mirror of
https://github.com/freebsd/freebsd-src.git
synced 2024-12-04 16:49:40 +00:00
138 lines
3.7 KiB
Groff
138 lines
3.7 KiB
Groff
.\"
|
|
.\" Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
|
|
.\" 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 other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR
|
|
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd January 16, 2004
|
|
.Dt G_CONSUMER 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm g_new_consumer ,
|
|
.Nm g_destroy_consumer
|
|
.Nd "GEOM consumers management"
|
|
.Sh SYNOPSIS
|
|
.In geom/geom.h
|
|
.Ft "struct g_consumer *"
|
|
.Fn g_new_consumer "struct g_geom *gp"
|
|
.Ft void
|
|
.Fn g_destroy_consumer "struct g_consumer *cp"
|
|
.Sh DESCRIPTION
|
|
A GEOM consumer is the backdoor through which a geom connects to
|
|
another GEOM provider and through which I/O requests are sent.
|
|
.Pp
|
|
The
|
|
.Fn g_new_consumer
|
|
function creates a new consumer on geom
|
|
.Fa gp .
|
|
Before using the new consumer, it has to be attached to a provider with
|
|
.Xr g_attach 9
|
|
and opened with
|
|
.Xr g_access 9 .
|
|
.Pp
|
|
The
|
|
.Fn g_destroy_consumer
|
|
function destroys the given consumer and cancels all related pending events.
|
|
This function is the last stage of killing an unwanted consumer.
|
|
.Sh RESTRICTIONS/CONDITIONS
|
|
.Fn g_new_consumer :
|
|
.Bl -item -offset indent
|
|
.It
|
|
The geom
|
|
.Fa gp
|
|
has to have an
|
|
.Va orphan
|
|
method defined.
|
|
.It
|
|
The topology lock has to be held.
|
|
.El
|
|
.Pp
|
|
.Fn g_destroy_consumer :
|
|
.Bl -item -offset indent
|
|
.It
|
|
The consumer must not be attached to a provider.
|
|
.It
|
|
The access count has to be 0.
|
|
.It
|
|
The topology lock has to be held.
|
|
.El
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn g_new_consumer
|
|
function
|
|
returns a pointer to the newly created consumer.
|
|
.Sh EXAMPLES
|
|
Create consumer, attach it to given provider, gain read access and clean up.
|
|
.Bd -literal -offset indent
|
|
void
|
|
some_function(struct g_geom *mygeom, struct g_provider *pp)
|
|
{
|
|
struct g_consumer *cp;
|
|
|
|
g_topology_assert();
|
|
|
|
/* Create new consumer on 'mygeom' geom. */
|
|
cp = g_new_consumer(mygeom);
|
|
/* Attach newly created consumer to given provider. */
|
|
if (g_attach(cp, pp) != 0) {
|
|
g_destroy_consumer(cp);
|
|
return;
|
|
}
|
|
/* Open provider for reading through our consumer. */
|
|
if (g_access(cp, 1, 0, 0) != 0) {
|
|
g_detach(cp);
|
|
g_destroy_consumer(cp);
|
|
return;
|
|
}
|
|
|
|
g_topology_unlock();
|
|
/*
|
|
* Read data from provider.
|
|
*/
|
|
g_topology_lock();
|
|
|
|
/* Disconnect from provider (release access count). */
|
|
g_access(cp, -1, 0, 0);
|
|
/* Detach from provider. */
|
|
g_detach(cp);
|
|
/* Destroy consumer. */
|
|
g_destroy_consumer(cp);
|
|
}
|
|
.Ed
|
|
.Sh SEE ALSO
|
|
.Xr geom 4 ,
|
|
.Xr DECLARE_GEOM_CLASS 9 ,
|
|
.Xr g_access 9 ,
|
|
.Xr g_attach 9 ,
|
|
.Xr g_bio 9 ,
|
|
.Xr g_data 9 ,
|
|
.Xr g_event 9 ,
|
|
.Xr g_geom 9 ,
|
|
.Xr g_provider 9 ,
|
|
.Xr g_provider_by_name 9 ,
|
|
.Xr g_wither_geom 9
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
This manual page was written by
|
|
.An Pawel Jakub Dawidek Aq pjd@FreeBSD.org .
|