RMALLOCMAP(9F) Kernel Functions for Drivers RMALLOCMAP(9F)

NAME

rmallocmap, rmallocmap_wait, rmfreemap - allocate and free resource maps

SYNOPSIS

#include <sys/ddi.h>
#include <sys/sunddi.h>


struct map *rmallocmap(size_t mapsize);


struct map *rmallocmap_wait(size_t mapsize);


void rmfreemap(struct map *mp);

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).

PARAMETERS

mapsize
Number of entries for the map.


mp
A pointer to the map structure to be deallocated.

DESCRIPTION

rmallocmap() dynamically allocates a resource map structure. The argument
mapsize defines the total number of entries in the map. In particular,
it is the total number of allocations that can be outstanding at any one
time.


rmallocmap() initializes the map but does not associate it with the
actual resource. In order to associate the map with the actual resource,
a call to rmfree(9F) is used to make the entirety of the actual resource
available for allocation, starting from the first index into the
resource. Typically, the call to rmallocmap() is followed by a call to
rmfree(9F), passing the address of the map returned from rmallocmap(),
the total size of the resource, and the first index into the actual
resource.


The resource map allocated by rmallocmap() can be used to describe an
arbitrary resource in whatever allocation units are appropriate, such as
blocks, pages, or data structures. This resource can then be managed by
the system by subsequent calls to rmalloc(9F), rmalloc_wait(9F), and
rmfree(9F).


rmallocmap_wait() is similar to rmallocmap(), with the exception that it
will wait for space to become available if necessary.


rmfreemap() deallocates a resource map structure previously allocated by
rmallocmap() or rmallocmap_wait(). The argument mp is a pointer to the
map structure to be deallocated.

RETURN VALUES

Upon successful completion, rmallocmap() and rmallocmap_wait() return a
pointer to the newly allocated map structure. Upon failure, rmallocmap()
returns a NULL pointer.

CONTEXT

rmallocmap() and rmfreemap() can be called from user, kernel, or
interrupt context.


rmallocmap_wait() can only be called from user or kernel context.

SEE ALSO

rmalloc(9F), rmalloc_wait(9F), rmfree(9F)


Writing Device Drivers

November 20, 1996 RMALLOCMAP(9F)