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g_consumer.9freebsd
Langue: en
Version: 307358 (debian - 07/07/09)
Section: 9 (Appels noyau Linux)
BSD mandoc
NAME
g_new_consumer g_destroy_consumer - GEOM consumers managementSYNOPSIS
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 *cpDESCRIPTION
A GEOM consumer is the backdoor through which a geom connects to another GEOM provider and through which I/O requests are sent.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 g_attach9 and opened with g_access9.
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.
RESTRICTIONS/CONDITIONS
Fn g_new_consumer :- The geom
- Fa gp has to have an orphan method defined.
- The topology lock has to be held.
Fn g_destroy_consumer :
- The consumer must not be attached to a provider.
- The access count has to be 0.
- The topology lock has to be held.
RETURN VALUES
The Fn g_new_consumer function returns a pointer to the newly created consumer.EXAMPLES
Create consumer, attach it to given provider, gain read access and clean up.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); }
SEE ALSO
geom(4), DECLARE_GEOM_CLASS9, g_access9, g_attach9, g_bio9, g_data9, g_event9, g_geom9, g_provider9, g_provider_by_name9, g_wither_geom9AUTHORS
An -nosplit This manual page was written by An Pawel Jakub Dawidek Aq pjd@FreeBSD.org .Contenus ©2006-2024 Benjamin Poulain
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