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Kernel: Make Region::try_create_user_accessible() OOM-safe

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Previously we would simply assume that Region allocation always
succeeded. There is still one such assumption when splitting user
regions inside a Space. That will be dealt with in a separate commit.
This commit is contained in:
Andreas Kling 2021-07-11 18:07:12 +02:00
parent 241bbce264
commit cac557eee0
3 changed files with 33 additions and 14 deletions
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24
Kernel/VM/Space.cpp
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@ -145,8 +145,11 @@ Optional<Range> Space::allocate_range(VirtualAddress vaddr, size_t size, size_t
Region& Space::allocate_split_region(const Region& source_region, const Range& range, size_t offset_in_vmobject)
{
auto& region = add_region(Region::create_user_accessible(
m_process, range, source_region.vmobject(), offset_in_vmobject, KString::try_create(source_region.name()), source_region.access(), source_region.is_cacheable() ? Region::Cacheable::Yes : Region::Cacheable::No, source_region.is_shared()));
auto new_region = Region::try_create_user_accessible(
m_process, range, source_region.vmobject(), offset_in_vmobject, KString::try_create(source_region.name()), source_region.access(), source_region.is_cacheable() ? Region::Cacheable::Yes : Region::Cacheable::No, source_region.is_shared());
// FIXME: Handle !new_region (by propagating ENOMEM)
VERIFY(new_region);
auto& region = add_region(new_region.release_nonnull());
region.set_syscall_region(source_region.is_syscall_region());
region.set_mmap(source_region.is_mmap());
region.set_stack(source_region.is_stack());
@ -164,10 +167,12 @@ KResultOr<Region*> Space::allocate_region(Range const& range, StringView name, i
auto vmobject = AnonymousVMObject::try_create_with_size(range.size(), strategy);
if (!vmobject)
return ENOMEM;
auto region = Region::create_user_accessible(m_process, range, vmobject.release_nonnull(), 0, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, false);
auto region = Region::try_create_user_accessible(m_process, range, vmobject.release_nonnull(), 0, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, false);
if (!region)
return ENOMEM;
if (!region->map(page_directory()))
return ENOMEM;
return &add_region(move(region));
return &add_region(region.release_nonnull());
}
KResultOr<Region*> Space::allocate_region_with_vmobject(Range const& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, StringView name, int prot, bool shared)
@ -187,12 +192,17 @@ KResultOr<Region*> Space::allocate_region_with_vmobject(Range const& range, Nonn
return EINVAL;
}
offset_in_vmobject &= PAGE_MASK;
auto& region = add_region(Region::create_user_accessible(m_process, range, move(vmobject), offset_in_vmobject, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, shared));
if (!region.map(page_directory())) {
auto region = Region::try_create_user_accessible(m_process, range, move(vmobject), offset_in_vmobject, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, shared);
if (!region) {
dbgln("allocate_region_with_vmobject: Unable to allocate Region");
return nullptr;
}
auto& region_ref = add_region(region.release_nonnull());
if (!region_ref.map(page_directory())) {
// FIXME: What is an appropriate error code here, really?
return ENOMEM;
}
return &region;
return &region_ref;
}
bool Space::deallocate_region(Region& region)