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diff --git a/share/man/man9/g_consumer.9 b/share/man/man9/g_consumer.9 new file mode 100644 index 000000000000..e30fb80280b5 --- /dev/null +++ b/share/man/man9/g_consumer.9 @@ -0,0 +1,137 @@ +.\" +.\" 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 . |