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transfer_area() now reserves the address range of the old area after removing

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it, so that it can guarantee readding it again, in case the transfer is failing.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@11173 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2005-01-31 18:36:05 +00:00
parent 54c34e6829
commit b18fc6654c
1 changed files with 29 additions and 11 deletions
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40
src/kernel/core/vm/vm.c
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@ -2953,9 +2953,7 @@ out:
/** Transfers the specified area to a new team. The caller must be the owner
* of the area (not yet enforced).
* If the transfer fails for whatever reason, the area may have been relocated
* in the owning team, or even deleted if the relocation failed.
* of the area (not yet enforced but probably should be).
* This function is currently not exported to the kernel namespace, but is
* only accessible using the _kern_transfer_area() syscall.
*/
@ -2965,7 +2963,8 @@ transfer_area(area_id id, void **_address, uint32 addressSpec, team_id target)
{
vm_address_space *sourceAddressSpace, *targetAddressSpace;
vm_translation_map *map;
vm_area *area;
vm_area *area, *reserved;
void *reservedAddress;
status_t status;
area = vm_get_area(id);
@ -2978,8 +2977,26 @@ transfer_area(area_id id, void **_address, uint32 addressSpec, team_id target)
if (status != B_OK)
goto err1;
// We will first remove the area, and then reserve its former
// address range so that we can later reclaim it if the
// transfer failed.
sourceAddressSpace = area->aspace;
remove_area_from_virtual_map(sourceAddressSpace, area, false);
reserved = _vm_create_reserved_region_struct(&sourceAddressSpace->virtual_map);
if (reserved == NULL) {
status = B_NO_MEMORY;
goto err2;
}
acquire_sem_etc(sourceAddressSpace->virtual_map.sem, WRITE_COUNT, 0, 0);
reservedAddress = (void *)area->base;
remove_area_from_virtual_map(sourceAddressSpace, area, true);
insert_area(sourceAddressSpace, &reservedAddress, B_EXACT_ADDRESS, area->size, reserved);
// famous last words: this cannot fail :)
release_sem_etc(sourceAddressSpace->virtual_map.sem, WRITE_COUNT, 0);
// unmap the area in the source address space
map = &sourceAddressSpace->translation_map;
@ -2995,18 +3012,19 @@ transfer_area(area_id id, void **_address, uint32 addressSpec, team_id target)
// okay, someone is trying to delete this aspace now, so we can't
// insert the area, so back out
status = B_BAD_TEAM_ID;
goto err2;
goto err3;
}
status = insert_area(targetAddressSpace, _address, addressSpec, area->size, area);
if (status < B_OK)
goto err2;
goto err3;
// The area was successfully transferred to the new team when we got here
area->aspace = targetAddressSpace;
release_sem_etc(targetAddressSpace->virtual_map.sem, WRITE_COUNT, 0);
vm_unreserve_address_range(sourceAddressSpace->id, reservedAddress, area->size);
vm_put_aspace(sourceAddressSpace);
// we keep the reference of the target address space for the
// area, so we only have to put the one from the source
@ -3014,15 +3032,14 @@ transfer_area(area_id id, void **_address, uint32 addressSpec, team_id target)
return B_OK;
err2:
err3:
release_sem_etc(targetAddressSpace->virtual_map.sem, WRITE_COUNT, 0);
vm_put_aspace(targetAddressSpace);
// insert the area again into the source address space
acquire_sem_etc(sourceAddressSpace->virtual_map.sem, WRITE_COUNT, 0, 0);
// check to see if this aspace has entered DELETE state
if (sourceAddressSpace->state == VM_ASPACE_STATE_DELETION
|| insert_area(sourceAddressSpace, _address, B_ANY_ADDRESS, area->size, area) != B_OK) {
|| insert_area(sourceAddressSpace, &reservedAddress, B_EXACT_ADDRESS, area->size, area) != B_OK) {
// We can't insert the area anymore - we have to delete it manually
vm_cache_remove_area(area->cache_ref, area);
vm_cache_release_ref(area->cache_ref);
@ -3031,7 +3048,8 @@ err2:
area = NULL;
}
release_sem_etc(sourceAddressSpace->virtual_map.sem, WRITE_COUNT, 0);
err2:
vm_put_aspace(targetAddressSpace);
err1:
if (area != NULL)
vm_put_area(area);