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79fa9765ca
We now use AK::Error and AK::ErrorOr<T> in both kernel and userspace! This was a slightly tedious refactoring that took a long time, so it's not unlikely that some bugs crept in. Nevertheless, it does pass basic functionality testing, and it's just real nice to finally see the same pattern in all contexts. :^)
64 lines
2.5 KiB
C++
64 lines
2.5 KiB
C++
/*
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* Copyright (c) 2021, Sahan Fernando <sahan.h.fernando@gmail.com>.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <Kernel/Memory/MemoryManager.h>
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#include <Kernel/Memory/RingBuffer.h>
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#include <Kernel/UserOrKernelBuffer.h>
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namespace Kernel::Memory {
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RingBuffer::RingBuffer(String region_name, size_t capacity)
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: m_region(MM.allocate_contiguous_kernel_region(page_round_up(capacity), move(region_name), Region::Access::Read | Region::Access::Write).release_value())
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, m_capacity_in_bytes(capacity)
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{
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}
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bool RingBuffer::copy_data_in(const UserOrKernelBuffer& buffer, size_t offset, size_t length, PhysicalAddress& start_of_copied_data, size_t& bytes_copied)
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{
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size_t start_of_free_area = (m_start_of_used + m_num_used_bytes) % m_capacity_in_bytes;
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bytes_copied = min(m_capacity_in_bytes - m_num_used_bytes, min(m_capacity_in_bytes - start_of_free_area, length));
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if (bytes_copied == 0)
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return false;
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if (auto result = buffer.read(m_region->vaddr().offset(start_of_free_area).as_ptr(), offset, bytes_copied); result.is_error())
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return false;
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m_num_used_bytes += bytes_copied;
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start_of_copied_data = m_region->physical_page(start_of_free_area / PAGE_SIZE)->paddr().offset(start_of_free_area % PAGE_SIZE);
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return true;
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}
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ErrorOr<size_t> RingBuffer::copy_data_out(size_t size, UserOrKernelBuffer& buffer) const
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{
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auto start = m_start_of_used % m_capacity_in_bytes;
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auto num_bytes = min(min(m_num_used_bytes, size), m_capacity_in_bytes - start);
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TRY(buffer.write(m_region->vaddr().offset(start).as_ptr(), num_bytes));
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return num_bytes;
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}
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ErrorOr<PhysicalAddress> RingBuffer::reserve_space(size_t size)
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{
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if (m_capacity_in_bytes < m_num_used_bytes + size)
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return ENOSPC;
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size_t start_of_free_area = (m_start_of_used + m_num_used_bytes) % m_capacity_in_bytes;
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m_num_used_bytes += size;
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PhysicalAddress start_of_reserved_space = m_region->physical_page(start_of_free_area / PAGE_SIZE)->paddr().offset(start_of_free_area % PAGE_SIZE);
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return start_of_reserved_space;
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}
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void RingBuffer::reclaim_space(PhysicalAddress chunk_start, size_t chunk_size)
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{
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VERIFY(start_of_used() == chunk_start);
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VERIFY(m_num_used_bytes >= chunk_size);
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m_num_used_bytes -= chunk_size;
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m_start_of_used += chunk_size;
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}
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PhysicalAddress RingBuffer::start_of_used() const
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{
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size_t start = m_start_of_used % m_capacity_in_bytes;
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return m_region->physical_page(start / PAGE_SIZE)->paddr().offset(start % PAGE_SIZE);
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}
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}
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