scsi_scan.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,352 行 · 第 1/3 页

static int scsilun_to_int(struct scsi_lun *scsilun)
{
	int i;
	unsigned int lun;

	lun = 0;
	for (i = 0; i < sizeof(lun); i += 2)
		lun = lun | (((scsilun->scsi_lun[i] << 8) |
			      scsilun->scsi_lun[i + 1]) << (i * 8));
	return lun;
}

/**
 * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
 * @sdevscan:	scan the host, channel, and id of this Scsi_Device
 *
 * Description:
 *     If @sdevscan is for a SCSI-3 or up device, send a REPORT LUN
 *     command, and scan the resulting list of LUNs by calling
 *     scsi_probe_and_add_lun.
 *
 *     Modifies sdevscan->lun.
 *
 * Return:
 *     0: scan completed (or no memory, so further scanning is futile)
 *     1: no report lun scan, or not configured
 **/
static int scsi_report_lun_scan(struct scsi_device *sdev, int bflags,
				int rescan)
{
	char devname[64];
	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
	unsigned int length;
	unsigned int lun;
	unsigned int num_luns;
	unsigned int retries;
	struct scsi_lun *lunp, *lun_data;
	struct scsi_request *sreq;
	u8 *data;

	/*
	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
	 * support more than 8 LUNs.
	 */
	if ((bflags & BLIST_NOREPORTLUN) || 
	     sdev->scsi_level < SCSI_2 ||
	    (sdev->scsi_level < SCSI_3 && 
	     (!(bflags & BLIST_REPORTLUN2) || sdev->host->max_lun <= 8)) )
		return 1;
	if (bflags & BLIST_NOLUN)
		return 0;

	sreq = scsi_allocate_request(sdev, GFP_ATOMIC);
	if (!sreq)
		goto out;

	sprintf(devname, "host %d channel %d id %d",
		sdev->host->host_no, sdev->channel, sdev->id);

	/*
	 * Allocate enough to hold the header (the same size as one scsi_lun)
	 * plus the max number of luns we are requesting.
	 *
	 * Reallocating and trying again (with the exact amount we need)
	 * would be nice, but then we need to somehow limit the size
	 * allocated based on the available memory and the limits of
	 * kmalloc - we don't want a kmalloc() failure of a huge value to
	 * prevent us from finding any LUNs on this target.
	 */
	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
	lun_data = kmalloc(length, GFP_ATOMIC |
			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
	if (!lun_data)
		goto out_release_request;

	scsi_cmd[0] = REPORT_LUNS;

	/*
	 * bytes 1 - 5: reserved, set to zero.
	 */
	memset(&scsi_cmd[1], 0, 5);

	/*
	 * bytes 6 - 9: length of the command.
	 */
	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
	scsi_cmd[9] = (unsigned char) length & 0xff;

	scsi_cmd[10] = 0;	/* reserved */
	scsi_cmd[11] = 0;	/* control */
	sreq->sr_cmd_len = 0;
	sreq->sr_data_direction = DMA_FROM_DEVICE;

	/*
	 * We can get a UNIT ATTENTION, for example a power on/reset, so
	 * retry a few times (like sd.c does for TEST UNIT READY).
	 * Experience shows some combinations of adapter/devices get at
	 * least two power on/resets.
	 *
	 * Illegal requests (for devices that do not support REPORT LUNS)
	 * should come through as a check condition, and will not generate
	 * a retry.
	 */
	for (retries = 0; retries < 3; retries++) {
		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
				" REPORT LUNS to %s (try %d)\n", devname,
				retries));
		scsi_wait_req(sreq, scsi_cmd, lun_data, length,
				SCSI_TIMEOUT + 4*HZ, 3);
		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
				" %s (try %d) result 0x%x\n", sreq->sr_result
				?  "failed" : "successful", retries,
				sreq->sr_result));
		if (sreq->sr_result == 0 ||
		    sreq->sr_sense_buffer[2] != UNIT_ATTENTION)
			break;
	}

	if (sreq->sr_result) {
		/*
		 * The device probably does not support a REPORT LUN command
		 */
		kfree(lun_data);
		scsi_release_request(sreq);
		return 1;
	}
	scsi_release_request(sreq);

	/*
	 * Get the length from the first four bytes of lun_data.
	 */
	data = (u8 *) lun_data->scsi_lun;
	length = ((data[0] << 24) | (data[1] << 16) |
		  (data[2] << 8) | (data[3] << 0));

	num_luns = (length / sizeof(struct scsi_lun));
	if (num_luns > max_scsi_report_luns) {
		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
		       " of %d luns reported, try increasing"
		       " max_scsi_report_luns.\n", devname,
		       max_scsi_report_luns, num_luns);
		num_luns = max_scsi_report_luns;
	}

	SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUN scan of"
			" host %d channel %d id %d\n", sdev->host->host_no,
			sdev->channel, sdev->id));

	/*
	 * Scan the luns in lun_data. The entry at offset 0 is really
	 * the header, so start at 1 and go up to and including num_luns.
	 */
	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
		lun = scsilun_to_int(lunp);

		/*
		 * Check if the unused part of lunp is non-zero, and so
		 * does not fit in lun.
		 */
		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
			int i;

			/*
			 * Output an error displaying the LUN in byte order,
			 * this differs from what linux would print for the
			 * integer LUN value.
			 */
			printk(KERN_WARNING "scsi: %s lun 0x", devname);
			data = (char *)lunp->scsi_lun;
			for (i = 0; i < sizeof(struct scsi_lun); i++)
				printk("%02x", data[i]);
			printk(" has a LUN larger than currently supported.\n");
		} else if (lun == 0) {
			/*
			 * LUN 0 has already been scanned.
			 */
		} else if (lun > sdev->host->max_lun) {
			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
			       " than allowed by the host adapter\n",
			       devname, lun);
		} else {
			int res;

			res = scsi_probe_and_add_lun(sdev->host, sdev->channel,
				sdev->id, lun, NULL, NULL, rescan, NULL);
			if (res == SCSI_SCAN_NO_RESPONSE) {
				/*
				 * Got some results, but now none, abort.
				 */
				printk(KERN_ERR "scsi: Unexpected response"
				       " from %s lun %d while scanning, scan"
				       " aborted\n", devname, lun);
				break;
			}
		}
	}

	kfree(lun_data);
	return 0;

 out_release_request:
	scsi_release_request(sreq);
 out:
	/*
	 * We are out of memory, don't try scanning any further.
	 */
	printk(ALLOC_FAILURE_MSG, __FUNCTION__);
	return 0;
}

struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
		uint id, uint lun, void *hostdata)
{
	struct scsi_device *sdev;
	int res;

	down(&shost->scan_mutex);
	res = scsi_probe_and_add_lun(shost, channel, id, lun, NULL,
				     &sdev, 1, hostdata);
	if (res != SCSI_SCAN_LUN_PRESENT)
		sdev = ERR_PTR(-ENODEV);
	up(&shost->scan_mutex);

	return sdev;
}

void scsi_rescan_device(struct device *dev)
{
	struct scsi_driver *drv;
	
	if (!dev->driver)
		return;

	drv = to_scsi_driver(dev->driver);
	if (try_module_get(drv->owner)) {
		if (drv->rescan)
			drv->rescan(dev);
		module_put(drv->owner);
	}
}

/**
 * scsi_scan_target - scan a target id, possibly including all LUNs on the
 *     target.
 * @sdevsca:	Scsi_Device handle for scanning
 * @shost:	host to scan
 * @channel:	channel to scan
 * @id:		target id to scan
 *
 * Description:
 *     Scan the target id on @shost, @channel, and @id. Scan at least LUN
 *     0, and possibly all LUNs on the target id.
 *
 *     Use the pre-allocated @sdevscan as a handle for the scanning. This
 *     function sets sdevscan->host, sdevscan->id and sdevscan->lun; the
 *     scanning functions modify sdevscan->lun.
 *
 *     First try a REPORT LUN scan, if that does not scan the target, do a
 *     sequential scan of LUNs on the target id.
 **/
static void scsi_scan_target(struct Scsi_Host *shost, unsigned int channel,
			     unsigned int id, unsigned int lun, int rescan)
{
	int bflags = 0;
	int res;
	struct scsi_device *sdev;

	if (shost->this_id == id)
		/*
		 * Don't scan the host adapter
		 */
		return;

	if (lun != SCAN_WILD_CARD) {
		/*
		 * Scan for a specific host/chan/id/lun.
		 */
		scsi_probe_and_add_lun(shost, channel, id, lun, NULL, NULL,
				       rescan, NULL);
		return;
	}

	/*
	 * Scan LUN 0, if there is some response, scan further. Ideally, we
	 * would not configure LUN 0 until all LUNs are scanned.
	 */
	res = scsi_probe_and_add_lun(shost, channel, id, 0, &bflags, &sdev,
				     rescan, NULL);
	if (res == SCSI_SCAN_LUN_PRESENT) {
		if (scsi_report_lun_scan(sdev, bflags, rescan) != 0)
			/*
			 * The REPORT LUN did not scan the target,
			 * do a sequential scan.
			 */
			scsi_sequential_lun_scan(shost, channel, id, bflags,
				       	res, sdev->scsi_level, rescan);
	} else if (res == SCSI_SCAN_TARGET_PRESENT) {
		/*
		 * There's a target here, but lun 0 is offline so we
		 * can't use the report_lun scan.  Fall back to a
		 * sequential lun scan with a bflags of SPARSELUN and
		 * a default scsi level of SCSI_2
		 */
		scsi_sequential_lun_scan(shost, channel, id, BLIST_SPARSELUN,
				SCSI_SCAN_TARGET_PRESENT, SCSI_2, rescan);
	}
}

static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
			      unsigned int id, unsigned int lun, int rescan)
{
	uint order_id;

	if (id == SCAN_WILD_CARD)
		for (id = 0; id < shost->max_id; ++id) {
			/*
			 * XXX adapter drivers when possible (FCP, iSCSI)
			 * could modify max_id to match the current max,
			 * not the absolute max.
			 *
			 * XXX add a shost id iterator, so for example,
			 * the FC ID can be the same as a target id
			 * without a huge overhead of sparse id's.
			 */
			if (shost->reverse_ordering)
				/*
				 * Scan from high to low id.
				 */
				order_id = shost->max_id - id - 1;
			else
				order_id = id;
			scsi_scan_target(shost, channel, order_id, lun, rescan);
		}
	else
		scsi_scan_target(shost, channel, id, lun, rescan);
}

int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
			    unsigned int id, unsigned int lun, int rescan)
{
	SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "%s: <%u:%u:%u:%u>\n",
		__FUNCTION__, shost->host_no, channel, id, lun));

	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
	    ((id != SCAN_WILD_CARD) && (id > shost->max_id)) ||
	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
		return -EINVAL;

	down(&shost->scan_mutex);
	if (channel == SCAN_WILD_CARD) 
		for (channel = 0; channel <= shost->max_channel; channel++)
			scsi_scan_channel(shost, channel, id, lun, rescan);
	else
		scsi_scan_channel(shost, channel, id, lun, rescan);
	up(&shost->scan_mutex);

	return 0;
}

/**
 * scsi_scan_host - scan the given adapter
 * @shost:	adapter to scan
 **/
void scsi_scan_host(struct Scsi_Host *shost)
{
	scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
				SCAN_WILD_CARD, 0);
}

void scsi_forget_host(struct Scsi_Host *shost)
{
	struct scsi_device *sdev, *tmp;
	unsigned long flags;

	/*
	 * Ok, this look a bit strange.  We always look for the first device
	 * on the list as scsi_remove_device removes them from it - thus we
	 * also have to release the lock.
	 * We don't need to get another reference to the device before
	 * releasing the lock as we already own the reference from
	 * scsi_register_device that's release in scsi_remove_device.  And
	 * after that we don't look at sdev anymore.
	 */
	spin_lock_irqsave(shost->host_lock, flags);
	list_for_each_entry_safe(sdev, tmp, &shost->__devices, siblings) {
		spin_unlock_irqrestore(shost->host_lock, flags);
		scsi_remove_device(sdev);
		spin_lock_irqsave(shost->host_lock, flags);
	}
	spin_unlock_irqrestore(shost->host_lock, flags);
}

/*
 * Function:    scsi_get_host_dev()
 *
 * Purpose:     Create a Scsi_Device that points to the host adapter itself.
 *
 * Arguments:   SHpnt   - Host that needs a Scsi_Device
 *
 * Lock status: None assumed.
 *
 * Returns:     The Scsi_Device or NULL
 *
 * Notes:
 *	Attach a single Scsi_Device to the Scsi_Host - this should
 *	be made to look like a "pseudo-device" that points to the
 *	HA itself.
 *
 *	Note - this device is not accessible from any high-level
 *	drivers (including generics), which is probably not
 *	optimal.  We can add hooks later to attach 
 */
struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
{
	struct scsi_device *sdev;

	sdev = scsi_alloc_sdev(shost, 0, shost->this_id, 0, NULL);
	if (sdev) {
		sdev->borken = 0;
	}
	return sdev;
}

/*
 * Function:    scsi_free_host_dev()
 *
 * Purpose:     Free a scsi_device that points to the host adapter itself.
 *
 * Arguments:   SHpnt   - Host that needs a Scsi_Device
 *
 * Lock status: None assumed.
 *
 * Returns:     Nothing
 *
 * Notes:
 */
void scsi_free_host_dev(struct scsi_device *sdev)
{
	BUG_ON(sdev->id != sdev->host->this_id);

	if (sdev->host->hostt->slave_destroy)
		sdev->host->hostt->slave_destroy(sdev);
	if (sdev->host->transportt->cleanup)
		sdev->host->transportt->cleanup(sdev);
	put_device(&sdev->sdev_gendev);
}