/*
* 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 <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_transport.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>
#include "scsi_priv.h"
#include "scsi_logging.h"
#include "scsi_transport_api.h"
#include <trace/events/scsi.h>
static void scsi_eh_done(struct scsi_cmnd *scmd);
#define SENSE_TIMEOUT (10*HZ)
/*
* 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);
/* called with shost->host_lock held */
void scsi_eh_wakeup(struct Scsi_Host *shost)
{
if (shost->host_busy == shost->host_failed) {
trace_scsi_eh_wakeup(shost);
wake_up_process(shost->ehandler);
SCSI_LOG_ERROR_RECOVERY(5,
printk("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);
/**
* scsi_eh_scmd_add - add scsi cmd to error handling.
* @scmd: scmd to run eh on.
* @eh_flag: optional SCSI_EH flag.
*
* Return value:
* 0 on failure.
*/
int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
{
struct Scsi_Host *shost = scmd->device->host;
unsigned long flags;
int ret = 0;
if (!shost->ehandler)
return 0;
spin_lock_irqsave(shost->host_lock, flags);
if (scsi_host_set_state(shost, SHOST_RECOVERY))
if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY))
goto out_unlock;
ret = 1;
scmd->eh_eflags |= eh_flag;
list_add_tail(&scmd->eh_entry, &shost->eh_cmd_q);
shost->host_failed++;
scsi_eh_wakeup(shost);
out_unlock:
spin_unlock_irqrestore(shost->host_lock, flags);
return ret;
}
/**
* 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 = req->special;
enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
struct Scsi_Host *host = scmd->device->host;
trace_scsi_dispatch_cmd_timeout(scmd);
scsi_log_completion(scmd, TIMEOUT_ERROR);
if (host->transportt->eh_timed_out)
rtn = host->transportt->eh_timed_out(scmd);
else if (host->hostt->eh_timed_out)
rtn = host->hostt->eh_timed_out(scmd);
scmd->result |= DID_TIME_OUT << 16;
if (unlikely(rtn == BLK_EH_NOT_HANDLED &&
!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD)))
rtn = BLK_EH_HANDLED;
return rtn;
}
/**
* scsi_block_when_processing_errors - Prevent cmds from being queued.
* @sdev: Device on which we are performing recovery.
*
* Description:
* We block until the host is out of error recovery, and then check to
* see whether the host or the device is offline.
*
* Return value:
* 0 when dev was taken offline by error recovery. 1 OK to proceed.
*/
int scsi_block_when_processing_errors(struct scsi_device *sdev)
{
int online;
wait_event(sdev->host->host_wait, !scsi_host_in_recovery(sdev->host));
online = scsi_device_online(sdev);
SCSI_LOG_ERROR_RECOVERY(5, printk("%s: rtn: %d\n", __func__,
online));
return online;
}
EXPORT_SYMBOL(scsi_block_when_processing_errors);
#ifdef CONFIG_SCSI_LOGGING
/**
* scsi_eh_prt_fail_stats - Log info on failures.
* @shost: scsi host being recovered.
* @work_q: Queue of scsi cmds to process.
*/
static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
struct list_head *work_q)
{
struct scsi_cmnd *scmd;
struct scsi_device *sdev;
int total_failures = 0;
int cmd_failed = 0;
int cmd_cancel = 0;
int devices_failed = 0;
shost_for_each_device(sdev, shost) {
list_for_each_entry(scmd, work_q, eh_entry) {
if (scmd->device == sdev) {
++total_failures;
if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD)
++cmd_cancel;
else
++cmd_failed;
}
}
if (cmd_cancel || cmd_failed) {
SCSI_LOG_ERROR_RECOVERY(3,
sdev_printk(KERN_INFO, sdev,
"%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, printk("Total of %d commands on %d"
" devices require eh work\n",
total_failures, devices_failed));
}
#endif
/**
* scsi_check_sense - Examine scsi cmd sense
* @scmd: Cmd to have sense checked.
*
* Return value:
* SUCCESS or FAILED or NEEDS_RETRY or TARGET_ERROR
*
* Notes:
* When a deferred error is detected the current command has
* not been executed and needs retrying.
*/
static 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 */
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;
if (scsi_sense_is_deferred(&sshdr))
return NEEDS_RETRY;
if (sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh &&
sdev->scsi_dh_data->scsi_dh->check_sense) {
int rc;
rc = sdev->scsi_dh_data->scsi_dh->check_sense(sdev, &sshdr);
if (rc != SCSI_RETURN_NOT_HANDLED)
return rc;
/* handler does not care. Drop down to default handling */
}
/*
* 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;
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;
}
}
/*
* 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;
if (sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
scmd_printk(KERN_WARNING, scmd,
"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)
scmd_printk(KERN_WARNING, scmd,
"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)
scmd_printk(KERN_WARNING, scmd,
"Warning! Received an indication that the "
"LUN reached a thin provisioning soft "
"threshold.\n");
/*
* Pass the UA upwards for a determination in the completion
* functions.
*/
return SUCCESS;
/* these are not supported */
case COPY_ABORTED:
case VOLUME_OVERFLOW:
case MISCOMPARE:
case BLANK_CHECK:
case DATA_PROTECT:
return TARGET_ERROR;
case MEDIUM_ERROR:
if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
sshdr.asc == 0x13 || /* AMNF DATA FIELD */
sshdr.asc == 0x14) { /* RECORD NOT FOUND */
return TARGET_ERROR;
}
return NEEDS_RETRY;
case HARDWARE_ERROR:
if (scmd->device->retry_hwerror)
return ADD_TO_MLQUEUE;
else
return TARGET_ERROR;
case ILLEGAL_REQUEST:
if (sshdr.asc == 0x20 || /* Invalid command operation code */
sshdr.asc == 0x21 || /* Logical block address out of range */
sshdr.asc == 0x24 || /* Invalid field in cdb */
sshdr.asc == 0x26) { /* Parameter value invalid */
return TARGET_ERROR;
}
return SUCCESS;
default:
return SUCCESS;
}
}
static void scsi_handle_queue_ramp_up(struct scsi_device *sdev)
{
struct scsi_host_template *sht = sdev->host->hostt;
struct scsi_device *tmp_sdev;
if (!sht->change_queue_depth ||
sdev->queue_depth >= sdev->max_queue_depth)
return;
if (time_before(jiffies,
sdev->last_queue_ramp_up + sdev->queue_ramp_up_period))
return;
if (time_before(jiffies,
sdev->last_queue_full_time + sdev->queue_ramp_up_period))
return;
/*
* Walk all devices of a target and do
* ramp up on them.
*/
shost_for_each_device(tmp_sdev, sdev->host) {
if (tmp_sdev->channel != sdev->channel ||
tmp_sdev->id != sdev->id ||
tmp_sdev->queue_depth == sdev->max_queue_depth)
continue;
/*
* call back into LLD to increase queue_depth by one
* with ramp up reason code.
*/
sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth + 1,
SCSI_QDEPTH_RAMP_UP);
sdev->last_queue_ramp_up = jiffies;
}
}
static void scsi_handle_queue_full(struct scsi_device *sdev)
{
struct scsi_host_template *sht = sdev->host->hostt;
struct scsi_device *tmp_sdev;
if (!sht->change_queue_depth)
return;
shost_for_each_device(tmp_sdev, sdev->host) {
if (tmp_sdev->channel != sdev->channel ||
tmp_sdev->id != sdev->id)
continue;
/*
* We do not know the number of commands that were at
* the device when we got the queue full so we start
* from the highest possible value and work our way down.
*/
sht->change_queue_depth(tmp_sdev, tmp_sdev->queue_depth - 1,
SCSI_QDEPTH_QFULL);
}
}
/**
* 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);
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,
printk("%s scmd: %p result: %x\n",
__func__, scmd, 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 hsot 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, printk("%s: Snd Host RST\n",
__func__));
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, printk("%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;
}
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 recory
* @scmd: SCSI command structure to hijack
* @ses: structure to save restore information
* @cmnd: CDB to send. Can be NULL if no new cmnd is needed
* @cmnd_size: size in bytes of @cmnd (must be <= BLK_MAX_CDB)
* @sense_bytes: size of sense data to copy. or 0 (if != 0 @cmnd is ignored)
*
* This function is used to save a scsi command information before re-execution
* as part of the error recovery process. If @sense_bytes is 0 the command
* sent must be one that does not transfer any data. If @sense_bytes != 0
* @cmnd is ignored and this functions sets up a REQUEST_SENSE command
* and cmnd buffers to read @sense_bytes into @scmd->sense_buffer.
*/
void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
unsigned char *cmnd, int cmnd_size, unsigned sense_bytes)
{
struct scsi_device *sdev = scmd->device;
/*
* We need saved copies of a number of fields - this is because
* error handling may need to overwrite these with different values
* to run different commands, and once error handling is complete,
* we will need to restore these values prior to running the actual
* command.
*/
ses->cmd_len = scmd->cmd_len;
ses->cmnd = scmd->cmnd;
ses->data_direction = scmd->sc_data_direction;
ses->sdb = scmd->sdb;
ses->next_rq = scmd->request->next_rq;
ses->result = scmd->result;
ses->underflow = scmd->underflow;
ses->prot_op = scmd->prot_op;
scmd->prot_op = SCSI_PROT_NORMAL;
scmd->cmnd = ses->eh_cmnd;
memset(scmd->cmnd, 0, BLK_MAX_CDB);
memset(&scmd->sdb, 0, sizeof(scmd->sdb));
scmd->request->next_rq = NULL;
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 = 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 recory
* @scmd: SCSI command structure to restore
* @ses: saved information from a coresponding call to scsi_eh_prep_cmnd
*
* Undo any damage done by above scsi_eh_prep_cmnd().
*/
void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
{
/*
* Restore original data
*/
scmd->cmd_len = ses->cmd_len;
scmd->cmnd = ses->cmnd;
scmd->sc_data_direction = ses->data_direction;
scmd->sdb = ses->sdb;
scmd->request->next_rq = ses->next_rq;
scmd->result = ses->result;
scmd->underflow = ses->underflow;
scmd->prot_op = ses->prot_op;
}
EXPORT_SYMBOL(scsi_eh_restore_cmnd);
/**
* scsi_send_eh_cmnd - submit a scsi command as part of error recory
* @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_driver *sdrv = scsi_cmd_to_driver(scmd);
struct Scsi_Host *shost = sdev->host;
DECLARE_COMPLETION_ONSTACK(done);
unsigned long timeleft;
struct scsi_eh_save ses;
int rtn;
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;
shost->hostt->queuecommand(shost, scmd);
timeleft = wait_for_completion_timeout(&done, timeout);
shost->eh_action = NULL;
scsi_log_completion(scmd, SUCCESS);
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: scmd: %p, timeleft: %ld\n",
__func__, scmd, 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 tell the host to forget
* about this command.
*/
if (timeleft) {
rtn = scsi_eh_completed_normally(scmd);
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: scsi_eh_completed_normally %x\n",
__func__, rtn));
switch (rtn) {
case SUCCESS:
case NEEDS_RETRY:
case FAILED:
case TARGET_ERROR:
break;
case ADD_TO_MLQUEUE:
rtn = NEEDS_RETRY;
break;
default:
rtn = FAILED;
break;
}
} else {
scsi_abort_eh_cmnd(scmd);
rtn = FAILED;
}
scsi_eh_restore_cmnd(scmd, &ses);
if (sdrv && sdrv->eh_action)
rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn);
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, SENSE_TIMEOUT, ~0);
}
/**
* 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)
{
scmd->device->host->host_failed--;
scmd->eh_eflags = 0;
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;
int rtn;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if ((scmd->eh_eflags & SCSI_EH_CANCEL_CMD) ||
SCSI_SENSE_VALID(scmd))
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, printk("sense requested for %p"
" result %x\n", scmd,
scmd->result));
SCSI_LOG_ERROR_RECOVERY(3, scsi_print_sense("bh", scmd));
rtn = scsi_decide_disposition(scmd);
/*
* if the result was normal, then just pass it along to the
* upper level.
*/
if (rtn == SUCCESS)
/* we don't want this command reissued, just
* finished with the sense data, so set
* retries to the max allowed to ensure it
* won't get reissued */
scmd->retries = scmd->allowed;
else if (rtn != NEEDS_RETRY)
continue;
scsi_eh_finish_cmd(scmd, done_q);
}
return list_empty(work_q);
}
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, SENSE_TIMEOUT, 0);
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
__func__, scmd, 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;
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)
scsi_eh_finish_cmd(scmd, done_q);
else
list_move_tail(&scmd->eh_entry, work_q);
}
}
return list_empty(work_q);
}
/**
* scsi_eh_abort_cmds - abort pending commands.
* @work_q: &list_head for pending commands.
* @done_q: &list_head for processed commands.
*
* Decription:
* Try and see whether or not it makes sense to try and abort the
* running command. This only works out to be the case if we have one
* command that has timed out. If the command simply failed, it makes
* no sense to try and abort the command, since as far as the shost
* adapter is concerned, it isn't running.
*/
static int scsi_eh_abort_cmds(struct list_head *work_q,
struct list_head *done_q)
{
struct scsi_cmnd *scmd, *next;
LIST_HEAD(check_list);
int rtn;
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if (!(scmd->eh_eflags & SCSI_EH_CANCEL_CMD))
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting cmd:"
"0x%p\n", current->comm,
scmd));
rtn = scsi_try_to_abort_cmd(scmd->device->host->hostt, scmd);
if (rtn == SUCCESS || rtn == FAST_IO_FAIL) {
scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
if (rtn == FAST_IO_FAIL)
scsi_eh_finish_cmd(scmd, done_q);
else
list_move_tail(&scmd->eh_entry, &check_list);
} else
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
" cmd failed:"
"0x%p\n",
current->comm,
scmd));
}
return scsi_eh_test_devices(&check_list, work_q, done_q, 0);
}
/**
* 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) {
stu_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev && SCSI_SENSE_VALID(scmd) &&
scsi_check_sense(scmd) == FAILED ) {
stu_scmd = scmd;
break;
}
if (!stu_scmd)
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending START_UNIT to sdev:"
" 0x%p\n", current->comm, sdev));
if (!scsi_eh_try_stu(stu_scmd)) {
if (!scsi_device_online(sdev) ||
!scsi_eh_tur(stu_scmd)) {
list_for_each_entry_safe(scmd, next,
work_q, eh_entry) {
if (scmd->device == sdev)
scsi_eh_finish_cmd(scmd, done_q);
}
}
} else {
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: START_UNIT failed to sdev:"
" 0x%p\n", current->comm, sdev));
}
}
return list_empty(work_q);
}
/**
* scsi_eh_bus_device_reset - send bdr if needed
* @shost: scsi host being recovered.
* @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) {
bdr_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry)
if (scmd->device == sdev) {
bdr_scmd = scmd;
break;
}
if (!bdr_scmd)
continue;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending BDR sdev:"
" 0x%p\n", current->comm,
sdev));
rtn = scsi_try_bus_device_reset(bdr_scmd);
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_finish_cmd(scmd,
done_q);
}
}
} else {
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BDR"
" failed sdev:"
"0x%p\n",
current->comm,
sdev));
}
}
return list_empty(work_q);
}
/**
* 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;
scmd = list_entry(tmp_list.next, struct scsi_cmnd, eh_entry);
id = scmd_id(scmd);
SCSI_LOG_ERROR_RECOVERY(3, printk("%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, printk("%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++) {
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, printk("%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, printk("%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
* @work_q: list_head for processed commands.
* @done_q: list_head for processed commands.
*/
static int scsi_eh_host_reset(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, printk("%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, printk("%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 processed 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;
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");
scsi_device_set_state(scmd->device, SDEV_OFFLINE);
if (scmd->eh_eflags & SCSI_EH_CANCEL_CMD) {
/*
* FIXME: Handle lost cmds.
*/
}
scsi_eh_finish_cmd(scmd, done_q);
}
return;
}
/**
* scsi_noretry_cmd - determinte if command should be failed fast
* @scmd: SCSI cmd to examine.
*/
int scsi_noretry_cmd(struct scsi_cmnd *scmd)
{
switch (host_byte(scmd->result)) {
case DID_OK:
break;
case DID_BUS_BUSY:
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);
}
switch (status_byte(scmd->result)) {
case CHECK_CONDITION:
/*
* assume caller has checked sense and determinted
* the check condition was retryable.
*/
if (scmd->request->cmd_flags & REQ_FAILFAST_DEV ||
scmd->request->cmd_type == REQ_TYPE_BLOCK_PC)
return 1;
}
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, printk("%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_NO_CONNECT:
case DID_BAD_TARGET:
case DID_ABORT:
/*
* note - this means that we just report the status back
* to the top level driver, not that we actually think
* that it indicates SUCCESS.
*/
return SUCCESS;
/*
* when the low level driver returns did_soft_error,
* it is responsible for keeping an internal retry counter
* in order to avoid endless loops (db)
*
* actually this is a bug in this function here. we should
* be mindful of the maximum number of retries specified
* and not get stuck in a loop.
*/
case DID_SOFT_ERROR:
goto maybe_retry;
case DID_IMM_RETRY:
return NEEDS_RETRY;
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.
*/
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:
scsi_handle_queue_ramp_up(scmd->device);
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;
else if (rtn == TARGET_ERROR) {
/*
* Need to modify host byte to signal a
* permanent target failure
*/
set_host_byte(scmd, DID_TARGET_FAILURE);
rtn = SUCCESS;
}
/* 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, int uptodate)
{
__blk_put_request(req->q, req);
}
/**
* scsi_eh_lock_door - Prevent medium removal for the specified device
* @sdev: SCSI device to prevent medium removal
*
* Locking:
* We must be called from process context.
*
* Notes:
* We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
* head of the devices request queue, and continue.
*/
static void scsi_eh_lock_door(struct scsi_device *sdev)
{
struct request *req;
/*
* blk_get_request with GFP_KERNEL (__GFP_WAIT) sleeps until a
* request becomes available
*/
req = blk_get_request(sdev->request_queue, READ, GFP_KERNEL);
req->cmd[0] = ALLOW_MEDIUM_REMOVAL;
req->cmd[1] = 0;
req->cmd[2] = 0;
req->cmd[3] = 0;
req->cmd[4] = SCSI_REMOVAL_PREVENT;
req->cmd[5] = 0;
req->cmd_len = COMMAND_SIZE(req->cmd[0]);
req->cmd_type = REQ_TYPE_BLOCK_PC;
req->cmd_flags |= REQ_QUIET;
req->timeout = 10 * HZ;
req->retries = 5;
blk_execute_rq_nowait(req->q, NULL, req, 1, eh_lock_door_done);
}
/**
* 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->locked)
scsi_eh_lock_door(sdev);
}
/*
* next free up anything directly waiting upon the host. this
* will be requests for character device operations, and also for
* ioctls to queued block devices.
*/
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: waking up host to restart\n",
__func__));
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(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, printk("%s: flush"
" retry cmd: %p\n",
current->comm,
scmd));
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, printk("%s: flush finish"
" cmd: %p\n",
current->comm, scmd));
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))
if (!scsi_eh_abort_cmds(&eh_work_q, &eh_done_q))
scsi_eh_ready_devs(shost, &eh_work_q, &eh_done_q);
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.
*/
set_current_state(TASK_INTERRUPTIBLE);
while (!kthread_should_stop()) {
if ((shost->host_failed == 0 && shost->host_eh_scheduled == 0) ||
shost->host_failed != shost->host_busy) {
SCSI_LOG_ERROR_RECOVERY(1,
printk("Error handler scsi_eh_%d sleeping\n",
shost->host_no));
schedule();
set_current_state(TASK_INTERRUPTIBLE);
continue;
}
__set_current_state(TASK_RUNNING);
SCSI_LOG_ERROR_RECOVERY(1,
printk("Error handler scsi_eh_%d waking up\n",
shost->host_no));
/*
* 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,
printk(KERN_ERR "Error handler 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);
/*
* 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_INTERRUPTIBLE);
}
__set_current_state(TASK_RUNNING);
SCSI_LOG_ERROR_RECOVERY(1,
printk("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)
{
}
/*
* Function: scsi_reset_provider
*
* Purpose: Send requested reset to a bus or device at any phase.
*
* Arguments: device - device to send reset to
* flag - reset type (see scsi.h)
*
* Returns: SUCCESS/FAILURE.
*
* Notes: This is used by the SCSI Generic driver to provide
* Bus/Device reset capability.
*/
int
scsi_reset_provider(struct scsi_device *dev, int flag)
{
struct scsi_cmnd *scmd;
struct Scsi_Host *shost = dev->host;
struct request req;
unsigned long flags;
int rtn;
if (scsi_autopm_get_host(shost) < 0)
return FAILED;
scmd = scsi_get_command(dev, GFP_KERNEL);
blk_rq_init(NULL, &req);
scmd->request = &req;
scmd->cmnd = req.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 (flag) {
case SCSI_TRY_RESET_DEVICE:
rtn = scsi_try_bus_device_reset(scmd);
if (rtn == SUCCESS)
break;
/* FALLTHROUGH */
case SCSI_TRY_RESET_TARGET:
rtn = scsi_try_target_reset(scmd);
if (rtn == SUCCESS)
break;
/* FALLTHROUGH */
case SCSI_TRY_RESET_BUS:
rtn = scsi_try_bus_reset(scmd);
if (rtn == SUCCESS)
break;
/* FALLTHROUGH */
case SCSI_TRY_RESET_HOST:
rtn = scsi_try_host_reset(scmd);
break;
default:
rtn = FAILED;
}
spin_lock_irqsave(shost->host_lock, flags);
shost->tmf_in_progress = 0;
spin_unlock_irqrestore(shost->host_lock, flags);
/*
* be sure to wake up anyone who was sleeping or had their queue
* suspended while we performed the TMF.
*/
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: waking up host to restart after TMF\n",
__func__));
wake_up(&shost->host_wait);
scsi_run_host_queues(shost);
scsi_next_command(scmd);
scsi_autopm_put_host(shost);
return rtn;
}
EXPORT_SYMBOL(scsi_reset_provider);
/**
* scsi_normalize_sense - normalize main elements from either fixed or
* descriptor sense data format into a common format.
*
* @sense_buffer: byte array containing sense data returned by device
* @sb_len: number of valid bytes in sense_buffer
* @sshdr: pointer to instance of structure that common
* elements are written to.
*
* Notes:
* The "main elements" from sense data are: response_code, sense_key,
* asc, ascq and additional_length (only for descriptor format).
*
* Typically this function can be called after a device has
* responded to a SCSI command with the CHECK_CONDITION status.
*
* Return value:
* 1 if valid sense data information found, else 0;
*/
int scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
struct scsi_sense_hdr *sshdr)
{
if (!sense_buffer || !sb_len)
return 0;
memset(sshdr, 0, sizeof(struct scsi_sense_hdr));
sshdr->response_code = (sense_buffer[0] & 0x7f);
if (!scsi_sense_valid(sshdr))
return 0;
if (sshdr->response_code >= 0x72) {
/*
* descriptor format
*/
if (sb_len > 1)
sshdr->sense_key = (sense_buffer[1] & 0xf);
if (sb_len > 2)
sshdr->asc = sense_buffer[2];
if (sb_len > 3)
sshdr->ascq = sense_buffer[3];
if (sb_len > 7)
sshdr->additional_length = sense_buffer[7];
} else {
/*
* fixed format
*/
if (sb_len > 2)
sshdr->sense_key = (sense_buffer[2] & 0xf);
if (sb_len > 7) {
sb_len = (sb_len < (sense_buffer[7] + 8)) ?
sb_len : (sense_buffer[7] + 8);
if (sb_len > 12)
sshdr->asc = sense_buffer[12];
if (sb_len > 13)
sshdr->ascq = sense_buffer[13];
}
}
return 1;
}
EXPORT_SYMBOL(scsi_normalize_sense);
int scsi_command_normalize_sense(struct scsi_cmnd *cmd,
struct scsi_sense_hdr *sshdr)
{
return scsi_normalize_sense(cmd->sense_buffer,
SCSI_SENSE_BUFFERSIZE, sshdr);
}
EXPORT_SYMBOL(scsi_command_normalize_sense);
/**
* scsi_sense_desc_find - search for a given descriptor type in descriptor sense data format.
* @sense_buffer: byte array of descriptor format sense data
* @sb_len: number of valid bytes in sense_buffer
* @desc_type: value of descriptor type to find
* (e.g. 0 -> information)
*
* Notes:
* only valid when sense data is in descriptor format
*
* Return value:
* pointer to start of (first) descriptor if found else NULL
*/
const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
int desc_type)
{
int add_sen_len, add_len, desc_len, k;
const u8 * descp;
if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
return NULL;
if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
return NULL;
add_sen_len = (add_sen_len < (sb_len - 8)) ?
add_sen_len : (sb_len - 8);
descp = &sense_buffer[8];
for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
descp += desc_len;
add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
desc_len = add_len + 2;
if (descp[0] == desc_type)
return descp;
if (add_len < 0) // short descriptor ??
break;
}
return NULL;
}
EXPORT_SYMBOL(scsi_sense_desc_find);
/**
* 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:
* 1 if information field found, 0 if not found.
*/
int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
u64 * info_out)
{
int j;
const u8 * ucp;
u64 ull;
if (sb_len < 7)
return 0;
switch (sense_buffer[0] & 0x7f) {
case 0x70:
case 0x71:
if (sense_buffer[0] & 0x80) {
*info_out = (sense_buffer[3] << 24) +
(sense_buffer[4] << 16) +
(sense_buffer[5] << 8) + sense_buffer[6];
return 1;
} else
return 0;
case 0x72:
case 0x73:
ucp = scsi_sense_desc_find(sense_buffer, sb_len,
0 /* info desc */);
if (ucp && (0xa == ucp[1])) {
ull = 0;
for (j = 0; j < 8; ++j) {
if (j > 0)
ull <<= 8;
ull |= ucp[4 + j];
}
*info_out = ull;
return 1;
} else
return 0;
default:
return 0;
}
}
EXPORT_SYMBOL(scsi_get_sense_info_fld);
/**
* scsi_build_sense_buffer - build sense data in a buffer
* @desc: Sense format (non zero == descriptor format,
* 0 == fixed format)
* @buf: Where to build sense data
* @key: Sense key
* @asc: Additional sense code
* @ascq: Additional sense code qualifier
*
**/
void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
{
if (desc) {
buf[0] = 0x72; /* descriptor, current */
buf[1] = key;
buf[2] = asc;
buf[3] = ascq;
buf[7] = 0;
} else {
buf[0] = 0x70; /* fixed, current */
buf[2] = key;
buf[7] = 0xa;
buf[12] = asc;
buf[13] = ascq;
}
}
EXPORT_SYMBOL(scsi_build_sense_buffer);