ladybird/Kernel/VM/ScatterGatherList.cpp
Brian Gianforcaro 1682f0b760 Everything: Move to SPDX license identifiers in all files.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.

See: https://spdx.dev/resources/use/#identifiers

This was done with the `ambr` search and replace tool.

 ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 11:22:27 +02:00

47 lines
1.5 KiB
C++

/*
* Copyright (c) 2021, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <Kernel/VM/ScatterGatherList.h>
namespace Kernel {
ScatterGatherList ScatterGatherList::create_from_buffer(const u8* buffer, size_t size)
{
VERIFY(buffer && size);
ScatterGatherList new_list;
auto* region = MM.find_region_from_vaddr(VirtualAddress(buffer));
VERIFY(region);
while (size > 0) {
size_t offset_in_page = (VirtualAddress(buffer) - region->vaddr()).get() % PAGE_SIZE;
size_t size_in_page = min(PAGE_SIZE - offset_in_page, size);
VERIFY(offset_in_page + size_in_page - 1 <= PAGE_SIZE);
new_list.add_entry(region->physical_page(region->page_index_from_address(VirtualAddress(buffer)))->paddr().get(), offset_in_page, size_in_page);
size -= size_in_page;
buffer += size_in_page;
}
return new_list;
}
ScatterGatherList ScatterGatherList::create_from_physical(PhysicalAddress paddr, size_t size)
{
VERIFY(!paddr.is_null() && size);
ScatterGatherList 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)
{
m_entries.append({ addr, offset, size });
}
void ScatterGatherList::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);
}
}