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Kernel: Make Kernel::VMObject allocation functions return KResultOr

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This makes for nicer handling of errors compared to checking whether a
RefPtr is null. Additionally, this will give way to return different
types of errors in the future.
This commit is contained in:
sin-ack 2021-08-15 09:07:59 +00:00 • committed by Andreas Kling
parent 61c0e3ca92
commit 4bfd6e41b9
26 changed files with 194 additions and 122 deletions
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57
Kernel/Memory/AnonymousVMObject.cpp
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@ -13,7 +13,7 @@
namespace Kernel::Memory {
RefPtr<VMObject> AnonymousVMObject::try_clone()
KResultOr<NonnullRefPtr<VMObject>> AnonymousVMObject::try_clone()
{
// We need to acquire our lock so we copy a sane state
ScopedSpinLock lock(m_lock);
@ -21,9 +21,11 @@ RefPtr<VMObject> AnonymousVMObject::try_clone()
if (is_purgeable() && is_volatile()) {
// If this object is purgeable+volatile, create a new zero-filled purgeable+volatile
// object, effectively "pre-purging" it in the child process.
auto clone = try_create_purgeable_with_size(size(), AllocationStrategy::None);
if (!clone)
return {};
auto maybe_clone = try_create_purgeable_with_size(size(), AllocationStrategy::None);
if (maybe_clone.is_error())
return maybe_clone.error();
auto clone = maybe_clone.release_value();
clone->m_volatile = true;
return clone;
}
@ -38,7 +40,7 @@ RefPtr<VMObject> AnonymousVMObject::try_clone()
auto committed_pages = MM.commit_user_physical_pages(new_cow_pages_needed);
if (!committed_pages.has_value())
return {};
return ENOMEM;
// Create or replace the committed cow pages. When cloning a previously
// cloned vmobject, we want to essentially "fork", leaving us and the
@ -49,11 +51,12 @@ RefPtr<VMObject> AnonymousVMObject::try_clone()
auto new_shared_committed_cow_pages = try_create<SharedCommittedCowPages>(committed_pages.release_value());
if (!new_shared_committed_cow_pages)
return {};
return ENOMEM;
auto clone = adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(*this, *new_shared_committed_cow_pages));
if (!clone)
return {};
auto maybe_clone = adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(*this, new_shared_committed_cow_pages.release_nonnull()));
if (!maybe_clone)
return ENOMEM;
auto clone = maybe_clone.release_nonnull();
m_shared_committed_cow_pages = move(new_shared_committed_cow_pages);
@ -76,52 +79,58 @@ RefPtr<VMObject> AnonymousVMObject::try_clone()
return clone;
}
RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_with_size(size_t size, AllocationStrategy strategy)
KResultOr<NonnullRefPtr<AnonymousVMObject>> AnonymousVMObject::try_create_with_size(size_t size, AllocationStrategy strategy)
{
Optional<CommittedPhysicalPageSet> committed_pages;
if (strategy == AllocationStrategy::Reserve || strategy == AllocationStrategy::AllocateNow) {
committed_pages = MM.commit_user_physical_pages(ceil_div(size, static_cast<size_t>(PAGE_SIZE)));
if (!committed_pages.has_value())
return {};
return ENOMEM;
}
return adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(size, strategy, move(committed_pages)));
return adopt_nonnull_ref_or_enomem(new (nothrow) AnonymousVMObject(size, strategy, move(committed_pages)));
}
RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_physically_contiguous_with_size(size_t size)
KResultOr<NonnullRefPtr<AnonymousVMObject>> AnonymousVMObject::try_create_physically_contiguous_with_size(size_t size)
{
auto contiguous_physical_pages = MM.allocate_contiguous_supervisor_physical_pages(size);
if (contiguous_physical_pages.is_empty())
return {};
return adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(contiguous_physical_pages.span()));
return ENOMEM;
return adopt_nonnull_ref_or_enomem(new (nothrow) AnonymousVMObject(contiguous_physical_pages.span()));
}
RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_purgeable_with_size(size_t size, AllocationStrategy strategy)
KResultOr<NonnullRefPtr<AnonymousVMObject>> AnonymousVMObject::try_create_purgeable_with_size(size_t size, AllocationStrategy strategy)
{
Optional<CommittedPhysicalPageSet> committed_pages;
if (strategy == AllocationStrategy::Reserve || strategy == AllocationStrategy::AllocateNow) {
committed_pages = MM.commit_user_physical_pages(ceil_div(size, static_cast<size_t>(PAGE_SIZE)));
if (!committed_pages.has_value())
return {};
return ENOMEM;
}
auto vmobject = adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(size, strategy, move(committed_pages)));
if (!vmobject)
return {};
return ENOMEM;
vmobject->m_purgeable = true;
return vmobject;
return vmobject.release_nonnull();
}
RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_with_physical_pages(Span<NonnullRefPtr<PhysicalPage>> physical_pages)
KResultOr<NonnullRefPtr<AnonymousVMObject>> AnonymousVMObject::try_create_with_physical_pages(Span<NonnullRefPtr<PhysicalPage>> physical_pages)
{
return adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(physical_pages));
return adopt_nonnull_ref_or_enomem(new (nothrow) AnonymousVMObject(physical_pages));
}
RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_for_physical_range(PhysicalAddress paddr, size_t size)
KResultOr<NonnullRefPtr<AnonymousVMObject>> AnonymousVMObject::try_create_for_physical_range(PhysicalAddress paddr, size_t size)
{
if (paddr.offset(size) < paddr) {
dbgln("Shenanigans! try_create_for_physical_range({}, {}) would wrap around", paddr, size);
return nullptr;
// Since we can't wrap around yet, let's pretend to OOM.
return ENOMEM;
}
return adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(paddr, size));
return adopt_nonnull_ref_or_enomem(new (nothrow) AnonymousVMObject(paddr, size));
}
AnonymousVMObject::AnonymousVMObject(size_t size, AllocationStrategy strategy, Optional<CommittedPhysicalPageSet> committed_pages)