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linux/drivers/scsi/scsi_error.c
Damien Le Moal 8f8fed0cdb scsi: core: save/restore command resid for error handling 
When a non-passthrough command is terminated with CHECK CONDITION, request
sense is executed by hijacking the command descriptor. Since
scsi_eh_prep_cmnd() and scsi_eh_restore_cmnd() do not save/restore the
original command resid, the value returned on failure of the original
command is lost and replaced with the value set by the execution of the
request sense command. This value may in many instances be unaligned to the
device sector size, causing sd_done() to print a warning message about the
incorrect unaligned resid before the command is retried.

Fix this problem by saving the original command residual in struct
scsi_eh_save using scsi_eh_prep_cmnd() and restoring it in
scsi_eh_restore_cmnd(). In addition, to make sure that the request sense
command is executed with a correctly initialized command structure, also
reset the residual to 0 in scsi_eh_prep_cmnd() after saving the original
command value in struct scsi_eh_save.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191001074839.1994-1-damien.lemoal@wdc.com
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2019-10-03 21:43:04 -04:00

2470 lines
68 KiB
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// 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>
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) {
/*
* Set the command to complete first in order to prevent a real
* completion from releasing the command while error handling
* is using it. If the command was already completed, then the
* lower level driver beat the timeout handler, and it is safe
* to return without escalating error recovery.
*
* If timeout handling lost the race to a real completion, the
* block layer may ignore that due to a fake timeout injection,
* so return RESET_TIMER to allow error handling another shot
* at this command.
*/
if (test_and_set_bit(SCMD_STATE_COMPLETE, &scmd->state))
return BLK_EH_RESET_TIMER;
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);
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->result = scmd->result;
ses->resid_len = scmd->req.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;
scmd->cmnd = ses->eh_cmnd;
memset(scmd->cmnd, 0, BLK_MAX_CDB);
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
scmd->result = 0;
scmd->req.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 > 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->result = ses->result;
scmd->req.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 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, 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->scsi_done = scsi_eh_done;
/*
* 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 = SCSI_MLQUEUE_DEVICE_BUSY;
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 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);
}
/**
* 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;
}
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);
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