish_command(scmd);
}
return;
out:
spin_lock_irqsave(shost->host_lock, flags);
list_del_init(&scmd->eh_entry);
spin_unlock_irqrestore(shost->host_lock, flags);
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 (!shost->hostt->eh_abort_handler) {
/* No abort handler, fail command directly */
return FAILED;
}
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;
BUG_ON(!list_empty(&scmd->eh_entry));
list_add_tail(&scmd->eh_entry, &shost->eh_abort_list);
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(scsi_cmd_to_rq(scmd))) {
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 int busy = scsi_host_busy(shost);
unsigned long flags;
spin_lock_irqsave(shost->host_lock, flags);
shost->host_failed++;
scsi_eh_wakeup(shost, busy);
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);
WARN_ON_ONCE(!test_bit(SCMD_STATE_INFLIGHT, &scmd->state));
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_hurry(&scmd->rcu, scsi_eh_inc_host_failed);
}
/**
* scsi_timeout - 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_timeout(struct request *req)
{
struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(req);
struct Scsi_Host *host = scmd->device->host;
trace_scsi_dispatch_cmd_timeout(scmd);
scsi_log_completion(scmd, TIMEOUT_ERROR);
atomic_inc(&scmd->device->iotmo_cnt);
if (host->eh_deadline != -1 && !host->last_reset)
host->last_reset = jiffies;
if (host->hostt->eh_timed_out) {
switch (host->hostt->eh_timed_out(scmd)) {
case SCSI_EH_DONE:
return BLK_EH_DONE;
case SCSI_EH_RESET_TIMER:
return BLK_EH_RESET_TIMER;
case SCSI_EH_NOT_HANDLED:
break;
}
}
/*
* If scsi_done() has already set SCMD_STATE_COMPLETE, do not modify
* *scmd.
*/
if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
return BLK_EH_DONE;
atomic_inc(&scmd->device->iodone_cnt);
if (scsi_abort_command(scmd) != SUCCESS) {
set_host_byte(scmd, DID_TIME_OUT);
scsi_eh_scmd_add(scmd);
}
return BLK_EH_DONE;
}
/**
* 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);
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,
"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,
"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;
/*
* Do not print message if it is an expected side-effect
* of runtime PM.
*/
if (!sdev->silence_suspend)
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);
}
}
static inline void set_scsi_ml_byte(struct scsi_cmnd *cmd, u8 status)
{
cmd->result = (cmd->result & 0xffff00ff) | (status << 8);
}
/**
* 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.
*/
enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
{
struct request *req = scsi_cmd_to_rq(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) {
enum scsi_disposition 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->submitter != SUBMITTED_BY_SCSI_ERROR_HANDLER)
/*
* 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;
/*
* Check aborts due to command duration limit policy:
* ABORTED COMMAND additional sense code with the
* COMMAND TIMEOUT BEFORE PROCESSING or
* COMMAND TIMEOUT DURING PROCESSING or
* COMMAND TIMEOUT DURING PROCESSING DUE TO ERROR RECOVERY
* additional sense code qualifiers.
*/
if (sshdr.asc == 0x2e &&
sshdr.ascq >= 0x01 && sshdr.ascq <= 0x03) {
set_scsi_ml_byte(scmd, SCSIML_STAT_DL_TIMEOUT);
req->cmd_flags |= REQ_FAILFAST_DEV;
req->rq_flags |= RQF_QUIET;
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_scsi_ml_byte(scmd, SCSIML_STAT_NOSPC);
return SUCCESS;
}
fallthrough;
case COPY_ABORTED:
case VOLUME_OVERFLOW:
case MISCOMPARE:
case BLANK_CHECK:
set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_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_scsi_ml_byte(scmd, SCSIML_STAT_MED_ERROR);
return SUCCESS;
}
return NEEDS_RETRY;
case HARDWARE_ERROR:
if (scmd->device->retry_hwerror)
return ADD_TO_MLQUEUE;
else
set_scsi_ml_byte(scmd, SCSIML_STAT_TGT_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_scsi_ml_byte(scmd, SCSIML_STAT_TGT_FAILURE);
}
return SUCCESS;
case COMPLETED:
if (sshdr.asc == 0x55 && sshdr.ascq == 0x0a) {
set_scsi_ml_byte(scmd, SCSIML_STAT_DL_TIMEOUT);
req->cmd_flags |= REQ_FAILFAST_DEV;
req->rq_flags |= RQF_QUIET;
}
return SUCCESS;
default:
return SUCCESS;
}
}
EXPORT_SYMBOL_GPL(scsi_check_sense);
static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
{
const 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)
{
const 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 enum scsi_disposition 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;
/*
* now, check the status byte to see if this indicates
* anything special.
*/
switch (get_status_byte(scmd)) {
case SAM_STAT_GOOD:
scsi_handle_queue_ramp_up(scmd->device);
if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd))
/*
* If we have sense data, call scsi_check_sense() in
* order to set the correct SCSI ML byte (if any).
* No point in checking the return value, since the
* command has already completed successfully.
*/
scsi_check_sense(scmd);
fallthrough;
case SAM_STAT_COMMAND_TERMINATED:
return SUCCESS;
case SAM_STAT_CHECK_CONDITION:
return scsi_check_sense(scmd);
case SAM_STAT_CONDITION_MET:
case SAM_STAT_INTERMEDIATE:
case SAM_STAT_INTERMEDIATE_CONDITION_MET:
/*
* who knows? FIXME(eric)
*/
return SUCCESS;
case SAM_STAT_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 SAM_STAT_TASK_SET_FULL:
scsi_handle_queue_full(scmd->device);
fallthrough;
case SAM_STAT_BUSY:
return NEEDS_RETRY;
default:
return FAILED;
}
return FAILED;
}
/**
* scsi_eh_done - Completion function for error handling.
* @scmd: Cmd that is done.
*/
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 enum scsi_disposition scsi_try_host_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
enum scsi_disposition rtn;
struct Scsi_Host *host = scmd->device->host;
const 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 enum scsi_disposition scsi_try_bus_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
enum scsi_disposition rtn;
struct Scsi_Host *host = scmd->device->host;
const 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 enum scsi_disposition scsi_try_target_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
enum scsi_disposition rtn;
struct Scsi_Host *host = scmd->device->host;
const 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 enum scsi_disposition scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
{
enum scsi_disposition rtn;
const 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 enum scsi_disposition
scsi_try_to_abort_cmd(const 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 <= MAX_COMMAND_SIZE)
* @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->data_direction = scmd->sc_data_direction;
ses->sdb = scmd->sdb;
ses->result = scmd->result;
ses->resid_len = scmd->resid_len;
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;
memcpy(ses->cmnd, scmd->cmnd, sizeof(ses->cmnd));
memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
scmd->result = 0;
scmd->resid_len = 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 > sizeof(scmd->cmnd));
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;
memcpy(scmd->cmnd, ses->cmnd, sizeof(ses->cmnd));
scmd->sc_data_direction = ses->data_direction;
scmd->sdb = ses->sdb;
scmd->result = ses->result;
scmd->resid_len = ses->resid_len;
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 enum scsi_disposition 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, delay;
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->submitter = SUBMITTED_BY_SCSI_ERROR_HANDLER;
scmd->flags |= SCMD_LAST;
/*
* Lock sdev->state_mutex to avoid that scsi_device_quiesce() can
* change the SCSI device state after we have examined it and before
* .queuecommand() is called.
*/
mutex_lock(&sdev->state_mutex);
while (sdev->sdev_state == SDEV_BLOCK && timeleft > 0) {
mutex_unlock(&sdev->state_mutex);
SCSI_LOG_ERROR_RECOVERY(5, sdev_printk(KERN_DEBUG, sdev,
"%s: state %d <> %d\n", __func__, sdev->sdev_state,
SDEV_BLOCK));
delay = min(timeleft, stall_for);
timeleft -= delay;
msleep(jiffies_to_msecs(delay));
mutex_lock(&sdev->state_mutex);
}
if (sdev->sdev_state != SDEV_BLOCK)
rtn = shost->hostt->queuecommand(shost, scmd);
else
rtn = FAILED;
mutex_unlock(&sdev->state_mutex);
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 enum scsi_disposition scsi_request_sense(struct scsi_cmnd *scmd)
{
return scsi_send_eh_cmnd(scmd, NULL, 0, scmd->device->eh_timeout, ~0);
}
static enum scsi_disposition
scsi_eh_action(struct scsi_cmnd *scmd, enum scsi_disposition rtn)
{
if (!blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
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;
enum scsi_disposition 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 (!scsi_status_is_check_condition(scmd->result))
/*
* 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. If the user
* has requested infinite retries, we also want to
* finish this command, so force completion by setting
* retries and allowed to the same value.
*/
if (scmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
scmd->retries = scmd->allowed = 1;
else
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;
enum scsi_disposition 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;
fallthrough;
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;
enum scsi_disposition rtn = NEEDS_RETRY;
for (i = 0; rtn == NEEDS_RETRY && i < 2; i++)
rtn = scsi_send_eh_cmnd(scmd, stu_command, 6,
scmd->device->eh_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));
scsi_device_put(sdev);
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;
enum scsi_disposition 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));
scsi_device_put(sdev);
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;
enum scsi_disposition 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;
enum scsi_disposition 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);
enum scsi_disposition 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.
*/
bool scsi_noretry_cmd(struct scsi_cmnd *scmd)
{
struct request *req = scsi_cmd_to_rq(scmd);
switch (host_byte(scmd->result)) {
case DID_OK:
break;
case DID_TIME_OUT:
goto check_type;
case DID_BUS_BUSY:
return !!(req->cmd_flags & REQ_FAILFAST_TRANSPORT);
case DID_PARITY:
return !!(req->cmd_flags & REQ_FAILFAST_DEV);
case DID_ERROR:
if (get_status_byte(scmd) == SAM_STAT_RESERVATION_CONFLICT)
return false;
fallthrough;
case DID_SOFT_ERROR:
return !!(req->cmd_flags & REQ_FAILFAST_DRIVER);
}
/* Never retry commands aborted due to a duration limit timeout */
if (scsi_ml_byte(scmd->result) == SCSIML_STAT_DL_TIMEOUT)
return true;
if (!scsi_status_is_check_condition(scmd->result))
return false;
check_type:
/*
* assume caller has checked sense and determined
* the check condition was retryable.
*/
if (req->cmd_flags & REQ_FAILFAST_DEV || blk_rq_is_passthrough(req))
return true;
return false;
}
/**
* 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.
*/
enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
{
enum scsi_disposition 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_TRANSPORT_MARGINAL:
/*
* caller has decided not to do retries on
* abort success, so send IO directly upwards
*/
return SUCCESS;
case DID_ERROR:
if (get_status_byte(scmd) == SAM_STAT_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;
}
/*
* check the status byte to see if this indicates anything special.
*/
switch (get_status_byte(scmd)) {
case SAM_STAT_TASK_SET_FULL:
scsi_handle_queue_full(scmd->device);
/*
* the case of trying to send too many commands to a
* tagged queueing device.
*/
fallthrough;
case SAM_STAT_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 SAM_STAT_GOOD:
if (scmd->cmnd[0] == REPORT_LUNS)
scmd->device->sdev_target->expecting_lun_change = 0;
scsi_handle_queue_ramp_up(scmd->device);
if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd))
/*
* If we have sense data, call scsi_check_sense() in
* order to set the correct SCSI ML byte (if any).
* No point in checking the return value, since the
* command has already completed successfully.
*/
scsi_check_sense(scmd);
fallthrough;
case SAM_STAT_COMMAND_TERMINATED:
return SUCCESS;
case SAM_STAT_TASK_ABORTED:
goto maybe_retry;
case SAM_STAT_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 SAM_STAT_CONDITION_MET:
case SAM_STAT_INTERMEDIATE:
case SAM_STAT_INTERMEDIATE_CONDITION_MET:
case SAM_STAT_ACA_ACTIVE:
/*
* who knows? FIXME(eric)
*/
return SUCCESS;
case SAM_STAT_RESERVATION_CONFLICT:
sdev_printk(KERN_INFO, scmd->device,
"reservation conflict\n");
set_scsi_ml_byte(scmd, SCSIML_STAT_RESV_CONFLICT);
return SUCCESS; /* causes immediate i/o error */
}
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 (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
return NEEDS_RETRY;
} else {
/*
* no more retries - report this one back to upper level.
*/
return SUCCESS;
}
}
static enum rq_end_io_ret eh_lock_door_done(struct request *req,
blk_status_t status)
{
blk_mq_free_request(req);
return RQ_END_IO_NONE;
}
/**
* 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 scsi_cmnd *scmd;
struct request *req;
req = scsi_alloc_request(sdev->request_queue, REQ_OP_DRV_IN, 0);
if (IS_ERR(req))
return;
scmd = blk_mq_rq_to_pdu(req);
scmd->cmnd[0] = ALLOW_MEDIUM_REMOVAL;
scmd->cmnd[1] = 0;
scmd->cmnd[2] = 0;
scmd->cmnd[3] = 0;
scmd->cmnd[4] = SCSI_REMOVAL_PREVENT;
scmd->cmnd[5] = 0;
scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
scmd->allowed = 5;
req->rq_flags |= RQF_QUIET;
req->timeout = 10 * HZ;
req->end_io = eh_lock_door_done;
blk_execute_rq_nowait(req, true);
}
/**
* 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) {
struct scsi_device *sdev = scmd->device;
list_del_init(&scmd->eh_entry);
if (scsi_device_online(sdev) && !scsi_noretry_cmd(scmd) &&
scsi_cmd_retry_allowed(scmd) &&
scsi_eh_should_retry_cmd(scmd)) {
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);
blk_mq_kick_requeue_list(sdev->request_queue);
} else {
/*
* If just we got sense for the device (called
* scsi_eh_get_sense), scmd->result is already
* set, do not set DID_TIME_OUT.
*/
if (!scmd->result &&
!(scmd->flags & SCMD_FORCE_EH_SUCCESS))
scmd->result |= (DID_TIME_OUT << 16);
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);
/**
* 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, val;
enum scsi_disposition rtn;
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->submitter = SUBMITTED_BY_SCSI_RESET_IOCTL;
scmd->flags |= SCMD_LAST;
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);
kfree(rq);
out_put_autopm_host:
scsi_autopm_put_host(shost);
return error;
}
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);