Revert "Kernel: Implement an asynchronous device request stack"

This reverts commit 2fd5ce1eb06e5cbbb180cba64a567e99f0cd846c.

This broke booting without SMP. (PR was #3921)

17 files changed, 241 insertions, 799 deletions

diff --git a/Kernel/CMakeLists.txt b/Kernel/CMakeLists.txt
index 6112a857a9..e6c7997231 100644
--- a/Kernel/CMakeLists.txt
+++ b/Kernel/CMakeLists.txt
@@ -14,7 +14,6 @@ set(KERNEL_SOURCES
     CMOS.cpp
     CommandLine.cpp
     Console.cpp
-    Devices/AsyncDeviceRequest.cpp
     Devices/BXVGADevice.cpp
     Devices/BlockDevice.cpp
     Devices/CharacterDevice.cpp
diff --git a/Kernel/Devices/AsyncDeviceRequest.cpp b/Kernel/Devices/AsyncDeviceRequest.cpp
deleted file mode 100644
index a114584085..0000000000
--- a/Kernel/Devices/AsyncDeviceRequest.cpp
+++ /dev/null
@@ -1,175 +0,0 @@
-/*
- * Copyright (c) 2020, The SerenityOS developers.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include <Kernel/Devices/AsyncDeviceRequest.h>
-#include <Kernel/Devices/Device.h>
-
-namespace Kernel {
-
-AsyncDeviceRequest::AsyncDeviceRequest(Device& device)
-    : m_device(device)
-    , m_process(*Process::current())
-{
-}
-
-AsyncDeviceRequest::~AsyncDeviceRequest()
-{
-    {
-        ScopedSpinLock lock(m_lock);
-        ASSERT(is_completed_result(m_result));
-        ASSERT(m_sub_requests_pending.is_empty());
-    }
-
-    // We should not need any locking here anymore. The destructor should
-    // only be called until either wait() or cancel() (once implemented) returned.
-    // At that point no sub-request should be adding more requests and all
-    // sub-requests should be completed (either succeeded, failed, or cancelled).
-    // Which means there should be no more pending sub-requests and the
-    // entire AsyncDeviceRequest hirarchy should be immutable.
-    for (auto& sub_request : m_sub_requests_complete) {
-        ASSERT(is_completed_result(sub_request.m_result)); // Shouldn't need any locking anymore
-        ASSERT(sub_request.m_parent_request == this);
-        sub_request.m_parent_request = nullptr;
-    }
-}
-
-void AsyncDeviceRequest::request_finished()
-{
-    if (m_parent_request)
-        m_parent_request->sub_request_finished(*this);
-
-    // Trigger processing the next request
-    m_device.process_next_queued_request({}, *this);
-
-    // Wake anyone who may be waiting
-    m_queue.wake_all();
-}
-
-auto AsyncDeviceRequest::wait(timeval* timeout) -> RequestWaitResult
-{
-    ASSERT(!m_parent_request);
-    auto request_result = get_request_result();
-    if (is_completed_result(request_result))
-        return { request_result, Thread::BlockResult::NotBlocked };
-    auto wait_result = Thread::current()->wait_on(m_queue, name(), timeout);
-    return { get_request_result(), wait_result };
-}
-
-auto AsyncDeviceRequest::get_request_result() const -> RequestResult
-{
-    ScopedSpinLock lock(m_lock);
-    return m_result;
-}
-
-void AsyncDeviceRequest::add_sub_request(NonnullRefPtr<AsyncDeviceRequest> sub_request)
-{
-    // Sub-requests cannot be for the same device
-    ASSERT(&m_device != &sub_request->m_device);
-    ASSERT(sub_request->m_parent_request == nullptr);
-    sub_request->m_parent_request = this;
-
-    bool should_start;
-    {
-        ScopedSpinLock lock(m_lock);
-        ASSERT(!is_completed_result(m_result));
-        m_sub_requests_pending.append(sub_request);
-        should_start = (m_result == Started);
-    }
-    if (should_start)
-        sub_request->do_start();
-}
-
-void AsyncDeviceRequest::sub_request_finished(AsyncDeviceRequest& sub_request)
-{
-    bool all_completed;
-    {
-        ScopedSpinLock lock(m_lock);
-        ASSERT(m_result == Started);
-        size_t index;
-        for (index = 0; index < m_sub_requests_pending.size(); index++) {
-            if (&m_sub_requests_pending[index] == &sub_request) {
-                NonnullRefPtr<AsyncDeviceRequest> request(m_sub_requests_pending[index]);
-                m_sub_requests_pending.remove(index);
-                m_sub_requests_complete.append(move(request));
-                break;
-            }
-        }
-        ASSERT(index < m_sub_requests_pending.size());
-        all_completed = m_sub_requests_pending.is_empty();
-        if (all_completed) {
-            // Aggregate any errors
-            bool any_failures = false;
-            bool any_memory_faults = false;
-            for (index = 0; index < m_sub_requests_complete.size(); index++) {
-                auto& sub_request = m_sub_requests_complete[index];
-                auto sub_result = sub_request.get_request_result();
-                ASSERT(is_completed_result(sub_result));
-                switch (sub_result) {
-                case Failure:
-                    any_failures = true;
-                    break;
-                case MemoryFault:
-                    any_memory_faults = true;
-                    break;
-                default:
-                    break;
-                }
-                if (any_failures && any_memory_faults)
-                    break; // Stop checking if all error conditions were found
-            }
-            if (any_failures)
-                m_result = Failure;
-            else if (any_memory_faults)
-                m_result = MemoryFault;
-            else
-                m_result = Success;
-        }
-    }
-    if (all_completed)
-        request_finished();
-}
-
-void AsyncDeviceRequest::complete(RequestResult result)
-{
-    ASSERT(result == Success || result == Failure || result == MemoryFault);
-    ScopedCritical critical;
-    {
-        ScopedSpinLock lock(m_lock);
-        ASSERT(m_result == Started);
-        m_result = result;
-    }
-    if (Processor::current().in_irq()) {
-        ref(); // Make sure we don't get freed
-        Processor::deferred_call_queue([this]() {
-            request_finished();
-            unref();
-        });
-    } else {
-        request_finished();
-    }
-}
-
-}
diff --git a/Kernel/Devices/AsyncDeviceRequest.h b/Kernel/Devices/AsyncDeviceRequest.h
deleted file mode 100644
index 7d8010bd33..0000000000
--- a/Kernel/Devices/AsyncDeviceRequest.h
+++ /dev/null
@@ -1,175 +0,0 @@
-/*
- * Copyright (c) 2020, The SerenityOS developers.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- *    this list of conditions and the following disclaimer in the documentation
- *    and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
- * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#pragma once
-
-#include <AK/NonnullRefPtrVector.h>
-#include <Kernel/Process.h>
-#include <Kernel/Thread.h>
-#include <Kernel/UserOrKernelBuffer.h>
-#include <Kernel/VM/ProcessPagingScope.h>
-#include <Kernel/WaitQueue.h>
-
-namespace Kernel {
-
-class Device;
-
-class AsyncDeviceRequest : public RefCounted<AsyncDeviceRequest> {
-    AK_MAKE_NONCOPYABLE(AsyncDeviceRequest);
-    AK_MAKE_NONMOVABLE(AsyncDeviceRequest);
-
-public:
-    enum RequestResult {
-        Pending = 0,
-        Started,
-        Success,
-        Failure,
-        MemoryFault,
-        Cancelled
-    };
-
-    class RequestWaitResult {
-        friend class AsyncDeviceRequest;
-
-    public:
-        RequestResult request_result() const { return m_request_result; }
-        Thread::BlockResult wait_result() const { return m_wait_result; }
-
-    private:
-        RequestWaitResult(RequestResult request_result, Thread::BlockResult wait_result)
-            : m_request_result(request_result)
-            , m_wait_result(wait_result)
-        {
-        }
-
-        RequestResult m_request_result;
-        Thread::BlockResult m_wait_result;
-    };
-
-    virtual ~AsyncDeviceRequest();
-
-    virtual const char* name() const = 0;
-    virtual void start() = 0;
-
-    void add_sub_request(NonnullRefPtr<AsyncDeviceRequest>);
-
-    [[nodiscard]] RequestWaitResult wait(timeval* = nullptr);
-
-    void do_start(Badge<Device>)
-    {
-        do_start();
-    }
-
-    void complete(RequestResult result);
-
-    void set_private(void* priv)
-    {
-        ASSERT(!m_private || !priv);
-        m_private = priv;
-    }
-    void* get_private() const { return m_private; }
-
-    template<typename... Args>
-    [[nodiscard]] bool write_to_buffer(UserOrKernelBuffer& buffer, Args... args)
-    {
-        if (in_target_context(buffer))
-            return buffer.write(forward<Args>(args)...);
-        ProcessPagingScope paging_scope(m_process);
-        return buffer.write(forward<Args>(args)...);
-    }
-
-    template<size_t BUFFER_BYTES, typename... Args>
-    [[nodiscard]] bool write_to_buffer_buffered(UserOrKernelBuffer& buffer, Args... args)
-    {
-        if (in_target_context(buffer))
-            return buffer.write_buffered<BUFFER_BYTES>(forward<Args>(args)...);
-        ProcessPagingScope paging_scope(m_process);
-        return buffer.write_buffered<BUFFER_BYTES>(forward<Args>(args)...);
-    }
-
-    template<typename... Args>
-    [[nodiscard]] bool read_from_buffer(const UserOrKernelBuffer& buffer, Args... args)
-    {
-        if (in_target_context(buffer))
-            return buffer.read(forward<Args>(args)...);
-        ProcessPagingScope paging_scope(m_process);
-        return buffer.read(forward<Args>(args)...);
-    }
-
-    template<size_t BUFFER_BYTES, typename... Args>
-    [[nodiscard]] bool read_from_buffer_buffered(const UserOrKernelBuffer& buffer, Args... args)
-    {
-        if (in_target_context(buffer))
-            return buffer.read_buffered<BUFFER_BYTES>(forward<Args>(args)...);
-        ProcessPagingScope paging_scope(m_process);
-        return buffer.read_buffered<BUFFER_BYTES>(forward<Args>(args)...);
-    }
-
-protected:
-    AsyncDeviceRequest(Device&);
-
-    RequestResult get_request_result() const;
-
-private:
-    void sub_request_finished(AsyncDeviceRequest&);
-    void request_finished();
-
-    void do_start()
-    {
-        {
-            ScopedSpinLock lock(m_lock);
-            if (is_completed_result(m_result))
-                return;
-            m_result = Started;
-        }
-        start();
-    }
-
-    bool in_target_context(const UserOrKernelBuffer& buffer) const
-    {
-        if (buffer.is_kernel_buffer())
-            return true;
-        return m_process == Process::current();
-    }
-
-    static bool is_completed_result(RequestResult result)
-    {
-        return result > Started;
-    }
-
-    Device& m_device;
-
-    AsyncDeviceRequest* m_parent_request { nullptr };
-    RequestResult m_result { Pending };
-    NonnullRefPtrVector<AsyncDeviceRequest> m_sub_requests_pending;
-    NonnullRefPtrVector<AsyncDeviceRequest> m_sub_requests_complete;
-    WaitQueue m_queue;
-    NonnullRefPtr<Process> m_process;
-    void* m_private { nullptr };
-    mutable SpinLock<u8> m_lock;
-};
-
-}
diff --git a/Kernel/Devices/BXVGADevice.h b/Kernel/Devices/BXVGADevice.h
index de3f4bfd72..6b98db525b 100644
--- a/Kernel/Devices/BXVGADevice.h
+++ b/Kernel/Devices/BXVGADevice.h
@@ -48,9 +48,10 @@ private:
     virtual const char* class_name() const override { return "BXVGA"; }
     virtual bool can_read(const FileDescription&, size_t) const override { return true; }
     virtual bool can_write(const FileDescription&, size_t) const override { return true; }
-    virtual void start_request(AsyncBlockDeviceRequest& request) override { request.complete(AsyncDeviceRequest::Failure); }
     virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override { return -EINVAL; }
     virtual KResultOr<size_t> write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t) override { return -EINVAL; }
+    virtual bool read_blocks(unsigned, u16, UserOrKernelBuffer&) override { return false; }
+    virtual bool write_blocks(unsigned, u16, const UserOrKernelBuffer&) override { return false; }
 
     void set_safe_resolution();
 
diff --git a/Kernel/Devices/BlockDevice.cpp b/Kernel/Devices/BlockDevice.cpp
index 9e24f2dba8..d1f70a14dd 100644
--- a/Kernel/Devices/BlockDevice.cpp
+++ b/Kernel/Devices/BlockDevice.cpp
@@ -28,66 +28,18 @@
 
 namespace Kernel {
 
-AsyncBlockDeviceRequest::AsyncBlockDeviceRequest(Device& block_device, RequestType request_type, u32 block_index, u32 block_count, const UserOrKernelBuffer& buffer, size_t buffer_size)
-    : AsyncDeviceRequest(block_device)
-    , m_block_device(static_cast<BlockDevice&>(block_device))
-    , m_request_type(request_type)
-    , m_block_index(block_index)
-    , m_block_count(block_count)
-    , m_buffer(buffer)
-    , m_buffer_size(buffer_size)
-{
-}
-
-void AsyncBlockDeviceRequest::start()
-{
-    m_block_device.start_request(*this);
-}
-
 BlockDevice::~BlockDevice()
 {
 }
 
-bool BlockDevice::read_block(unsigned index, UserOrKernelBuffer& buffer)
+bool BlockDevice::read_block(unsigned index, UserOrKernelBuffer& buffer) const
 {
-    auto read_request = make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Read, index, 1, buffer, 512);
-    switch (read_request->wait().request_result()) {
-    case AsyncDeviceRequest::Success:
-        return true;
-    case AsyncDeviceRequest::Failure:
-        dbg() << "BlockDevice::read_block(" << index << ") IO error";
-        break;
-    case AsyncDeviceRequest::MemoryFault:
-        dbg() << "BlockDevice::read_block(" << index << ") EFAULT";
-        break;
-    case AsyncDeviceRequest::Cancelled:
-        dbg() << "BlockDevice::read_block(" << index << ") cancelled";
-        break;
-    default:
-        ASSERT_NOT_REACHED();
-    }
-    return false;
+    return const_cast<BlockDevice*>(this)->read_blocks(index, 1, buffer);
 }
 
-bool BlockDevice::write_block(unsigned index, const UserOrKernelBuffer& buffer)
+bool BlockDevice::write_block(unsigned index, const UserOrKernelBuffer& data)
 {
-    auto write_request = make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Write, index, 1, buffer, 512);
-    switch (write_request->wait().request_result()) {
-    case AsyncDeviceRequest::Success:
-        return true;
-    case AsyncDeviceRequest::Failure:
-        dbg() << "BlockDevice::write_block(" << index << ") IO error";
-        break;
-    case AsyncDeviceRequest::MemoryFault:
-        dbg() << "BlockDevice::write_block(" << index << ") EFAULT";
-        break;
-    case AsyncDeviceRequest::Cancelled:
-        dbg() << "BlockDevice::write_block(" << index << ") cancelled";
-        break;
-    default:
-        ASSERT_NOT_REACHED();
-    }
-    return false;
+    return write_blocks(index, 1, data);
 }
 
 }
diff --git a/Kernel/Devices/BlockDevice.h b/Kernel/Devices/BlockDevice.h
index 975f46b7a8..ee9a5bbead 100644
--- a/Kernel/Devices/BlockDevice.h
+++ b/Kernel/Devices/BlockDevice.h
@@ -30,46 +30,6 @@
 
 namespace Kernel {
 
-class BlockDevice;
-
-class AsyncBlockDeviceRequest : public AsyncDeviceRequest {
-public:
-    enum RequestType {
-        Read,
-        Write
-    };
-    AsyncBlockDeviceRequest(Device& block_device, RequestType request_type,
-        u32 block_index, u32 block_count, const UserOrKernelBuffer& buffer, size_t buffer_size);
-
-    RequestType request_type() const { return m_request_type; }
-    u32 block_index() const { return m_block_index; }
-    u32 block_count() const { return m_block_count; }
-    UserOrKernelBuffer& buffer() { return m_buffer; }
-    const UserOrKernelBuffer& buffer() const { return m_buffer; }
-    size_t buffer_size() const { return m_buffer_size; }
-
-    virtual void start() override;
-    virtual const char* name() const override
-    {
-        switch (m_request_type) {
-        case Read:
-            return "BlockDeviceRequest (read)";
-        case Write:
-            return "BlockDeviceRequest (read)";
-        default:
-            ASSERT_NOT_REACHED();
-        }
-    }
-
-private:
-    BlockDevice& m_block_device;
-    const RequestType m_request_type;
-    const u32 m_block_index;
-    const u32 m_block_count;
-    UserOrKernelBuffer m_buffer;
-    const size_t m_buffer_size;
-};
-
 class BlockDevice : public Device {
 public:
     virtual ~BlockDevice() override;
@@ -77,10 +37,11 @@ public:
     size_t block_size() const { return m_block_size; }
     virtual bool is_seekable() const override { return true; }
 
-    bool read_block(unsigned index, UserOrKernelBuffer&);
+    bool read_block(unsigned index, UserOrKernelBuffer&) const;
     bool write_block(unsigned index, const UserOrKernelBuffer&);
 
-    virtual void start_request(AsyncBlockDeviceRequest&) = 0;
+    virtual bool read_blocks(unsigned index, u16 count, UserOrKernelBuffer&) = 0;
+    virtual bool write_blocks(unsigned index, u16 count, const UserOrKernelBuffer&) = 0;
 
 protected:
     BlockDevice(unsigned major, unsigned minor, size_t block_size = PAGE_SIZE)
diff --git a/Kernel/Devices/Device.cpp b/Kernel/Devices/Device.cpp
index eda56e1cfe..934c587ba6 100644
--- a/Kernel/Devices/Device.cpp
+++ b/Kernel/Devices/Device.cpp
@@ -80,21 +80,4 @@ String Device::absolute_path(const FileDescription&) const
     return absolute_path();
 }
 
-void Device::process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest& completed_request)
-{
-    AsyncDeviceRequest* next_request = nullptr;
-
-    {
-        ScopedSpinLock lock(m_requests_lock);
-        ASSERT(!m_requests.is_empty());
-        ASSERT(m_requests.first().ptr() == &completed_request);
-        m_requests.remove(m_requests.begin());
-        if (!m_requests.is_empty())
-            next_request = m_requests.first().ptr();
-    }
-
-    if (next_request)
-        next_request->start();
-}
-
 }
diff --git a/Kernel/Devices/Device.h b/Kernel/Devices/Device.h
index 80a63e22a8..8fa97a02ab 100644
--- a/Kernel/Devices/Device.h
+++ b/Kernel/Devices/Device.h
@@ -34,12 +34,10 @@
 // There are two main subclasses:
 //   - BlockDevice (random access)
 //   - CharacterDevice (sequential)
-#include <AK/DoublyLinkedList.h>
 #include <AK/Function.h>
 #include <AK/HashMap.h>
-#include <Kernel/Devices/AsyncDeviceRequest.h>
+#include <Kernel/Arch/i386/CPU.h>
 #include <Kernel/FileSystem/File.h>
-#include <Kernel/Lock.h>
 #include <Kernel/UnixTypes.h>
 
 namespace Kernel {
@@ -63,23 +61,6 @@ public:
     static void for_each(Function<void(Device&)>);
     static Device* get_device(unsigned major, unsigned minor);
 
-    void process_next_queued_request(Badge<AsyncDeviceRequest>, const AsyncDeviceRequest&);
-
-    template<typename AsyncRequestType, typename... Args>
-    NonnullRefPtr<AsyncRequestType> make_request(Args&&... args)
-    {
-        auto request = adopt(*new AsyncRequestType(*this, forward<Args>(args)...));
-        bool was_empty;
-        {
-            ScopedSpinLock lock(m_requests_lock);
-            was_empty = m_requests.is_empty();
-            m_requests.append(request);
-        }
-        if (was_empty)
-            request->do_start({});
-        return request;
-    }
-
 protected:
     Device(unsigned major, unsigned minor);
     void set_uid(uid_t uid) { m_uid = uid; }
@@ -92,9 +73,6 @@ private:
     unsigned m_minor { 0 };
     uid_t m_uid { 0 };
     gid_t m_gid { 0 };
-
-    SpinLock<u8> m_requests_lock;
-    DoublyLinkedList<RefPtr<AsyncDeviceRequest>> m_requests;
 };
 
 }
diff --git a/Kernel/Devices/DiskPartition.cpp b/Kernel/Devices/DiskPartition.cpp
index d07961f74c..d1ccb90d1b 100644
--- a/Kernel/Devices/DiskPartition.cpp
+++ b/Kernel/Devices/DiskPartition.cpp
@@ -48,12 +48,6 @@ DiskPartition::~DiskPartition()
 {
 }
 
-void DiskPartition::start_request(AsyncBlockDeviceRequest& request)
-{
-    request.add_sub_request(m_device->make_request<AsyncBlockDeviceRequest>(request.request_type(),
-        request.block_index() + m_block_offset, request.block_count(), request.buffer(), request.buffer_size()));
-}
-
 KResultOr<size_t> DiskPartition::read(FileDescription& fd, size_t offset, UserOrKernelBuffer& outbuf, size_t len)
 {
     unsigned adjust = m_block_offset * block_size();
@@ -98,6 +92,24 @@ bool DiskPartition::can_write(const FileDescription& fd, size_t offset) const
     return m_device->can_write(fd, offset + adjust);
 }
 
+bool DiskPartition::read_blocks(unsigned index, u16 count, UserOrKernelBuffer& out)
+{
+#ifdef OFFD_DEBUG
+    klog() << "DiskPartition::read_blocks " << index << " (really: " << (m_block_offset + index) << ") count=" << count;
+#endif
+
+    return m_device->read_blocks(m_block_offset + index, count, out);
+}
+
+bool DiskPartition::write_blocks(unsigned index, u16 count, const UserOrKernelBuffer& data)
+{
+#ifdef OFFD_DEBUG
+    klog() << "DiskPartition::write_blocks " << index << " (really: " << (m_block_offset + index) << ") count=" << count;
+#endif
+
+    return m_device->write_blocks(m_block_offset + index, count, data);
+}
+
 const char* DiskPartition::class_name() const
 {
     return "DiskPartition";
diff --git a/Kernel/Devices/DiskPartition.h b/Kernel/Devices/DiskPartition.h
index 7d37354960..e9551b8097 100644
--- a/Kernel/Devices/DiskPartition.h
+++ b/Kernel/Devices/DiskPartition.h
@@ -36,7 +36,8 @@ public:
     static NonnullRefPtr<DiskPartition> create(BlockDevice&, unsigned block_offset, unsigned block_limit);
     virtual ~DiskPartition();
 
-    virtual void start_request(AsyncBlockDeviceRequest&) override;
+    virtual bool read_blocks(unsigned index, u16 count, UserOrKernelBuffer&) override;
+    virtual bool write_blocks(unsigned index, u16 count, const UserOrKernelBuffer&) override;
 
     // ^BlockDevice
     virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override;
diff --git a/Kernel/Devices/EBRPartitionTable.cpp b/Kernel/Devices/EBRPartitionTable.cpp
index 6cdd52fb8a..bfaf999162 100644
--- a/Kernel/Devices/EBRPartitionTable.cpp
+++ b/Kernel/Devices/EBRPartitionTable.cpp
@@ -63,9 +63,6 @@ int EBRPartitionTable::index_of_ebr_container() const
 
 bool EBRPartitionTable::initialize()
 {
-    auto mbr_header_request = m_device->make_request<AsyncBlockDeviceRequest>(AsyncBlockDeviceRequest::Read,
-        0, 1, UserOrKernelBuffer::for_kernel_buffer(m_cached_mbr_header), sizeof(m_cached_mbr_header));
-
     auto mbr_header_buffer = UserOrKernelBuffer::for_kernel_buffer(m_cached_mbr_header);
     if (!m_device->read_block(0, mbr_header_buffer)) {
         return false;
diff --git a/Kernel/Devices/GPTPartitionTable.cpp b/Kernel/Devices/GPTPartitionTable.cpp
index 019f8994e1..9031269031 100644
--- a/Kernel/Devices/GPTPartitionTable.cpp
+++ b/Kernel/Devices/GPTPartitionTable.cpp
@@ -84,7 +84,7 @@ RefPtr<DiskPartition> GPTPartitionTable::partition(unsigned index)
 
     GPTPartitionEntry entries[entries_per_sector];
     auto entries_buffer = UserOrKernelBuffer::for_kernel_buffer((u8*)&entries);
-    this->m_device->read_block(lba, entries_buffer);
+    this->m_device->read_blocks(lba, 1, entries_buffer);
     GPTPartitionEntry& entry = entries[((index - 1) % entries_per_sector)];
 
 #ifdef GPT_DEBUG
diff --git a/Kernel/Devices/MBVGADevice.h b/Kernel/Devices/MBVGADevice.h
index 9ee9d762ae..09dda1f853 100644
--- a/Kernel/Devices/MBVGADevice.h
+++ b/Kernel/Devices/MBVGADevice.h
@@ -49,7 +49,8 @@ private:
     virtual bool can_write(const FileDescription&, size_t) const override { return true; }
     virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override { return -EINVAL; }
     virtual KResultOr<size_t> write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t) override { return -EINVAL; }
-    virtual void start_request(AsyncBlockDeviceRequest& request) override { request.complete(AsyncDeviceRequest::Failure); }
+    virtual bool read_blocks(unsigned, u16, UserOrKernelBuffer&) override { return false; }
+    virtual bool write_blocks(unsigned, u16, const UserOrKernelBuffer&) override { return false; }
 
     size_t framebuffer_size_in_bytes() const { return m_framebuffer_pitch * m_framebuffer_height; }
 
diff --git a/Kernel/Devices/PATAChannel.cpp b/Kernel/Devices/PATAChannel.cpp
index d4f32096c1..cc47ff532c 100644
--- a/Kernel/Devices/PATAChannel.cpp
+++ b/Kernel/Devices/PATAChannel.cpp
@@ -108,6 +108,13 @@ namespace Kernel {
 #define PCI_Mass_Storage_Class 0x1
 #define PCI_IDE_Controller_Subclass 0x1
 
+static AK::Singleton<Lock> s_pata_lock;
+
+static Lock& s_lock()
+{
+    return *s_pata_lock;
+};
+
 OwnPtr<PATAChannel> PATAChannel::create(ChannelType type, bool force_pio)
 {
     PCI::Address pci_address;
@@ -141,59 +148,10 @@ PATAChannel::~PATAChannel()
 {
 }
 
-void PATAChannel::start_request(AsyncBlockDeviceRequest& request, bool use_dma, bool is_slave)
+void PATAChannel::prepare_for_irq()
 {
-    m_current_request = &request;
-    m_current_request_block_index = 0;
-    m_current_request_uses_dma = use_dma;
-    m_current_request_flushing_cache = false;
-
-    if (request.request_type() == AsyncBlockDeviceRequest::Read) {
-        if (use_dma)
-            ata_read_sectors_with_dma(is_slave);
-        else
-            ata_read_sectors(is_slave);
-    } else {
-        if (use_dma)
-            ata_write_sectors_with_dma(is_slave);
-        else
-            ata_write_sectors(is_slave);
-    }
-}
-
-void PATAChannel::complete_current_request(AsyncDeviceRequest::RequestResult result)
-{
-    // NOTE: this may be called from the interrupt handler!
-    ASSERT(m_current_request);
-
-    // Now schedule reading back the buffer as soon as we leave the irq handler.
-    // This is important so that we can safely write the buffer back,
-    // which could cause page faults. Note that this may be called immediately
-    // before Processor::deferred_call_queue returns!
-    Processor::deferred_call_queue([this, result]() {
-#ifdef PATA_DEBUG
-        dbg() << "PATAChannel::complete_current_request result: " << result;
-#endif
-        ASSERT(m_current_request);
-        auto& request = *m_current_request;
-        m_current_request = nullptr;
-
-        if (m_current_request_uses_dma) {
-            if (result == AsyncDeviceRequest::Success) {
-                if (request.request_type() == AsyncBlockDeviceRequest::Read) {
-                    if (!request.write_to_buffer(request.buffer(), m_dma_buffer_page->paddr().offset(0xc0000000).as_ptr(), 512 * request.block_count())) {
-                        request.complete(AsyncDeviceRequest::MemoryFault);
-                        return;
-                    }
-                }
-
-                // I read somewhere that this may trigger a cache flush so let's do it.
-                m_bus_master_base.offset(2).out<u8>(m_bus_master_base.offset(2).in<u8>() | 0x6);
-            }
-        }
-
-        request.complete(result);
-    });
+    cli();
+    enable_irq();
 }
 
 void PATAChannel::initialize(bool force_pio)
@@ -217,6 +175,12 @@ static void print_ide_status(u8 status)
     klog() << "PATAChannel: print_ide_status: DRQ=" << ((status & ATA_SR_DRQ) != 0) << " BSY=" << ((status & ATA_SR_BSY) != 0) << " DRDY=" << ((status & ATA_SR_DRDY) != 0) << " DSC=" << ((status & ATA_SR_DSC) != 0) << " DF=" << ((status & ATA_SR_DF) != 0) << " CORR=" << ((status & ATA_SR_CORR) != 0) << " IDX=" << ((status & ATA_SR_IDX) != 0) << " ERR=" << ((status & ATA_SR_ERR) != 0);
 }
 
+void PATAChannel::wait_for_irq()
+{
+    Thread::current()->wait_on(m_irq_queue, "PATAChannel");
+    disable_irq();
+}
+
 void PATAChannel::handle_irq(const RegisterState&)
 {
     u8 status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
@@ -232,63 +196,16 @@ void PATAChannel::handle_irq(const RegisterState&)
         return;
     }
 
-#ifdef PATA_DEBUG
-    klog() << "PATAChannel: interrupt: DRQ=" << ((status & ATA_SR_DRQ) != 0) << " BSY=" << ((status & ATA_SR_BSY) != 0) << " DRDY=" << ((status & ATA_SR_DRDY) != 0);
-#endif
-
-    bool received_all_irqs = m_current_request_uses_dma || m_current_request_block_index + 1 >= m_current_request->block_count();
-
-    disable_irq();
-
     if (status & ATA_SR_ERR) {
         print_ide_status(status);
         m_device_error = m_io_base.offset(ATA_REG_ERROR).in<u8>();
         klog() << "PATAChannel: Error " << String::format("%b", m_device_error) << "!";
-        complete_current_request(AsyncDeviceRequest::Failure);
-        return;
-    }
-
-    m_device_error = 0;
-    if (received_all_irqs) {
-        complete_current_request(AsyncDeviceRequest::Success);
     } else {
-        ASSERT(!m_current_request_uses_dma);
-
-        // Now schedule reading/writing the buffer as soon as we leave the irq handler.
-        // This is important so that we can safely access the buffers, which could
-        // trigger page faults
-        Processor::deferred_call_queue([this]() {
-            if (m_current_request->request_type() == AsyncBlockDeviceRequest::Read) {
-                dbg() << "PATAChannel: Read block " << m_current_request_block_index << "/" << m_current_request->block_count();
-                if (ata_do_read_sector()) {
-                    if (++m_current_request_block_index >= m_current_request->block_count()) {
-                        complete_current_request(AsyncDeviceRequest::Success);
-                        return;
-                    }
-                    // Wait for the next block
-                    enable_irq();
-                }
-            } else {
-                if (!m_current_request_flushing_cache) {
-                    dbg() << "PATAChannel: Wrote block " << m_current_request_block_index << "/" << m_current_request->block_count();
-                    if (++m_current_request_block_index >= m_current_request->block_count()) {
-                        // We read the last block, flush cache
-                        ASSERT(!m_current_request_flushing_cache);
-                        m_current_request_flushing_cache = true;
-                        enable_irq();
-                        m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_CACHE_FLUSH);
-                    } else {
-                        // Read next block
-                        enable_irq();
-                        ata_do_write_sector();
-                    }
-                } else {
-                    complete_current_request(AsyncDeviceRequest::Success);
-                }
-            }
-        });
+        m_device_error = 0;
     }
-
+#ifdef PATA_DEBUG
+    klog() << "PATAChannel: interrupt: DRQ=" << ((status & ATA_SR_DRQ) != 0) << " BSY=" << ((status & ATA_SR_BSY) != 0) << " DRDY=" << ((status & ATA_SR_DRDY) != 0);
+#endif
     m_irq_queue.wake_all();
 }
 
@@ -357,16 +274,15 @@ void PATAChannel::detect_disks()
     }
 }
 
-void PATAChannel::ata_read_sectors_with_dma(bool slave_request)
+bool PATAChannel::ata_read_sectors_with_dma(u32 lba, u16 count, UserOrKernelBuffer& outbuf, bool slave_request)
 {
-    auto& request = *m_current_request;
-    u32 lba = request.block_index();
+    LOCKER(s_lock());
 #ifdef PATA_DEBUG
-    dbg() << "PATAChannel::ata_read_sectors_with_dma (" << lba << " x" << request.block_count() << ")";
+    dbg() << "PATAChannel::ata_read_sectors_with_dma (" << lba << " x" << count << ") -> " << outbuf.user_or_kernel_ptr();
 #endif
 
     prdt().offset = m_dma_buffer_page->paddr();
-    prdt().size = 512 * request.block_count();
+    prdt().size = 512 * count;
 
     ASSERT(prdt().size <= PAGE_SIZE);
 
@@ -396,7 +312,7 @@ void PATAChannel::ata_read_sectors_with_dma(bool slave_request)
     m_io_base.offset(ATA_REG_LBA1).out<u8>(0);
     m_io_base.offset(ATA_REG_LBA2).out<u8>(0);
 
-    m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(request.block_count());
+    m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(count);
     m_io_base.offset(ATA_REG_LBA0).out<u8>((lba & 0x000000ff) >> 0);
     m_io_base.offset(ATA_REG_LBA1).out<u8>((lba & 0x0000ff00) >> 8);
     m_io_base.offset(ATA_REG_LBA2).out<u8>((lba & 0x00ff0000) >> 16);
@@ -410,60 +326,62 @@ void PATAChannel::ata_read_sectors_with_dma(bool slave_request)
     m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_READ_DMA_EXT);
     io_delay();
 
-    enable_irq();
+    prepare_for_irq();
     // Start bus master
     m_bus_master_base.out<u8>(0x9);
-}
 
-bool PATAChannel::ata_do_read_sector()
-{
-    auto& request = *m_current_request;
-    auto out_buffer = request.buffer().offset(m_current_request_block_index * 512);
-    ssize_t nwritten = request.write_to_buffer_buffered<512>(out_buffer, 512, [&](u8* buffer, size_t buffer_bytes) {
-        for (size_t i = 0; i < buffer_bytes; i += sizeof(u16))
-            *(u16*)&buffer[i] = IO::in16(m_io_base.offset(ATA_REG_DATA).get());
-        return (ssize_t)buffer_bytes;
-    });
-    if (nwritten < 0) {
-        // TODO: Do we need to abort the PATA read if this wasn't the last block?
-        complete_current_request(AsyncDeviceRequest::MemoryFault);
+    wait_for_irq();
+
+    if (m_device_error)
         return false;
-    }
+
+    if (!outbuf.write(m_dma_buffer_page->paddr().offset(0xc0000000).as_ptr(), 512 * count))
+        return false; // TODO: -EFAULT
+
+    // I read somewhere that this may trigger a cache flush so let's do it.
+    m_bus_master_base.offset(2).out<u8>(m_bus_master_base.offset(2).in<u8>() | 0x6);
     return true;
 }
 
-void PATAChannel::ata_read_sectors(bool slave_request)
+bool PATAChannel::ata_write_sectors_with_dma(u32 lba, u16 count, const UserOrKernelBuffer& inbuf, bool slave_request)
 {
-    auto& request = *m_current_request;
-    ASSERT(request.block_count() <= 256);
+    LOCKER(s_lock());
 #ifdef PATA_DEBUG
-    dbg() << "PATAChannel::ata_read_sectors";
+    dbg() << "PATAChannel::ata_write_sectors_with_dma (" << lba << " x" << count << ") <- " << inbuf.user_or_kernel_ptr();
 #endif
 
-    while (m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY)
-        ;
+    prdt().offset = m_dma_buffer_page->paddr();
+    prdt().size = 512 * count;
 
-    auto lba = request.block_index();
-#ifdef PATA_DEBUG
-    klog() << "PATAChannel: Reading " << request.block_count() << " sector(s) @ LBA " << lba;
-#endif
+    if (!inbuf.read(m_dma_buffer_page->paddr().offset(0xc0000000).as_ptr(), 512 * count))
+        return false; // TODO: -EFAULT
 
-    u8 devsel = 0xe0;
-    if (slave_request)
-        devsel |= 0x10;
+    ASSERT(prdt().size <= PAGE_SIZE);
+
+    // Stop bus master
+    m_bus_master_base.out<u8>(0);
+
+    // Write the PRDT location
+    m_bus_master_base.offset(4).out<u32>(m_prdt_page->paddr().get());
+
+    // Turn on "Interrupt" and "Error" flag. The error flag should be cleared by hardware.
+    m_bus_master_base.offset(2).out<u8>(m_bus_master_base.offset(2).in<u8>() | 0x6);
+
+    while (m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY)
+        ;
 
     m_control_base.offset(ATA_CTL_CONTROL).out<u8>(0);
-    m_io_base.offset(ATA_REG_HDDEVSEL).out<u8>(devsel | (static_cast<u8>(slave_request) << 4) | 0x40);
+    m_io_base.offset(ATA_REG_HDDEVSEL).out<u8>(0x40 | (static_cast<u8>(slave_request) << 4));
     io_delay();
 
-    m_io_base.offset(ATA_REG_FEATURES).out<u8>(0);
+    m_io_base.offset(ATA_REG_FEATURES).out<u16>(0);
 
     m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(0);
     m_io_base.offset(ATA_REG_LBA0).out<u8>(0);
     m_io_base.offset(ATA_REG_LBA1).out<u8>(0);
     m_io_base.offset(ATA_REG_LBA2).out<u8>(0);
 
-    m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(request.block_count());
+    m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(count);
     m_io_base.offset(ATA_REG_LBA0).out<u8>((lba & 0x000000ff) >> 0);
     m_io_base.offset(ATA_REG_LBA1).out<u8>((lba & 0x0000ff00) >> 8);
     m_io_base.offset(ATA_REG_LBA2).out<u8>((lba & 0x00ff0000) >> 16);
@@ -474,52 +392,53 @@ void PATAChannel::ata_read_sectors(bool slave_request)
             break;
     }
 
-    enable_irq();
-    m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_READ_PIO);
+    m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_WRITE_DMA_EXT);
+    io_delay();
+
+    prepare_for_irq();
+    // Start bus master
+    m_bus_master_base.out<u8>(0x1);
+    wait_for_irq();
+
+    if (m_device_error)
+        return false;
+
+    // I read somewhere that this may trigger a cache flush so let's do it.
+    m_bus_master_base.offset(2).out<u8>(m_bus_master_base.offset(2).in<u8>() | 0x6);
+    return true;
 }
 
-void PATAChannel::ata_write_sectors_with_dma(bool slave_request)
+bool PATAChannel::ata_read_sectors(u32 lba, u16 count, UserOrKernelBuffer& outbuf, bool slave_request)
 {
-    auto& request = *m_current_request;
-    u32 lba = request.block_index();
+    ASSERT(count <= 256);
+    LOCKER(s_lock());
 #ifdef PATA_DEBUG
-    dbg() << "PATAChannel::ata_write_sectors_with_dma (" << lba << " x" << request.block_count() << ")";
+    dbg() << "PATAChannel::ata_read_sectors request (" << count << " sector(s) @ " << lba << " into " << outbuf.user_or_kernel_ptr() << ")";
 #endif
 
-    prdt().offset = m_dma_buffer_page->paddr();
-    prdt().size = 512 * request.block_count();
-
-    if (!request.read_from_buffer(request.buffer(), m_dma_buffer_page->paddr().offset(0xc0000000).as_ptr(), 512 * request.block_count())) {
-        complete_current_request(AsyncDeviceRequest::MemoryFault);
-        return;
-    }
-
-    ASSERT(prdt().size <= PAGE_SIZE);
-
-    // Stop bus master
-    m_bus_master_base.out<u8>(0);
-
-    // Write the PRDT location
-    m_bus_master_base.offset(4).out<u32>(m_prdt_page->paddr().get());
-
-    // Turn on "Interrupt" and "Error" flag. The error flag should be cleared by hardware.
-    m_bus_master_base.offset(2).out<u8>(m_bus_master_base.offset(2).in<u8>() | 0x6);
-
     while (m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY)
         ;
 
+#ifdef PATA_DEBUG
+    klog() << "PATAChannel: Reading " << count << " sector(s) @ LBA " << lba;
+#endif
+
+    u8 devsel = 0xe0;
+    if (slave_request)
+        devsel |= 0x10;
+
     m_control_base.offset(ATA_CTL_CONTROL).out<u8>(0);
-    m_io_base.offset(ATA_REG_HDDEVSEL).out<u8>(0x40 | (static_cast<u8>(slave_request) << 4));
+    m_io_base.offset(ATA_REG_HDDEVSEL).out<u8>(devsel | (static_cast<u8>(slave_request) << 4) | 0x40);
     io_delay();
 
-    m_io_base.offset(ATA_REG_FEATURES).out<u16>(0);
+    m_io_base.offset(ATA_REG_FEATURES).out<u8>(0);
 
     m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(0);
     m_io_base.offset(ATA_REG_LBA0).out<u8>(0);
     m_io_base.offset(ATA_REG_LBA1).out<u8>(0);
     m_io_base.offset(ATA_REG_LBA2).out<u8>(0);
 
-    m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(request.block_count());
+    m_io_base.offset(ATA_REG_SECCOUNT0).out<u8>(count);
     m_io_base.offset(ATA_REG_LBA0).out<u8>((lba & 0x000000ff) >> 0);
     m_io_base.offset(ATA_REG_LBA1).out<u8>((lba & 0x0000ff00) >> 8);
     m_io_base.offset(ATA_REG_LBA2).out<u8>((lba & 0x00ff0000) >> 16);
@@ -530,45 +449,46 @@ void PATAChannel::ata_write_sectors_with_dma(bool slave_request)
             break;
     }
 
-    m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_WRITE_DMA_EXT);
-    io_delay();
-
-    enable_irq();
-    // Start bus master
-    m_bus_master_base.out<u8>(0x1);
-}
-
-void PATAChannel::ata_do_write_sector()
-{
-    auto& request = *m_current_request;
+    prepare_for_irq();
+    m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_READ_PIO);
 
-    io_delay();
-    while ((m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY) || !(m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_DRQ))
-        ;
+    for (int i = 0; i < count; i++) {
+        if (i > 0)
+            prepare_for_irq();
+        wait_for_irq();
+        if (m_device_error)
+            return false;
 
-    u8 status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
-    ASSERT(status & ATA_SR_DRQ);
+        u8 status = m_control_base.offset(ATA_CTL_ALTSTATUS).in<u8>();
+        ASSERT(!(status & ATA_SR_BSY));
 
-    auto in_buffer = request.buffer().offset(m_current_request_block_index * 512);
+        auto out = outbuf.offset(i * 512);
 #ifdef PATA_DEBUG
-    dbg() << "PATAChannel: Writing 512 bytes (part " << m_current_request_block_index << ") (status=" << String::format("%b", status) << ")...";
+        dbg() << "PATAChannel: Retrieving 512 bytes (part " << i << ") (status=" << String::format("%b", status) << "), outbuf=(" << out.user_or_kernel_ptr() << ")...";
 #endif
-    ssize_t nread = request.read_from_buffer_buffered<512>(in_buffer, 512, [&](const u8* buffer, size_t buffer_bytes) {
-        for (size_t i = 0; i < buffer_bytes; i += sizeof(u16))
-            IO::out16(m_io_base.offset(ATA_REG_DATA).get(), *(const u16*)&buffer[i]);
-        return (ssize_t)buffer_bytes;
-    });
-    if (nread < 0)
-        complete_current_request(AsyncDeviceRequest::MemoryFault);
+        prepare_for_irq();
+
+        ssize_t nwritten = out.write_buffered<512>(512, [&](u8* buffer, size_t buffer_bytes) {
+            for (size_t i = 0; i < buffer_bytes; i += sizeof(u16))
+                *(u16*)&buffer[i] = IO::in16(m_io_base.offset(ATA_REG_DATA).get());
+            return (ssize_t)buffer_bytes;
+        });
+        if (nwritten < 0) {
+            sti();
+            disable_irq();
+            return false; // TODO: -EFAULT
+        }
+    }
+
+    sti();
+    disable_irq();
+    return true;
 }
 
-void PATAChannel::ata_write_sectors(bool slave_request)
+bool PATAChannel::ata_write_sectors(u32 start_sector, u16 count, const UserOrKernelBuffer& inbuf, bool slave_request)
 {
-    auto& request = *m_current_request;
-
-    ASSERT(request.block_count() <= 256);
-    u32 start_sector = request.block_index();
-    u32 count = request.block_count();
+    ASSERT(count <= 256);
+    LOCKER(s_lock());
 #ifdef PATA_DEBUG
     klog() << "PATAChannel::ata_write_sectors request (" << count << " sector(s) @ " << start_sector << ")";
 #endif
@@ -596,12 +516,37 @@ void PATAChannel::ata_write_sectors(bool slave_request)
 
     m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_WRITE_PIO);
 
-    io_delay();
-    while ((m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY) || !(m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_DRQ))
-        ;
+    for (int i = 0; i < count; i++) {
+        io_delay();
+        while ((m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_BSY) || !(m_io_base.offset(ATA_REG_STATUS).in<u8>() & ATA_SR_DRQ))
+            ;
 
-    enable_irq();
-    ata_do_write_sector();
+        u8 status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
+        ASSERT(status & ATA_SR_DRQ);
+
+        auto in = inbuf.offset(i * 512);
+#ifdef PATA_DEBUG
+        dbg() << "PATAChannel: Writing 512 bytes (part " << i << ") (status=" << String::format("%b", status) << "), inbuf=(" << in.user_or_kernel_ptr() << ")...";
+#endif
+        prepare_for_irq();
+        ssize_t nread = in.read_buffered<512>(512, [&](const u8* buffer, size_t buffer_bytes) {
+            for (size_t i = 0; i < buffer_bytes; i += sizeof(u16))
+                IO::out16(m_io_base.offset(ATA_REG_DATA).get(), *(const u16*)&buffer[i]);
+            return (ssize_t)buffer_bytes;
+        });
+        wait_for_irq();
+        status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
+        ASSERT(!(status & ATA_SR_BSY));
+        if (nread < 0)
+            return false; // TODO: -EFAULT
+    }
+    prepare_for_irq();
+    m_io_base.offset(ATA_REG_COMMAND).out<u8>(ATA_CMD_CACHE_FLUSH);
+    wait_for_irq();
+    u8 status = m_io_base.offset(ATA_REG_STATUS).in<u8>();
+    ASSERT(!(status & ATA_SR_BSY));
+
+    return !m_device_error;
 }
 
 }
diff --git a/Kernel/Devices/PATAChannel.h b/Kernel/Devices/PATAChannel.h
index 033598ae5e..40e331a4e8 100644
--- a/Kernel/Devices/PATAChannel.h
+++ b/Kernel/Devices/PATAChannel.h
@@ -39,7 +39,6 @@
 
 #include <AK/OwnPtr.h>
 #include <AK/RefPtr.h>
-#include <Kernel/Devices/Device.h>
 #include <Kernel/IO.h>
 #include <Kernel/Lock.h>
 #include <Kernel/PCI/Access.h>
@@ -51,8 +50,6 @@
 
 namespace Kernel {
 
-class AsyncBlockDeviceRequest;
-
 struct PhysicalRegionDescriptor {
     PhysicalAddress offset;
     u16 size { 0 };
@@ -86,15 +83,13 @@ private:
     void initialize(bool force_pio);
     void detect_disks();
 
-    void start_request(AsyncBlockDeviceRequest&, bool, bool);
-    void complete_current_request(AsyncDeviceRequest::RequestResult);
+    void wait_for_irq();
+    bool ata_read_sectors_with_dma(u32, u16, UserOrKernelBuffer&, bool);
+    bool ata_write_sectors_with_dma(u32, u16, const UserOrKernelBuffer&, bool);
+    bool ata_read_sectors(u32, u16, UserOrKernelBuffer&, bool);
+    bool ata_write_sectors(u32, u16, const UserOrKernelBuffer&, bool);
 
-    void ata_read_sectors_with_dma(bool);
-    void ata_read_sectors(bool);
-    bool ata_do_read_sector();
-    void ata_write_sectors_with_dma(bool);
-    void ata_write_sectors(bool);
-    void ata_do_write_sector();
+    inline void prepare_for_irq();
 
     // Data members
     u8 m_channel_number { 0 }; // Channel number. 0 = master, 1 = slave
@@ -113,10 +108,5 @@ private:
 
     RefPtr<PATADiskDevice> m_master;
     RefPtr<PATADiskDevice> m_slave;
-
-    AsyncBlockDeviceRequest* m_current_request { nullptr };
-    u32 m_current_request_block_index { 0 };
-    bool m_current_request_uses_dma { false };
-    bool m_current_request_flushing_cache { false };
 };
 }
diff --git a/Kernel/Devices/PATADiskDevice.cpp b/Kernel/Devices/PATADiskDevice.cpp
index 8b85783a5b..a81f7bb557 100644
--- a/Kernel/Devices/PATADiskDevice.cpp
+++ b/Kernel/Devices/PATADiskDevice.cpp
@@ -55,10 +55,22 @@ const char* PATADiskDevice::class_name() const
     return "PATADiskDevice";
 }
 
-void PATADiskDevice::start_request(AsyncBlockDeviceRequest& request)
+bool PATADiskDevice::read_blocks(unsigned index, u16 count, UserOrKernelBuffer& out)
 {
-    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());
+    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;
 }
 
 void PATADiskDevice::set_drive_geometry(u16 cyls, u16 heads, u16 spt)
@@ -88,19 +100,8 @@ KResultOr<size_t> PATADiskDevice::read(FileDescription&, size_t offset, UserOrKe
 #endif
 
     if (whole_blocks > 0) {
-        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;
-        }
+        if (!read_blocks(index, whole_blocks, outbuf))
+            return -1;
     }
 
     off_t pos = whole_blocks * block_size();
@@ -108,21 +109,8 @@ 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());
-        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:
+        if (!read_blocks(index + whole_blocks, 1, data_buffer))
             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);
     }
@@ -155,19 +143,8 @@ KResultOr<size_t> PATADiskDevice::write(FileDescription&, size_t offset, const U
 #endif
 
     if (whole_blocks > 0) {
-        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;
-        }
+        if (!write_blocks(index, whole_blocks, inbuf))
+            return -1;
     }
 
     off_t pos = whole_blocks * block_size();
@@ -178,45 +155,12 @@ 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());
-
-        {
-            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 (!read_blocks(index + whole_blocks, 1, data_buffer))
+            return pos;
         if (!inbuf.read(data.data(), pos, remaining))
             return KResult(-EFAULT);
-
-        {
-            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;
-            }
-        }
+        if (!write_blocks(index + whole_blocks, 1, data_buffer))
+            return pos;
     }
 
     return pos + remaining;
@@ -227,6 +171,26 @@ 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;
diff --git a/Kernel/Devices/PATADiskDevice.h b/Kernel/Devices/PATADiskDevice.h
index 1036b06fd5..eb9377e1bf 100644
--- a/Kernel/Devices/PATADiskDevice.h
+++ b/Kernel/Devices/PATADiskDevice.h
@@ -54,10 +54,13 @@ public:
     static NonnullRefPtr<PATADiskDevice> create(PATAChannel&, DriveType, int major, int minor);
     virtual ~PATADiskDevice() override;
 
+    // ^DiskDevice
+    virtual bool read_blocks(unsigned index, u16 count, UserOrKernelBuffer&) override;
+    virtual bool write_blocks(unsigned index, u16 count, const UserOrKernelBuffer&) override;
+
     void set_drive_geometry(u16, u16, u16);
 
     // ^BlockDevice
-    virtual void start_request(AsyncBlockDeviceRequest&) override;
     virtual KResultOr<size_t> read(FileDescription&, size_t, UserOrKernelBuffer&, size_t) override;
     virtual bool can_read(const FileDescription&, size_t) const override;
     virtual KResultOr<size_t> write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t) override;
@@ -70,6 +73,11 @@ private:
     // ^DiskDevice
     virtual const char* class_name() const override;
 
+    bool wait_for_irq();
+    bool read_sectors_with_dma(u32 lba, u16 count, UserOrKernelBuffer&);
+    bool write_sectors_with_dma(u32 lba, u16 count, const UserOrKernelBuffer&);
+    bool read_sectors(u32 lba, u16 count, UserOrKernelBuffer& buffer);
+    bool write_sectors(u32 lba, u16 count, const UserOrKernelBuffer& data);
     bool is_slave() const;
 
     Lock m_lock { "IDEDiskDevice" };