OpenBSD-4.6/share/man/man9/bio_register.9

.\"	$OpenBSD: bio_register.9,v 1.4 2008/04/03 00:23:33 weingart Exp $
.\"
.\" Copyright (c) 2006 David Gwynne <dlg@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: April 3 2008 $
.Dt BIO_REGISTER 9
.Os
.Sh NAME
.Nm bio_register ,
.Nm bio_unregister
.Nd block I/O ioctl tunnelling interface
.Sh SYNOPSIS
.In dev/biovar.h
.Ft int
.Fn bio_register "struct device *dev" "int (*bioctl)(struct device *, u_long, caddr_t)"
.Fn bio_unregister "struct device *dev"
.Sh DESCRIPTION
The block I/O ioctl tunnelling interface is used by drivers to register and
unregister ioctl handlers to be accessed via the
.Xr bio 4
device.
.Pp
.Fn bio_register
is called by the driver represented by
.Fa dev
to register the
.Fa bioctl
argument as the ioctl handler for itself.
.Pp
.Fn bio_unregister
is called to remove the ioctl handler previously registered with
.Fn bio_register
for the device represented by
.Fa dev .
.Pp
.Fn bio_register
and
.Fn bio_unregister
can be called during
.Xr autoconf 9
or from process context.
The
.Fa bioctl
callback is called from process context.
.Sh SEE ALSO
.Xr bio 4 ,
.Xr autoconf 9
.Sh HISTORY
The block I/O ioctl tunnelling interface first appeared in
.Ox 3.2 .
.Sh AUTHORS
The block I/O ioctl tunnelling interface was written by
.An Niklas Hallqvist Aq niklas@openbsd.org .