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Kernel: Make Memory::Region allocation functions return KResultOr

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This makes for some nicer handling of errors compared to checking an
OwnPtr for null state.
This commit is contained in:
sin-ack 2021-08-15 10:11:05 +00:00 • committed by Andreas Kling
parent 4bfd6e41b9
commit 0a18425cbb
Notes: sideshowbarker 2024-07-18 05:39:28 +09:00
5 changed files with 45 additions and 38 deletions
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26
Kernel/Memory/AddressSpace.cpp
View file

@ -149,11 +149,11 @@ Optional<VirtualRange> AddressSpace::allocate_range(VirtualAddress vaddr, size_t
KResultOr<Region*> AddressSpace::try_allocate_split_region(Region const& source_region, VirtualRange const& range, size_t offset_in_vmobject)
{
auto new_region = Region::try_create_user_accessible(
auto maybe_new_region = Region::try_create_user_accessible(
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());
if (!new_region)
return ENOMEM;
auto* region = add_region(new_region.release_nonnull());
if (maybe_new_region.is_error())
return maybe_new_region.error();
auto* region = add_region(maybe_new_region.release_value());
if (!region)
return ENOMEM;
region->set_syscall_region(source_region.is_syscall_region());
@ -173,12 +173,14 @@ KResultOr<Region*> AddressSpace::allocate_region(VirtualRange const& range, Stri
auto maybe_vmobject = AnonymousVMObject::try_create_with_size(range.size(), strategy);
if (maybe_vmobject.is_error())
return maybe_vmobject.error();
auto region = Region::try_create_user_accessible(range, maybe_vmobject.release_value(), 0, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, false);
if (!region)
return ENOMEM;
auto maybe_region = Region::try_create_user_accessible(range, maybe_vmobject.release_value(), 0, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, false);
if (maybe_region.is_error())
return maybe_region.error();
auto region = maybe_region.release_value();
if (!region->map(page_directory()))
return ENOMEM;
auto* added_region = add_region(region.release_nonnull());
auto* added_region = add_region(move(region));
if (!added_region)
return ENOMEM;
return added_region;
@ -201,12 +203,12 @@ KResultOr<Region*> AddressSpace::allocate_region_with_vmobject(VirtualRange cons
return EINVAL;
}
offset_in_vmobject &= PAGE_MASK;
auto region = Region::try_create_user_accessible(range, move(vmobject), offset_in_vmobject, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, shared);
if (!region) {
auto maybe_region = Region::try_create_user_accessible(range, move(vmobject), offset_in_vmobject, KString::try_create(name), prot_to_region_access_flags(prot), Region::Cacheable::Yes, shared);
if (maybe_region.is_error()) {
dbgln("allocate_region_with_vmobject: Unable to allocate Region");
return ENOMEM;
return maybe_region.error();
}
auto* added_region = add_region(region.release_nonnull());
auto* added_region = add_region(maybe_region.release_value());
if (!added_region)
return ENOMEM;
if (!added_region->map(page_directory()))

9
Kernel/Memory/MemoryManager.cpp
View file

@ -743,9 +743,12 @@ OwnPtr<Region> MemoryManager::allocate_kernel_region(PhysicalAddress paddr, size
OwnPtr<Region> MemoryManager::allocate_kernel_region_with_vmobject(VirtualRange const& range, VMObject& vmobject, StringView name, Region::Access access, Region::Cacheable cacheable)
{
auto region = Region::try_create_kernel_only(range, vmobject, 0, KString::try_create(name), access, cacheable);
if (region)
region->map(kernel_page_directory());
auto maybe_region = Region::try_create_kernel_only(range, vmobject, 0, KString::try_create(name), access, cacheable);
if (maybe_region.is_error())
return {};
auto region = maybe_region.release_value();
region->map(kernel_page_directory());
return region;
}

34
Kernel/Memory/Region.cpp
View file

@ -50,7 +50,7 @@ Region::~Region()
}
}
OwnPtr<Region> Region::clone()
KResultOr<NonnullOwnPtr<Region>> Region::try_clone()
{
VERIFY(Process::current());
@ -60,12 +60,14 @@ OwnPtr<Region> Region::clone()
VERIFY(vmobject().is_shared_inode());
// Create a new region backed by the same VMObject.
auto region = Region::try_create_user_accessible(
auto maybe_region = Region::try_create_user_accessible(
m_range, m_vmobject, m_offset_in_vmobject, m_name ? m_name->try_clone() : OwnPtr<KString> {}, access(), m_cacheable ? Cacheable::Yes : Cacheable::No, m_shared);
if (!region) {
if (maybe_region.is_error()) {
dbgln("Region::clone: Unable to allocate new Region");
return nullptr;
return maybe_region.error();
}
auto region = maybe_region.release_value();
region->set_mmap(m_mmap);
region->set_shared(m_shared);
region->set_syscall_region(is_syscall_region());
@ -77,16 +79,19 @@ OwnPtr<Region> Region::clone()
auto maybe_vmobject_clone = vmobject().try_clone();
if (maybe_vmobject_clone.is_error())
return {};
return maybe_vmobject_clone.error();
auto vmobject_clone = maybe_vmobject_clone.release_value();
// Set up a COW region. The parent (this) region becomes COW as well!
remap();
auto clone_region = Region::try_create_user_accessible(
m_range, maybe_vmobject_clone.release_value(), m_offset_in_vmobject, m_name ? m_name->try_clone() : OwnPtr<KString> {}, access(), m_cacheable ? Cacheable::Yes : Cacheable::No, m_shared);
if (!clone_region) {
auto maybe_clone_region = Region::try_create_user_accessible(
m_range, vmobject_clone, m_offset_in_vmobject, m_name ? m_name->try_clone() : OwnPtr<KString> {}, access(), m_cacheable ? Cacheable::Yes : Cacheable::No, m_shared);
if (maybe_clone_region.is_error()) {
dbgln("Region::clone: Unable to allocate new Region for COW");
return nullptr;
return maybe_clone_region.error();
}
auto clone_region = maybe_clone_region.release_value();
if (m_stack) {
VERIFY(is_readable());
VERIFY(is_writable());
@ -143,17 +148,14 @@ size_t Region::amount_shared() const
return bytes;
}
OwnPtr<Region> Region::try_create_user_accessible(VirtualRange const& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable cacheable, bool shared)
KResultOr<NonnullOwnPtr<Region>> Region::try_create_user_accessible(VirtualRange const& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable cacheable, bool shared)
{
auto region = adopt_own_if_nonnull(new (nothrow) Region(range, move(vmobject), offset_in_vmobject, move(name), access, cacheable, shared));
if (!region)
return nullptr;
return region;
return adopt_nonnull_own_or_enomem(new (nothrow) Region(range, move(vmobject), offset_in_vmobject, move(name), access, cacheable, shared));
}
OwnPtr<Region> Region::try_create_kernel_only(VirtualRange const& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable cacheable)
KResultOr<NonnullOwnPtr<Region>> Region::try_create_kernel_only(VirtualRange const& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable cacheable)
{
return adopt_own_if_nonnull(new (nothrow) Region(range, move(vmobject), offset_in_vmobject, move(name), access, cacheable, false));
return adopt_nonnull_own_or_enomem(new (nothrow) Region(range, move(vmobject), offset_in_vmobject, move(name), access, cacheable, false));
}
bool Region::should_cow(size_t page_index) const

6
Kernel/Memory/Region.h
View file

@ -49,8 +49,8 @@ public:
Yes,
};
static OwnPtr<Region> try_create_user_accessible(VirtualRange const&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable, bool shared);
static OwnPtr<Region> try_create_kernel_only(VirtualRange const&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable = Cacheable::Yes);
static KResultOr<NonnullOwnPtr<Region>> try_create_user_accessible(VirtualRange const&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable, bool shared);
static KResultOr<NonnullOwnPtr<Region>> try_create_kernel_only(VirtualRange const&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable = Cacheable::Yes);
~Region();
@ -90,7 +90,7 @@ public:
PageFaultResponse handle_fault(PageFault const&);
OwnPtr<Region> clone();
KResultOr<NonnullOwnPtr<Region>> try_clone();
bool contains(VirtualAddress vaddr) const
{

8
Kernel/Syscalls/fork.cpp
View file

@ -96,14 +96,14 @@ KResultOr<FlatPtr> Process::sys$fork(RegisterState& regs)
ScopedSpinLock lock(address_space().get_lock());
for (auto& region : address_space().regions()) {
dbgln_if(FORK_DEBUG, "fork: cloning Region({}) '{}' @ {}", region, region->name(), region->vaddr());
auto region_clone = region->clone();
if (!region_clone) {
auto maybe_region_clone = region->try_clone();
if (maybe_region_clone.is_error()) {
dbgln("fork: Cannot clone region, insufficient memory");
// TODO: tear down new process?
return ENOMEM;
return maybe_region_clone.error();
}
auto* child_region = child->address_space().add_region(region_clone.release_nonnull());
auto* child_region = child->address_space().add_region(maybe_region_clone.release_value());
if (!child_region) {
dbgln("fork: Cannot add region, insufficient memory");
// TODO: tear down new process?