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Naive implementation of transfer_area(). It follows the suggested sematics

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of the resolved ToDo, but could probably be made more efficient. Instead of
transfering the area, the area is cloned into the target teams' address space
and the original is deleted. This generates a new area_id for the transfered
area (as suggested by the ToDo). Updated syscall prototypes according to the
status_t to area_id return type change.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24320 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Michael Lotz
2008-03-09 12:56:59 +00:00
parent e53032e55d
commit d1189f0b05
4 changed files with 22 additions and 109 deletions
Download Patch File Download Diff File Expand all files Collapse all files
headers/build/private/kernel/syscalls.h
+1 -1
View File
@@ -207,7 +207,7 @@ extern status_t _kern_unlock_node(int fd);
// extern status_t _kern_get_area_info(area_id area, area_info *info);
// extern status_t _kern_get_next_area_info(team_id team, int32 *cookie, area_info *info);
// extern status_t _kern_resize_area(area_id area, size_t newSize);
// extern status_t _kern_transfer_area(area_id area, void **_address, uint32 addressSpec,
// extern area_id _kern_transfer_area(area_id area, void **_address, uint32 addressSpec,
// team_id target);
// extern status_t _kern_set_area_protection(area_id area, uint32 newProtection);
// extern area_id _kern_clone_area(const char *name, void **_address, uint32 addressSpec,
headers/private/kernel/syscalls.h
+1 -1
View File
@@ -234,7 +234,7 @@ extern area_id _kern_find_area(const char *name);
extern status_t _kern_get_area_info(area_id area, area_info *info);
extern status_t _kern_get_next_area_info(team_id team, int32 *cookie, area_info *info);
extern status_t _kern_resize_area(area_id area, size_t newSize);
extern status_t _kern_transfer_area(area_id area, void **_address, uint32 addressSpec,
extern area_id _kern_transfer_area(area_id area, void **_address, uint32 addressSpec,
team_id target);
extern status_t _kern_set_area_protection(area_id area, uint32 newProtection);
extern area_id _kern_clone_area(const char *name, void **_address, uint32 addressSpec,
headers/private/kernel/vm.h
+1 -1
View File
@@ -149,7 +149,7 @@ area_id _user_find_area(const char *name);
status_t _user_get_area_info(area_id area, area_info *info);
status_t _user_get_next_area_info(team_id team, int32 *cookie, area_info *info);
status_t _user_resize_area(area_id area, size_t newSize);
status_t _user_transfer_area(area_id area, void **_address, uint32 addressSpec,
area_id _user_transfer_area(area_id area, void **_address, uint32 addressSpec,
team_id target);
status_t _user_set_area_protection(area_id area, uint32 newProtection);
area_id _user_clone_area(const char *name, void **_address, uint32 addressSpec,
src/system/kernel/vm/vm.cpp
+19 -106
View File
@@ -4978,113 +4978,26 @@ resize_area(area_id areaID, size_t newSize)
* only accessible using the _kern_transfer_area() syscall.
*/
static status_t
static area_id
transfer_area(area_id id, void **_address, uint32 addressSpec, team_id target)
{
// TODO: implement like clone_area(), just atomically (ie. hand out a new area ID)!
return B_ERROR;
#if 0
vm_address_space *sourceAddressSpace;
vm_address_space *targetAddressSpace;
void *reservedAddress = NULL;
vm_area *reserved;
vm_area *area = vm_get_area(id);
if (area == NULL)
return B_BAD_VALUE;
// ToDo: check if the current team owns the area
status_t status = team_get_address_space(target, &targetAddressSpace);
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->address_space;
reserved = create_reserved_area_struct(sourceAddressSpace, 0);
if (reserved == NULL) {
status = B_NO_MEMORY;
goto err2;
}
acquire_sem_etc(sourceAddressSpace->sem, WRITE_COUNT, 0, 0);
// unmap the area in the source address space
vm_unmap_pages(area, area->base, area->size);
// TODO: there might be additional page faults at this point!
reservedAddress = (void *)area->base;
remove_area_from_address_space(sourceAddressSpace, area);
status = insert_area(sourceAddressSpace, &reservedAddress, B_EXACT_ADDRESS,
area->size, reserved);
// famous last words: this cannot fail :)
release_sem_etc(sourceAddressSpace->sem, WRITE_COUNT, 0);
if (status != B_OK)
goto err3;
// insert the area into the target address space
acquire_sem_etc(targetAddressSpace->sem, WRITE_COUNT, 0, 0);
// check to see if this address space has entered DELETE state
if (targetAddressSpace->state == VM_ASPACE_STATE_DELETION) {
// okay, someone is trying to delete this adress space now, so we can't
// insert the area, so back out
status = B_BAD_TEAM_ID;
goto err4;
}
status = insert_area(targetAddressSpace, _address, addressSpec, area->size, area);
area_info info;
status_t status = get_area_info(id, &info);
if (status < B_OK)
goto err4;
return status;
// The area was successfully transferred to the new team when we got here
area->address_space = targetAddressSpace;
area_id clonedArea = vm_clone_area(target, info.name, _address,
addressSpec, info.protection, REGION_NO_PRIVATE_MAP, id);
if (clonedArea < B_OK)
return clonedArea;
// TODO: take area lock/wiring into account!
release_sem_etc(targetAddressSpace->sem, WRITE_COUNT, 0);
vm_unreserve_address_range(sourceAddressSpace->id, reservedAddress,
area->size);
vm_put_address_space(sourceAddressSpace);
// we keep the reference of the target address space for the
// area, so we only have to put the one from the source
vm_put_area(area);
return B_OK;
err4:
release_sem_etc(targetAddressSpace->sem, WRITE_COUNT, 0);
err3:
// insert the area again into the source address space
acquire_sem_etc(sourceAddressSpace->sem, WRITE_COUNT, 0, 0);
// check to see if this address space has entered DELETE state
if (sourceAddressSpace->state == VM_ASPACE_STATE_DELETION
|| 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 *cache = vm_area_get_locked_cache(area);
atomic_add(&area->no_cache_change, 1);
vm_area_put_locked_cache(cache);
vm_cache_remove_area(cache, area);
vm_cache_release_ref(cache);
free(area->name);
free(area);
area = NULL;
status = vm_delete_area(info.team, id);
if (status < B_OK) {
vm_delete_area(target, clonedArea);
return status;
}
release_sem_etc(sourceAddressSpace->sem, WRITE_COUNT, 0);
err2:
vm_put_address_space(targetAddressSpace);
err1:
if (area != NULL)
vm_put_area(area);
return status;
#endif
return clonedArea;
}
@@ -5272,7 +5185,7 @@ _user_resize_area(area_id area, size_t newSize)
}
status_t
area_id
_user_transfer_area(area_id area, void **userAddress, uint32 addressSpec, team_id target)
{
// filter out some unavailable values (for userland)
@@ -5287,14 +5200,14 @@ _user_transfer_area(area_id area, void **userAddress, uint32 addressSpec, team_i
|| user_memcpy(&address, userAddress, sizeof(address)) < B_OK)
return B_BAD_ADDRESS;
status_t status = transfer_area(area, &address, addressSpec, target);
if (status < B_OK)
return status;
area_id newArea = transfer_area(area, &address, addressSpec, target);
if (newArea < B_OK)
return newArea;
if (user_memcpy(userAddress, &address, sizeof(address)) < B_OK)
return B_BAD_ADDRESS;
return status;
return newArea;
}