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XPT(4)		       FreeBSD Kernel Interfaces Manual			XPT(4)

NAME
     xpt -- CAM	transport layer	interface

SYNOPSIS
     None.

DESCRIPTION
     The xpt driver provides a way for userland	applications to	issue certain
     CAM CCBs to the kernel.

     Since the xpt 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 xpt 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 partic-
		     ular underlying SCSI device.

     CAMGETPASSTHRU  This ioctl	takes an XPT_GDEVLIST CCB, and returns the
		     passthrough device	corresponding to the device in ques-
		     tion.

FILES
     /dev/xpt0	Character device node for the xpt driver.

DIAGNOSTICS
     None.

SEE ALSO
     cam(3), cam_cdbparse(3), pass(4), camcontrol(8)

HISTORY
     The CAM transport layer driver first appeared in FreeBSD 3.0.

AUTHORS
     Kenneth Merry <ken@FreeBSD.org>

FreeBSD	10.1		       October 10, 1998			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | KERNEL CONFIGURATION | IOCTLS | FILES | DIAGNOSTICS | SEE ALSO | HISTORY | AUTHORS

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