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Revert "Kernel: Make DoubleBuffer use a KBuffer instead of kmalloc()ing"

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This reverts commit 1cca5142af.

This appears to be causing intermittent triple-faults and I don't know
why yet, so I'll just revert it to keep the tree in decent shape.
This commit is contained in:
Andreas Kling 2019-10-18 15:58:06 +02:00
parent 1cca5142af
commit ec65b8db2e
5 changed files with 34 additions and 53 deletions
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45
Kernel/DoubleBuffer.cpp
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@ -1,32 +1,20 @@
#include <Kernel/DoubleBuffer.h>
inline void DoubleBuffer::compute_lockfree_metadata()
inline void DoubleBuffer::compute_emptiness()
{
InterruptDisabler disabler;
m_empty = m_read_buffer_index >= m_read_buffer->size && m_write_buffer->size == 0;
m_space_for_writing = m_capacity - m_write_buffer->size;
}
DoubleBuffer::DoubleBuffer(size_t capacity)
: m_write_buffer(&m_buffer1)
, m_read_buffer(&m_buffer2)
, m_storage(KBuffer::create_with_size(capacity * 2))
, m_capacity(capacity)
{
m_buffer1.data = m_storage.data();
m_buffer1.size = 0;
m_buffer2.data = m_storage.data() + capacity;
m_buffer2.size = 0;
m_space_for_writing = capacity;
m_empty = m_read_buffer_index >= m_read_buffer->size() && m_write_buffer->is_empty();
}
void DoubleBuffer::flip()
{
ASSERT(m_read_buffer_index == m_read_buffer->size);
ASSERT(m_read_buffer_index == m_read_buffer->size());
swap(m_read_buffer, m_write_buffer);
m_write_buffer->size = 0;
if (m_write_buffer->capacity() < 32)
m_write_buffer->clear_with_capacity();
else
m_write_buffer->clear();
m_read_buffer_index = 0;
compute_lockfree_metadata();
compute_emptiness();
}
ssize_t DoubleBuffer::write(const u8* data, ssize_t size)
@ -34,11 +22,8 @@ ssize_t DoubleBuffer::write(const u8* data, ssize_t size)
if (!size)
return 0;
LOCKER(m_lock);
ASSERT(size <= (ssize_t)space_for_writing());
u8* write_ptr = m_write_buffer->data + m_write_buffer->size;
m_write_buffer->size += size;
compute_lockfree_metadata();
memcpy(write_ptr, data, size);
m_write_buffer->append(data, size);
compute_emptiness();
return size;
}
@ -47,13 +32,13 @@ ssize_t DoubleBuffer::read(u8* data, ssize_t size)
if (!size)
return 0;
LOCKER(m_lock);
if (m_read_buffer_index >= m_read_buffer->size && m_write_buffer->size != 0)
if (m_read_buffer_index >= m_read_buffer->size() && !m_write_buffer->is_empty())
flip();
if (m_read_buffer_index >= m_read_buffer->size)
if (m_read_buffer_index >= m_read_buffer->size())
return 0;
ssize_t nread = min((ssize_t)m_read_buffer->size - (ssize_t)m_read_buffer_index, size);
memcpy(data, m_read_buffer->data + m_read_buffer_index, nread);
ssize_t nread = min((ssize_t)m_read_buffer->size() - m_read_buffer_index, size);
memcpy(data, m_read_buffer->data() + m_read_buffer_index, nread);
m_read_buffer_index += nread;
compute_lockfree_metadata();
compute_emptiness();
return nread;
}