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DECLARE_GEOM_CLASS(9FREEBSD) - Linux manual page online | System kernel interfaces

GEOM class declaration macro.

August 13, 2007


DECLARE_GEOM_CLASS — GEOM class declaration macro


#include <geom/geom.h> DECLARE_GEOM_CLASS(class, mod_name);


The DECLARE_GEOM_CLASS() macro registers a GEOM class in GEOM. A GEOM class itself imple‐ ments one particular kind of transformation. Typical examples are: MBR disk partition, BSD disklabel and RAID5 classes. DECLARE_GEOM_CLASS() can be used both for compiled in and loaded as kld(4) modules GEOM classes and it is the only official way for class registra‐ tion. The arguments to DECLARE_GEOM_CLASS() are: class The g_class structure which describes a GEOM class. mod_name A kernel module name (not a class name!). Structure g_class contains data describing the class. They are: const char * name Class name. g_taste_t * taste Pointer to function used for taste event handling. If it is non-NULL it is called in three situations: - On class activation, all existing providers are offered for tasting. - When new provider is created it is offered for tasting. - After last write access to a provider is closed it is offered for retast‐ ing (on first write open event “spoil” was sent). g_config_t * config This field is not used anymore, its functionality was replaced by the ctlreq field. g_ctl_req_t * ctlreq Pointer to function used for handling events from userland applications. g_init_t * init Pointer to function which is called right after class registration. g_fini_t * fini Pointer to function which is called right before class deregistration. g_ctl_destroy_geom_t * destroy_geom Pointer to a function which is called for every geom on class unload. If this field is not set, the class can not be unloaded. Only a name field is required; the rest are optional. RESTRICTIONS/CONDITIONS The fields of g_class should always be initialized using C99-style field naming (see the initialization of example_class below).


Example class declaration. static struct g_geom * g_example_taste(struct g_class *mp, struct g_provider *pp, int flags __unused) { g_topology_assert(); [...] } static void g_example_ctlreq(struct gctl_req *req, struct g_class *cp, char const *verb) { [...] } static int g_example_destroy_geom(struct gctl_req *req, struct g_class *cp, struct g_geom *gp) { g_topology_assert(); [...] } static void g_example_init(struct g_class *mp) { [...] } static void g_example_fini(struct g_class *mp) { [...] } struct g_class example_class = { .name = "EXAMPLE", .taste = g_example_taste, .ctlreq = g_example_ctlreq, .init = g_example_init, .fini = g_example_fini, .destroy_geom = g_example_destroy_geom }; DECLARE_GEOM_CLASS(example_class, g_example);


geom(4), g_attach(9), g_bio(9), g_consumer(9), g_data(9), g_event(9), g_geom(9), g_provider(9), g_provider_by_name(9), g_wither_geom(9)


This manual page was written by Pawel Jakub Dawidek <>.
BSD August 13, 2007 BSD
This manual Reference Other manuals
DECLARE_GEOM_CLASS(9freebsd) referred by g_access(9freebsd) | g_alloc_bio(9freebsd) | g_attach(9freebsd) | g_bio(9freebsd) | g_cancel_event(9freebsd) | g_clone_bio(9freebsd) | g_consumer(9freebsd) | g_data(9freebsd) | g_destroy_bio(9freebsd) | g_destroy_consumer(9freebsd) | g_destroy_geom(9freebsd) | g_destroy_provider(9freebsd) | g_detach(9freebsd) | g_duplicate_bio(9freebsd) | g_error_provider(9freebsd) | g_event(9freebsd) | g_geom(9freebsd) | g_new_bio(9freebsd) | g_new_consumer(9freebsd) | g_new_geomf(9freebsd)
refer to g_attach(9freebsd) | g_bio(9freebsd) | g_consumer(9freebsd) | g_data(9freebsd) | g_event(9freebsd) | g_geom(9freebsd) | g_provider(9freebsd) | g_provider_by_name(9freebsd) | g_wither_geom(9freebsd) | kld(4freebsd)
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