man/man9f/rmfree.9f

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 RMFREE 9F "Jan 16, 2006"
 NAME
rmfree - free space back into a resource map
 SYNOPSIS

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


void rmfree(struct map *mp, size_t size, ulong_t index);


 INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).
 PARAMETERS
mp

Pointer to the map structure.


size

Number of units being freed.


index

Index of the first unit of the allocated resource.


 DESCRIPTION

The rmfree() function releases space back into a resource map. It is the
opposite of rmalloc(9F), which allocates space that is controlled by a
resource map structure.

When releasing resources using rmfree() the size and index passed to
rmfree() must exactly match the size and index values passed to and
returned from a previous call to rmalloc(). Resources cannot be returned
piecemeal.

Drivers may define resource maps for resource allocation, in terms of arbitrary
units, using the rmallocmap(9F) function. The system maintains the
resource map structure by size and index, computed in units appropriate for the
resource. For example, units may be byte addresses, pages of memory, or blocks.
rmfree() frees up unallocated space for re-use.

The rmfree() function can also be used to initialize a resource map, in
which case the size and index should cover the entire resource area.
 CONTEXT

The rmfree() function can be called from user, interrupt, or kernel
context.
 SEE ALSO

rmalloc(9F), rmalloc_wait(9F), rmallocmap(9F),
rmfreemap(9F)

Writing Device Drivers