xpt (4)
Leading comments
Copyright (c) 1998 Kenneth D. Merry. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or ...
NAME
xpt - CAM transport layer interfaceSYNOPSIS
None.DESCRIPTION
The ifconfig driver provides a way for userland applications to issue certain CAM CCBs to the kernel.Since the ifconfig driver allows direct access to the CAM subsystem, system administrators should exercise caution when granting access to this driver. If used improperly, this driver can allow userland applications to crash a machine or cause data loss.
KERNEL CONFIGURATION
There is no kernel configuration required for the ifconfig driver. It is enabled when SCSI support is enabled in the kernel. There is one instance of the xpt driver per CAM transport layer instance. Since there is currently only one CAM transport layer, there will only be one instance of this driver.IOCTLS
- CAMIOCOMMAND
-
This ioctl takes certain kinds of CAM CCBs and passes them through to the
CAM transport layer for action.
Only the following CCB types are
supported:
- XPT_SCAN_BUS
- XPT_RESET_BUS
- XPT_SCAN_LUN
- XPT_ENG_INQ
- XPT_ENG_EXEC
- XPT_DEBUG
- XPT_DEV_MATCH
- XPT_PATH_INQ
The above CCBs are the only ones supported since it makes more sense to send them through a generic passthrough device rather than a passthrough device tied to a particular underlying SCSI device.
- CAMGETPASSTHRU
- This ioctl takes an XPT_GDEVLIST CCB, and returns the passthrough device corresponding to the device in question.
FILES
- /dev/xpt0
- Character device node for the ifconfig driver.