* Removed the ref_count from vm_areas. You now always need to have the address
space locked (read or write, depending on what you do) when dealing with
areas.
* Added helper classes for locking the address space: AddressSpace{Read|Write}Locker,
and MultiAddressSpaceLocker which can lock several spaces at once and makes
sure no dead locks can happen.
* resize_area() is now using the MultiAddressSpaceLocker instead of no locking
at all; ie. it should now be safely to use.
* Disabled transfer_area() for now; it will be changed to work like an atomic
clone_area()/delete_area(), that is, it will hand out a new ID for the
transfered area.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@21848 a95241bf-73f2-0310-859d-f6bbb57e9c96
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