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

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

View file

@ -1,38 +1,34 @@
#pragma once
#include <AK/Types.h>
#include <Kernel/KBuffer.h>
#include <AK/Vector.h>
#include <Kernel/Lock.h>
class DoubleBuffer {
public:
explicit DoubleBuffer(size_t capacity = 65536);
DoubleBuffer()
: m_write_buffer(&m_buffer1)
, m_read_buffer(&m_buffer2)
{
}
ssize_t write(const u8*, ssize_t);
ssize_t read(u8*, ssize_t);
bool is_empty() const { return m_empty; }
size_t space_for_writing() const { return m_space_for_writing; }
// FIXME: Isn't this racy? What if we get interrupted between getting the buffer pointer and dereferencing it?
ssize_t bytes_in_write_buffer() const { return (ssize_t)m_write_buffer->size(); }
private:
void flip();
void compute_lockfree_metadata();
void compute_emptiness();
struct InnerBuffer {
u8* data { nullptr };
size_t size;
};
InnerBuffer* m_write_buffer { nullptr };
InnerBuffer* m_read_buffer { nullptr };
InnerBuffer m_buffer1;
InnerBuffer m_buffer2;
KBuffer m_storage;
size_t m_capacity { 0 };
size_t m_read_buffer_index { 0 };
size_t m_space_for_writing { 0 };
Vector<u8>* m_write_buffer { nullptr };
Vector<u8>* m_read_buffer { nullptr };
Vector<u8> m_buffer1;
Vector<u8> m_buffer2;
ssize_t m_read_buffer_index { 0 };
bool m_empty { true };
mutable Lock m_lock { "DoubleBuffer" };
Lock m_lock { "DoubleBuffer" };
};