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8131c0de8c
We want to move this out of the AHCI subsystem into the VM system, since other parts of the kernel may need to perform scatter-gather IO. We rename the current VM::ScatterGatherList impl that's used in the virtio subsystem to VM::ScatterGatherRefList, since its distinguishing feature from the AHCI scatter-gather list is that it doesn't own its buffers.
59 lines
2.2 KiB
C++
59 lines
2.2 KiB
C++
/*
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* Copyright (c) 2021, the SerenityOS developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/VM/ScatterGatherList.h>
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namespace Kernel {
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NonnullRefPtr<ScatterGatherList> ScatterGatherList::create(AsyncBlockDeviceRequest& request, NonnullRefPtrVector<PhysicalPage> allocated_pages, size_t device_block_size)
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{
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return adopt_ref(*new ScatterGatherList(request, allocated_pages, device_block_size));
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}
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ScatterGatherList::ScatterGatherList(AsyncBlockDeviceRequest& request, NonnullRefPtrVector<PhysicalPage> allocated_pages, size_t device_block_size)
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: m_vm_object(AnonymousVMObject::create_with_physical_pages(allocated_pages))
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{
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m_dma_region = MM.allocate_kernel_region_with_vmobject(m_vm_object, page_round_up((request.block_count() * device_block_size)), "AHCI Scattered DMA", Region::Access::Read | Region::Access::Write, Region::Cacheable::Yes);
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}
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ScatterGatherRefList ScatterGatherRefList::create_from_buffer(const u8* buffer, size_t size)
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{
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VERIFY(buffer && size);
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ScatterGatherRefList new_list;
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auto* region = MM.find_region_from_vaddr(VirtualAddress(buffer));
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VERIFY(region);
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while (size > 0) {
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size_t offset_in_page = (VirtualAddress(buffer) - region->vaddr()).get() % PAGE_SIZE;
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size_t size_in_page = min(PAGE_SIZE - offset_in_page, size);
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VERIFY(offset_in_page + size_in_page - 1 <= PAGE_SIZE);
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new_list.add_entry(region->physical_page(region->page_index_from_address(VirtualAddress(buffer)))->paddr().get(), offset_in_page, size_in_page);
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size -= size_in_page;
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buffer += size_in_page;
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}
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return new_list;
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}
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ScatterGatherRefList ScatterGatherRefList::create_from_physical(PhysicalAddress paddr, size_t size)
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{
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VERIFY(!paddr.is_null() && size);
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ScatterGatherRefList new_list;
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new_list.add_entry(paddr.page_base().get(), paddr.offset_in_page(), size);
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return new_list;
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}
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void ScatterGatherRefList::add_entry(FlatPtr addr, size_t offset, size_t size)
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{
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m_entries.append({ addr, offset, size });
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}
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void ScatterGatherRefList::for_each_entry(Function<void(const FlatPtr, const size_t)> callback) const
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{
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for (auto& entry : m_entries)
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callback(entry.page_base + entry.offset, entry.length);
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}
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}
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