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Kernel: Implement an asynchronous device request stack

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This allows issuing asynchronous requests for devices and waiting
on the completion of the request. The requests can cascade into
multiple sub-requests.

Since IRQs may complete at any time, if the current process is no
longer the same that started the process, we need to swich the
paging context before accessing user buffers.

Change the PATA driver to use this model.
This commit is contained in:
Tom 2020-11-02 11:16:01 -07:00 • committed by Andreas Kling
parent 96081010dc
commit 2fd5ce1eb0
17 changed files with 804 additions and 246 deletions
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124
Kernel/Devices/PATADiskDevice.cpp
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@ -55,22 +55,10 @@ const char* PATADiskDevice::class_name() const
return "PATADiskDevice";
}
bool PATADiskDevice::read_blocks(unsigned index, u16 count, UserOrKernelBuffer& out)
void PATADiskDevice::start_request(AsyncBlockDeviceRequest& request)
{
if (!m_channel.m_bus_master_base.is_null() && m_channel.m_dma_enabled.resource())
return read_sectors_with_dma(index, count, out);
return read_sectors(index, count, out);
}
bool PATADiskDevice::write_blocks(unsigned index, u16 count, const UserOrKernelBuffer& data)
{
if (!m_channel.m_bus_master_base.is_null() && m_channel.m_dma_enabled.resource())
return write_sectors_with_dma(index, count, data);
for (unsigned i = 0; i < count; ++i) {
if (!write_sectors(index + i, 1, data.offset(i * 512)))
return false;
}
return true;
bool use_dma = !m_channel.m_bus_master_base.is_null() && m_channel.m_dma_enabled.resource();
m_channel.start_request(request, use_dma, is_slave());
}
void PATADiskDevice::set_drive_geometry(u16 cyls, u16 heads, u16 spt)
@ -100,8 +88,19 @@ KResultOr<size_t> PATADiskDevice::read(FileDescription&, size_t offset, UserOrKe
#endif
if (whole_blocks > 0) {
if (!read_blocks(index, whole_blocks, outbuf))
return -1;
auto read_request = make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Read, index, whole_blocks, outbuf, whole_blocks * block_size());
auto result = read_request->wait();
if (result.wait_result().was_interrupted())
return KResult(-EINTR);
switch (result.request_result()) {
case AsyncDeviceRequest::Failure:
case AsyncDeviceRequest::Cancelled:
return KResult(-EIO);
case AsyncDeviceRequest::MemoryFault:
return KResult(-EFAULT);
default:
break;
}
}
off_t pos = whole_blocks * block_size();
@ -109,8 +108,21 @@ KResultOr<size_t> PATADiskDevice::read(FileDescription&, size_t offset, UserOrKe
if (remaining > 0) {
auto data = ByteBuffer::create_uninitialized(block_size());
auto data_buffer = UserOrKernelBuffer::for_kernel_buffer(data.data());
if (!read_blocks(index + whole_blocks, 1, data_buffer))
auto read_request = make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Read, index + whole_blocks, 1, data_buffer, block_size());
auto result = read_request->wait();
if (result.wait_result().was_interrupted())
return KResult(-EINTR);
switch (result.request_result()) {
case AsyncDeviceRequest::Failure:
return pos;
case AsyncDeviceRequest::Cancelled:
return KResult(-EIO);
case AsyncDeviceRequest::MemoryFault:
// This should never happen, we're writing to a kernel buffer!
ASSERT_NOT_REACHED();
default:
break;
}
if (!outbuf.write(data.data(), pos, remaining))
return KResult(-EFAULT);
}
@ -143,8 +155,19 @@ KResultOr<size_t> PATADiskDevice::write(FileDescription&, size_t offset, const U
#endif
if (whole_blocks > 0) {
if (!write_blocks(index, whole_blocks, inbuf))
return -1;
auto write_request = make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Write, index, whole_blocks, inbuf, whole_blocks * block_size());
auto result = write_request->wait();
if (result.wait_result().was_interrupted())
return KResult(-EINTR);
switch (result.request_result()) {
case AsyncDeviceRequest::Failure:
case AsyncDeviceRequest::Cancelled:
return KResult(-EIO);
case AsyncDeviceRequest::MemoryFault:
return KResult(-EFAULT);
default:
break;
}
}
off_t pos = whole_blocks * block_size();
@ -155,12 +178,45 @@ KResultOr<size_t> PATADiskDevice::write(FileDescription&, size_t offset, const U
if (remaining > 0) {
auto data = ByteBuffer::create_zeroed(block_size());
auto data_buffer = UserOrKernelBuffer::for_kernel_buffer(data.data());
if (!read_blocks(index + whole_blocks, 1, data_buffer))
return pos;
{
auto read_request = make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Read, index + whole_blocks, 1, data_buffer, block_size());
auto result = read_request->wait();
if (result.wait_result().was_interrupted())
return KResult(-EINTR);
switch (result.request_result()) {
case AsyncDeviceRequest::Failure:
return pos;
case AsyncDeviceRequest::Cancelled:
return KResult(-EIO);
case AsyncDeviceRequest::MemoryFault:
// This should never happen, we're writing to a kernel buffer!
ASSERT_NOT_REACHED();
default:
break;
}
}
if (!inbuf.read(data.data(), pos, remaining))
return KResult(-EFAULT);
if (!write_blocks(index + whole_blocks, 1, data_buffer))
return pos;
{
auto write_request = make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Write, index + whole_blocks, 1, data_buffer, block_size());
auto result = write_request->wait();
if (result.wait_result().was_interrupted())
return KResult(-EINTR);
switch (result.request_result()) {
case AsyncDeviceRequest::Failure:
return pos;
case AsyncDeviceRequest::Cancelled:
return KResult(-EIO);
case AsyncDeviceRequest::MemoryFault:
// This should never happen, we're writing to a kernel buffer!
ASSERT_NOT_REACHED();
default:
break;
}
}
}
return pos + remaining;
@ -171,26 +227,6 @@ bool PATADiskDevice::can_write(const FileDescription&, size_t offset) const
return offset < (m_cylinders * m_heads * m_sectors_per_track * block_size());
}
bool PATADiskDevice::read_sectors_with_dma(u32 lba, u16 count, UserOrKernelBuffer& outbuf)
{
return m_channel.ata_read_sectors_with_dma(lba, count, outbuf, is_slave());
}
bool PATADiskDevice::read_sectors(u32 start_sector, u16 count, UserOrKernelBuffer& outbuf)
{
return m_channel.ata_read_sectors(start_sector, count, outbuf, is_slave());
}
bool PATADiskDevice::write_sectors_with_dma(u32 lba, u16 count, const UserOrKernelBuffer& inbuf)
{
return m_channel.ata_write_sectors_with_dma(lba, count, inbuf, is_slave());
}
bool PATADiskDevice::write_sectors(u32 start_sector, u16 count, const UserOrKernelBuffer& inbuf)
{
return m_channel.ata_write_sectors(start_sector, count, inbuf, is_slave());
}
bool PATADiskDevice::is_slave() const
{
return m_drive_type == DriveType::Slave;