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kernel_optimize_test/drivers/scsi/scsi_error.c
Vladislav Bolkhovitin a9b589d90e [SCSI] scsi_error: TASK ABORTED status handling improvement 
This patch improves handling of TASK ABORTED status by Linux SCSI
mid-layer. Currently, command returned with this status considered
failed and returned to upper layers. It leads to additional error
recovery load on file systems and block layer, which sometimes can
cause undesired side effects, like I/O errors and file systems
corruptions. See http://lkml.org/lkml/2008/11/1/38, for instance.

From other side, TASK ABORTED status is returned by SCSI target if the
corresponding command was aborted by another initiator and the target
has TAS bit set in the control mode page. So, in the majority of cases
commands with TASK ABORTED status should be simply retried. In other
cases, maybe_retry path will not retry if no retries are allowed.

This patch implement suggestion by James Bottomley from
http://marc.info/?l=linux-scsi&m=121932916906009&w=2.

Signed-off-by: Vladislav Bolkhovitin <vst@vlnb.net>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-12-29 11:24:15 -06:00

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/*
* 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/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_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"
#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)
/* called with shost->host_lock held */
void scsi_eh_wakeup(struct Scsi_Host *shost)
{
if (shost->host_busy == shost->host_failed) {
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 (*eh_timed_out)(struct scsi_cmnd *);
enum blk_eh_timer_return rtn = BLK_EH_NOT_HANDLED;
scsi_log_completion(scmd, TIMEOUT_ERROR);
if (scmd->device->host->transportt->eh_timed_out)
eh_timed_out = scmd->device->host->transportt->eh_timed_out;
else if (scmd->device->host->hostt->eh_timed_out)
eh_timed_out = scmd->device->host->hostt->eh_timed_out;
else
eh_timed_out = NULL;
if (eh_timed_out) {
rtn = eh_timed_out(scmd);
switch (rtn) {
case BLK_EH_NOT_HANDLED:
break;
default:
return rtn;
}
}
if (unlikely(!scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD))) {
scmd->result |= DID_TIME_OUT << 16;
return BLK_EH_HANDLED;
}
return BLK_EH_NOT_HANDLED;
}
/**
* 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
*
* 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 (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) {
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;
return SUCCESS;
/* these three are not supported */
case COPY_ABORTED:
case VOLUME_OVERFLOW:
case MISCOMPARE:
return SUCCESS;
case MEDIUM_ERROR:
if (sshdr.asc == 0x11 || /* UNRECOVERED READ ERR */
sshdr.asc == 0x13 || /* AMNF DATA FIELD */
sshdr.asc == 0x14) { /* RECORD NOT FOUND */
return SUCCESS;
}
return NEEDS_RETRY;
case HARDWARE_ERROR:
if (scmd->device->retry_hwerror)
return ADD_TO_MLQUEUE;
else
return SUCCESS;
case ILLEGAL_REQUEST:
case BLANK_CHECK:
case DATA_PROTECT:
default:
return SUCCESS;
}
}
/**
* 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:
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 BUSY:
case QUEUE_FULL:
case RESERVATION_CONFLICT:
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;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
__func__));
if (!scmd->device->host->hostt->eh_host_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
if (rtn == SUCCESS) {
if (!scmd->device->host->hostt->skip_settle_delay)
ssleep(HOST_RESET_SETTLE_TIME);
spin_lock_irqsave(scmd->device->host->host_lock, flags);
scsi_report_bus_reset(scmd->device->host,
scmd_channel(scmd));
spin_unlock_irqrestore(scmd->device->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;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
__func__));
if (!scmd->device->host->hostt->eh_bus_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
if (rtn == SUCCESS) {
if (!scmd->device->host->hostt->skip_settle_delay)
ssleep(BUS_RESET_SETTLE_TIME);
spin_lock_irqsave(scmd->device->host->host_lock, flags);
scsi_report_bus_reset(scmd->device->host,
scmd_channel(scmd));
spin_unlock_irqrestore(scmd->device->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;
if (!scmd->device->host->hostt->eh_target_reset_handler)
return FAILED;
rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
if (rtn == SUCCESS) {
spin_lock_irqsave(scmd->device->host->host_lock, flags);
__starget_for_each_device(scsi_target(scmd->device), NULL,
__scsi_report_device_reset);
spin_unlock_irqrestore(scmd->device->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;
if (!scmd->device->host->hostt->eh_device_reset_handler)
return FAILED;
rtn = scmd->device->host->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_cmnd *scmd)
{
if (!scmd->device->host->hostt->eh_abort_handler)
return FAILED;
return scmd->device->host->hostt->eh_abort_handler(scmd);
}
/**
* scsi_try_to_abort_cmd - Ask host to abort a running command.
* @scmd: SCSI cmd to abort from Lower Level.
*
* Notes:
* This function will not return until the user's completion function
* has been called. there is no timeout on this operation. if the
* author of the low-level driver wishes this operation to be timed,
* they can provide this facility themselves. helper functions in
* scsi_error.c can be supplied to make this easier to do.
*/
static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
{
/*
* scsi_done was called just after the command timed out and before
* we had a chance to process it. (db)
*/
if (scmd->serial_number == 0)
return SUCCESS;
return __scsi_try_to_abort_cmd(scmd);
}
static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
{
if (__scsi_try_to_abort_cmd(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_prep_eh_cmnd
*
* Undo any damage done by above scsi_prep_eh_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_Host *shost = sdev->host;
DECLARE_COMPLETION_ONSTACK(done);
unsigned long timeleft;
unsigned long flags;
struct scsi_eh_save ses;
int rtn;
scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
shost->eh_action = &done;
spin_lock_irqsave(shost->host_lock, flags);
scsi_log_send(scmd);
shost->hostt->queuecommand(scmd, scsi_eh_done);
spin_unlock_irqrestore(shost->host_lock, flags);
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:
break;
default:
rtn = FAILED;
break;
}
} else {
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, 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_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;
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);
if (rtn == SUCCESS) {
scmd->eh_eflags &= ~SCSI_EH_CANCEL_CMD;
if (!scsi_device_online(scmd->device) ||
!scsi_eh_tur(scmd)) {
scsi_eh_finish_cmd(scmd, done_q);
}
} else
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: aborting"
" cmd failed:"
"0x%p\n",
current->comm,
scmd));
}
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) {
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) {
if (!scsi_device_online(sdev) ||
!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)
{
struct scsi_cmnd *scmd, *tgtr_scmd, *next;
unsigned int id = 0;
int rtn;
do {
tgtr_scmd = NULL;
list_for_each_entry(scmd, work_q, eh_entry) {
if (id == scmd_id(scmd)) {
tgtr_scmd = scmd;
break;
}
}
if (!tgtr_scmd) {
/* not one exactly equal; find the next highest */
list_for_each_entry(scmd, work_q, eh_entry) {
if (scmd_id(scmd) > id &&
(!tgtr_scmd ||
scmd_id(tgtr_scmd) > scmd_id(scmd)))
tgtr_scmd = scmd;
}
}
if (!tgtr_scmd)
/* no more commands, that's it */
break;
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
"to target %d\n",
current->comm, id));
rtn = scsi_try_target_reset(tgtr_scmd);
if (rtn == SUCCESS) {
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if (id == scmd_id(scmd))
if (!scsi_device_online(scmd->device) ||
!scsi_eh_tur(tgtr_scmd))
scsi_eh_finish_cmd(scmd,
done_q);
}
} else
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
" failed target: "
"%d\n",
current->comm, id));
id++;
} while(id != 0);
return list_empty(work_q);
}
/**
* 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;
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) {
list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if (channel == scmd_channel(scmd))
if (!scsi_device_online(scmd->device) ||
!scsi_eh_tur(scmd))
scsi_eh_finish_cmd(scmd,
done_q);
}
} else {
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: BRST"
" failed chan: %d\n",
current->comm,
channel));
}
}
return list_empty(work_q);
}
/**
* 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;
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_for_each_entry_safe(scmd, next, work_q, eh_entry) {
if (!scsi_device_online(scmd->device) ||
(!scsi_eh_try_stu(scmd) && !scsi_eh_tur(scmd)) ||
!scsi_eh_tur(scmd))
scsi_eh_finish_cmd(scmd, done_q);
}
} else {
SCSI_LOG_ERROR_RECOVERY(3, printk("%s: HRST"
" failed\n",
current->comm));
}
}
return list_empty(work_q);
}
/**
* 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 blk_failfast_transport(scmd->request);
case DID_PARITY:
return blk_failfast_dev(scmd->request);
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 blk_failfast_driver(scmd->request);
}
switch (status_byte(scmd->result)) {
case CHECK_CONDITION:
/*
* assume caller has checked sense and determinted
* the check condition was retryable.
*/
return blk_failfast_dev(scmd->request);
}
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:
/*
* 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:
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");
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;
}
}
/**
* 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; scsi_allocate_request()
* may sleep.
*
* Notes:
* We queue up an asynchronous "ALLOW MEDIUM REMOVAL" request on the
* head of the devices request queue, and continue.
*
* Bugs:
* scsi_allocate_request() may sleep waiting for existing requests to
* be processed. However, since we haven't kicked off any request
* processing for this host, this may deadlock.
*
* If scsi_allocate_request() fails for what ever reason, we
* completely forget to lock the door.
*/
static void scsi_eh_lock_door(struct scsi_device *sdev)
{
unsigned char cmnd[MAX_COMMAND_SIZE];
cmnd[0] = ALLOW_MEDIUM_REMOVAL;
cmnd[1] = 0;
cmnd[2] = 0;
cmnd[3] = 0;
cmnd[4] = SCSI_REMOVAL_PREVENT;
cmnd[5] = 0;
scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
5, NULL, NULL, GFP_KERNEL);
}
/**
* 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);
}
/**
* 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 singal 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->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);
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 = scsi_get_command(dev, GFP_KERNEL);
struct Scsi_Host *shost = dev->host;
struct request req;
unsigned long flags;
int rtn;
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);
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);
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