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2c72d495a3
I believe this to be safe, as the main thing that LockRefPtr provides over RefPtr is safe copying from a shared LockRefPtr instance. I've inspected the uses of RefPtr<PhysicalPage> and it seems they're all guarded by external locking. Some of it is less obvious, but this is an area where we're making continuous headway.
64 lines
2.4 KiB
C++
64 lines
2.4 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/FileSystem/Inode.h>
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#include <Kernel/Locking/Spinlock.h>
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#include <Kernel/Memory/SharedInodeVMObject.h>
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namespace Kernel::Memory {
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ErrorOr<NonnullLockRefPtr<SharedInodeVMObject>> SharedInodeVMObject::try_create_with_inode(Inode& inode)
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{
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size_t size = inode.size();
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if (auto shared_vmobject = inode.shared_vmobject())
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return shared_vmobject.release_nonnull();
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auto new_physical_pages = TRY(VMObject::try_create_physical_pages(size));
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auto dirty_pages = TRY(Bitmap::try_create(new_physical_pages.size(), false));
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auto vmobject = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) SharedInodeVMObject(inode, move(new_physical_pages), move(dirty_pages))));
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TRY(vmobject->inode().set_shared_vmobject(*vmobject));
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return vmobject;
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}
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ErrorOr<NonnullLockRefPtr<VMObject>> SharedInodeVMObject::try_clone()
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{
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auto new_physical_pages = TRY(this->try_clone_physical_pages());
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auto dirty_pages = TRY(Bitmap::try_create(new_physical_pages.size(), false));
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return adopt_nonnull_lock_ref_or_enomem<VMObject>(new (nothrow) SharedInodeVMObject(*this, move(new_physical_pages), move(dirty_pages)));
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}
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SharedInodeVMObject::SharedInodeVMObject(Inode& inode, FixedArray<RefPtr<PhysicalPage>>&& new_physical_pages, Bitmap dirty_pages)
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: InodeVMObject(inode, move(new_physical_pages), move(dirty_pages))
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{
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}
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SharedInodeVMObject::SharedInodeVMObject(SharedInodeVMObject const& other, FixedArray<RefPtr<PhysicalPage>>&& new_physical_pages, Bitmap dirty_pages)
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: InodeVMObject(other, move(new_physical_pages), move(dirty_pages))
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{
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}
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ErrorOr<void> SharedInodeVMObject::sync(off_t offset_in_pages, size_t pages)
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{
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SpinlockLocker locker(m_lock);
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size_t highest_page_to_flush = min(page_count(), offset_in_pages + pages);
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for (size_t page_index = offset_in_pages; page_index < highest_page_to_flush; ++page_index) {
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auto& physical_page = m_physical_pages[page_index];
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if (!physical_page)
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continue;
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u8 page_buffer[PAGE_SIZE];
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MM.copy_physical_page(*physical_page, page_buffer);
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MutexLocker locker(m_inode->m_inode_lock);
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TRY(m_inode->write_bytes(page_index * PAGE_SIZE, PAGE_SIZE, UserOrKernelBuffer::for_kernel_buffer(page_buffer), nullptr));
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}
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return {};
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}
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}
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