rmallocmap_wait(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  alloca-
     tions 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 allo-
     cation, 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 subse-
     quent   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,  ker-
     nel, 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