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Kernel: Move AHCIPort::ScatterList to VM::ScatterGatherList

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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.
This commit is contained in:
Sahan Fernando 2021-04-24 11:30:27 +10:00 • committed by Andreas Kling
parent b63b15eeb5
commit 8131c0de8c
11 changed files with 53 additions and 46 deletions
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2
Kernel/VM/MemoryManager.h
View file

@ -104,7 +104,7 @@ class MemoryManager {
friend class PhysicalRegion;
friend class AnonymousVMObject;
friend class Region;
friend class ScatterGatherList;
friend class ScatterGatherRefList;
friend class VMObject;
public:

23
Kernel/VM/ScatterGatherList.cpp
View file

@ -8,10 +8,21 @@
namespace Kernel {
ScatterGatherList ScatterGatherList::create_from_buffer(const u8* buffer, size_t size)
NonnullRefPtr<ScatterGatherList> ScatterGatherList::create(AsyncBlockDeviceRequest& request, NonnullRefPtrVector<PhysicalPage> allocated_pages, size_t device_block_size)
{
return adopt_ref(*new ScatterGatherList(request, allocated_pages, device_block_size));
}
ScatterGatherList::ScatterGatherList(AsyncBlockDeviceRequest& request, NonnullRefPtrVector<PhysicalPage> allocated_pages, size_t device_block_size)
: m_vm_object(AnonymousVMObject::create_with_physical_pages(allocated_pages))
{
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);
}
ScatterGatherRefList ScatterGatherRefList::create_from_buffer(const u8* buffer, size_t size)
{
VERIFY(buffer && size);
ScatterGatherList new_list;
ScatterGatherRefList new_list;
auto* region = MM.find_region_from_vaddr(VirtualAddress(buffer));
VERIFY(region);
while (size > 0) {
@ -25,20 +36,20 @@ ScatterGatherList ScatterGatherList::create_from_buffer(const u8* buffer, size_t
return new_list;
}
ScatterGatherList ScatterGatherList::create_from_physical(PhysicalAddress paddr, size_t size)
ScatterGatherRefList ScatterGatherRefList::create_from_physical(PhysicalAddress paddr, size_t size)
{
VERIFY(!paddr.is_null() && size);
ScatterGatherList new_list;
ScatterGatherRefList new_list;
new_list.add_entry(paddr.page_base().get(), paddr.offset_in_page(), size);
return new_list;
}
void ScatterGatherList::add_entry(FlatPtr addr, size_t offset, size_t size)
void ScatterGatherRefList::add_entry(FlatPtr addr, size_t offset, size_t size)
{
m_entries.append({ addr, offset, size });
}
void ScatterGatherList::for_each_entry(Function<void(const FlatPtr, const size_t)> callback) const
void ScatterGatherRefList::for_each_entry(Function<void(const FlatPtr, const size_t)> callback) const
{
for (auto& entry : m_entries)
callback(entry.page_base + entry.offset, entry.length);

29
Kernel/VM/ScatterGatherList.h
View file

@ -7,21 +7,40 @@
#pragma once
#include <AK/Vector.h>
#include <Kernel/Devices/BlockDevice.h>
#include <Kernel/PhysicalAddress.h>
#include <Kernel/VM/AnonymousVMObject.h>
#include <Kernel/VM/MemoryManager.h>
namespace Kernel {
class ScatterGatherList {
struct ScatterGatherEntry {
/// A Scatter-Gather List type that owns its buffers
class ScatterGatherList : public RefCounted<ScatterGatherList> {
public:
static NonnullRefPtr<ScatterGatherList> create(AsyncBlockDeviceRequest&, NonnullRefPtrVector<PhysicalPage> allocated_pages, size_t device_block_size);
const VMObject& vmobject() const { return m_vm_object; }
VirtualAddress dma_region() const { return m_dma_region->vaddr(); }
size_t scatters_count() const { return m_vm_object->physical_pages().size(); }
private:
ScatterGatherList(AsyncBlockDeviceRequest&, NonnullRefPtrVector<PhysicalPage> allocated_pages, size_t device_block_size);
NonnullRefPtr<AnonymousVMObject> m_vm_object;
OwnPtr<Region> m_dma_region;
};
/// A Scatter-Gather List type that doesn't own its buffers
class ScatterGatherRefList {
struct ScatterGatherRef {
FlatPtr page_base;
size_t offset;
size_t length;
};
public:
static ScatterGatherList create_from_buffer(const u8* buffer, size_t);
static ScatterGatherList create_from_physical(PhysicalAddress, size_t);
static ScatterGatherRefList create_from_buffer(const u8* buffer, size_t);
static ScatterGatherRefList create_from_physical(PhysicalAddress, size_t);
void add_entry(FlatPtr, size_t offset, size_t size);
[[nodiscard]] size_t length() const { return m_entries.size(); }
@ -29,7 +48,7 @@ public:
void for_each_entry(Function<void(const FlatPtr, const size_t)> callback) const;
private:
Vector<ScatterGatherEntry> m_entries;
Vector<ScatterGatherRef> m_entries;
};
}