vm_map_find9
Find a free region within a map, and optionally map a vm_object
Usage
#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_map.h>
int
vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset, vm_offset_t *addr, vm_size_t length, boolean_t find_space, vm_prot_t prot, vm_prot_t max, int cow);
Overview
The vm_map_find() function attempts to find a free region in the target map, with the given length, and will also optionally create a mapping of object.
The arguments offset, prot, max, and cow are passed unchanged to vm_map_insert(9) when creating the mapping, if and only if a free region is found.
If object is non-NULL, the reference count on the object must be incremented by the caller before calling this function to account for the new entry.
If find_space is TRUE, the function will call vm_map_findspace(9) to discover a free region.
Implementation notes
This function acquires a lock on map by calling vm_map_lock(9), and holds it until the function returns.
The search for a free region is defined to be first-fit, from the address addr onwards.
Return values
The vm_map_find() function returns KERN_SUCCESS if space for the mapping could be found and the mapping was successfully created. If space could not be found in the map, KERN_NO_SPACE will be returned. If the discovered range turned out to be bogus, KERN_INVALID_ADDRESS will be returned.