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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
5 changed files with 45 additions and 38 deletions
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34
Kernel/Memory/Region.cpp
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@ -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