scsi_error.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,846 行 · 第 1/4 页

	scmd->owner = SCSI_OWNER_LOWLEVEL;

	if (scmd->device->scsi_level <= SCSI_2)
		scmd->cmnd[1] = (scmd->cmnd[1] & 0x1f) |
			(scmd->device->lun << 5 & 0xe0);

	scsi_add_timer(scmd, timeout, scsi_eh_times_out);

	/*
	 * set up the semaphore so we wait for the command to complete.
	 */
	scmd->device->host->eh_action = &sem;
	scmd->request->rq_status = RQ_SCSI_BUSY;

	spin_lock_irqsave(scmd->device->host->host_lock, flags);
	scsi_log_send(scmd);
	host->hostt->queuecommand(scmd, scsi_eh_done);
	spin_unlock_irqrestore(scmd->device->host->host_lock, flags);

	down(&sem);
	scsi_log_completion(scmd, SUCCESS);

	scmd->device->host->eh_action = NULL;

	/*
	 * see if timeout.  if so, tell the host to forget about it.
	 * in other words, we don't want a callback any more.
	 */
	if (scsi_eh_eflags_chk(scmd, SCSI_EH_REC_TIMEOUT)) {
		scsi_eh_eflags_clr(scmd,  SCSI_EH_REC_TIMEOUT);
		scmd->owner = SCSI_OWNER_LOWLEVEL;

		/*
		 * as far as the low level driver is
		 * concerned, this command is still active, so
		 * we must give the low level driver a chance
		 * to abort it. (db) 
		 *
		 * FIXME(eric) - we are not tracking whether we could
		 * abort a timed out command or not.  not sure how
		 * we should treat them differently anyways.
		 */
		spin_lock_irqsave(scmd->device->host->host_lock, flags);
		if (scmd->device->host->hostt->eh_abort_handler)
			scmd->device->host->hostt->eh_abort_handler(scmd);
		spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
			
		scmd->request->rq_status = RQ_SCSI_DONE;
		scmd->owner = SCSI_OWNER_ERROR_HANDLER;
			
		rtn = FAILED;
	}

	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd: %p, rtn:%x\n",
					  __FUNCTION__, scmd, rtn));

	/*
	 * now examine the actual status codes to see whether the command
	 * actually did complete normally.
	 */
	if (rtn == SUCCESS) {
		rtn = scsi_eh_completed_normally(scmd);
		SCSI_LOG_ERROR_RECOVERY(3,
			printk("%s: scsi_eh_completed_normally %x\n",
			       __FUNCTION__, rtn));
		switch (rtn) {
		case SUCCESS:
		case NEEDS_RETRY:
		case FAILED:
			break;
		default:
			rtn = FAILED;
			break;
		}
	}

	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)
{
	static unsigned char generic_sense[6] =
	{REQUEST_SENSE, 0, 0, 0, 252, 0};
	unsigned char *scsi_result;
	int saved_result;
	int rtn;

	memcpy(scmd->cmnd, generic_sense, sizeof(generic_sense));

	scsi_result = kmalloc(252, GFP_ATOMIC | (scmd->device->host->hostt->unchecked_isa_dma) ? __GFP_DMA : 0);


	if (unlikely(!scsi_result)) {
		printk(KERN_ERR "%s: cannot allocate scsi_result.\n",
		       __FUNCTION__);
		return FAILED;
	}

	/*
	 * zero the sense buffer.  some host adapters automatically always
	 * request sense, so it is not a good idea that
	 * scmd->request_buffer and scmd->sense_buffer point to the same
	 * address (db).  0 is not a valid sense code. 
	 */
	memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));
	memset(scsi_result, 0, 252);

	saved_result = scmd->result;
	scmd->request_buffer = scsi_result;
	scmd->request_bufflen = 252;
	scmd->use_sg = 0;
	scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
	scmd->sc_data_direction = DMA_FROM_DEVICE;
	scmd->underflow = 0;

	rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);

	/* last chance to have valid sense data */
	if(!SCSI_SENSE_VALID(scmd)) {
		memcpy(scmd->sense_buffer, scmd->request_buffer,
		       sizeof(scmd->sense_buffer));
	}

	kfree(scsi_result);

	/*
	 * when we eventually call scsi_finish, we really wish to complete
	 * the original request, so let's restore the original data. (db)
	 */
	scsi_setup_cmd_retry(scmd);
	scmd->result = saved_result;
	return rtn;
}

/**
 * scsi_eh_finish_cmd - Handle a cmd that eh is finished with.
 * @scmd:	Original SCSI cmd that eh has finished.
 * @done_q:	Queue for processed commands.
 *
 * Notes:
 *    We don't want to use the normal command completion while we are are
 *    still handling errors - it may cause other commands to be queued,
 *    and that would disturb what we are doing.  thus we really want to
 *    keep a list of pending commands for final completion, and once we
 *    are ready to leave error handling we handle completion for real.
 **/
static void scsi_eh_finish_cmd(struct scsi_cmnd *scmd,
			       struct list_head *done_q)
{
	scmd->device->host->host_failed--;
	scmd->state = SCSI_STATE_BHQUEUE;

	scsi_eh_eflags_clr_all(scmd);

	/*
	 * set this back so that the upper level can correctly free up
	 * things.
	 */
	scsi_setup_cmd_retry(scmd);
	list_move_tail(&scmd->eh_entry, done_q);
}

/**
 * scsi_eh_get_sense - Get device sense data.
 * @work_q:	Queue of commands to process.
 * @done_q:	Queue of proccessed 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, that 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.
 **/
static int scsi_eh_get_sense(struct list_head *work_q,
			     struct list_head *done_q)
{
	struct list_head *lh, *lh_sf;
	struct scsi_cmnd *scmd;
	int rtn;

	list_for_each_safe(lh, lh_sf, work_q) {
		scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
		if (scsi_eh_eflags_chk(scmd, SCSI_EH_CANCEL_CMD) ||
		    SCSI_SENSE_VALID(scmd))
			continue;

		SCSI_LOG_ERROR_RECOVERY(2, printk("%s: requesting sense"
						  " for id: %d\n",
						  current->comm,
						  scmd->device->id));
		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);
}

/**
 * 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)
{
	unsigned long flags;
	int rtn = FAILED;

	if (!scmd->device->host->hostt->eh_abort_handler)
		return rtn;

	/*
	 * 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;

	scmd->owner = SCSI_OWNER_LOWLEVEL;

	spin_lock_irqsave(scmd->device->host->host_lock, flags);
	rtn = scmd->device->host->hostt->eh_abort_handler(scmd);
	spin_unlock_irqrestore(scmd->device->host->host_lock, flags);

	return rtn;
}

/**
 * scsi_eh_tur - Send TUR to device.
 * @scmd:	Scsi cmd 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:
	memcpy(scmd->cmnd, tur_command, sizeof(tur_command));

	/*
	 * zero the sense buffer.  the scsi spec mandates that any
	 * untransferred sense data should be interpreted as being zero.
	 */
	memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));

	scmd->request_buffer = NULL;
	scmd->request_bufflen = 0;
	scmd->use_sg = 0;
	scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
	scmd->underflow = 0;
	scmd->sc_data_direction = DMA_NONE;

	rtn = scsi_send_eh_cmnd(scmd, SENSE_TIMEOUT);

	/*
	 * when we eventually call scsi_finish, we really wish to complete
	 * the original request, so let's restore the original data. (db)
	 */
	scsi_setup_cmd_retry(scmd);

	/*
	 * hey, we are done.  let's look to see what happened.
	 */
	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
		__FUNCTION__, scmd, rtn));
	if (rtn == SUCCESS)
		return 0;
	else if (rtn == NEEDS_RETRY)
		if (retry_cnt--)
			goto retry_tur;
	return 1;
}

/**
 * scsi_eh_abort_cmds - abort canceled commands.
 * @shost:	scsi host being recovered.
 * @eh_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 list_head *lh, *lh_sf;
	struct scsi_cmnd *scmd;
	int rtn;

	list_for_each_safe(lh, lh_sf, work_q) {
		scmd = list_entry(lh, struct scsi_cmnd, eh_entry);
		if (!scsi_eh_eflags_chk(scmd, 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) {
			scsi_eh_eflags_clr(scmd,  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_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)
{
	unsigned long flags;
	int rtn = FAILED;

	if (!scmd->device->host->hostt->eh_device_reset_handler)
		return rtn;

	scmd->owner = SCSI_OWNER_LOWLEVEL;

	spin_lock_irqsave(scmd->device->host->host_lock, flags);
	rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
	spin_unlock_irqrestore(scmd->device->host->host_lock, flags);

	if (rtn == SUCCESS) {
		scmd->device->was_reset = 1;
		scmd->device->expecting_cc_ua = 1;
	}

	return rtn;
}

/**
 * scsi_eh_try_stu - Send START_UNIT to device.
 * @scmd:	Scsi cmd 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};
	int rtn;

	if (!scmd->device->allow_restart)
		return 1;

	memcpy(scmd->cmnd, stu_command, sizeof(stu_command));

	/*
	 * zero the sense buffer.  the scsi spec mandates that any
	 * untransferred sense data should be interpreted as being zero.
	 */
	memset(scmd->sense_buffer, 0, sizeof(scmd->sense_buffer));

	scmd->request_buffer = NULL;
	scmd->request_bufflen = 0;
	scmd->use_sg = 0;
	scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
	scmd->underflow = 0;
	scmd->sc_data_direction = DMA_NONE;

	rtn = scsi_send_eh_cmnd(scmd, START_UNIT_TIMEOUT);

	/*
	 * when we eventually call scsi_finish, we really wish to complete
	 * the original request, so let's restore the original data. (db)
	 */
	scsi_setup_cmd_retry(scmd);

	/*
	 * hey, we are done.  let's look to see what happened.
	 */
	SCSI_LOG_ERROR_RECOVERY(3, printk("%s: scmd %p rtn %x\n",
		__FUNCTION__, scmd, rtn));
	if (rtn == SUCCESS)
		return 0;
	return 1;
}

 /**
 * scsi_eh_stu - send START_UNIT if needed
 * @shost:	scsi host being recovered.
 * @eh_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 list_head *lh, *lh_sf;
	struct scsi_cmnd *scmd, *stu_scmd;