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https://github.com/SerenityOS/serenity
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75564b4a5f
This expands the reach of error propagation greatly throughout the kernel. Sadly, it also exposes the fact that we're allocating (and doing other fallible things) in constructors all over the place. This patch doesn't attempt to address that of course. That's work for our future selves.
67 lines
2.5 KiB
C++
67 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 (buffer.read(m_region->vaddr().offset(start_of_free_area).as_ptr(), offset, bytes_copied)) {
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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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return false;
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}
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KResultOr<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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if (!buffer.write(m_region->vaddr().offset(start).as_ptr(), num_bytes))
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return EIO;
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return num_bytes;
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}
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KResultOr<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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