Kernel: Allow WorkQueue items allocation failures propagation

In most cases it's safe to abort the requested operation and go forward,
however, in some places it's not clear yet how to handle these failures,
therefore, we use the MUST() wrapper to force a kernel panic for now.

Kernel/Bus/VirtIO/Console.cpp

@@ -151,7 +151,8 @@ void Console::process_control_message(ControlMessage message)
 {
     switch (message.event) {
     case (u16)ControlEvent::DeviceAdd: {
-        g_io_work->queue([message, this]() -> void {
+        // FIXME: Do something sanely here if we can't allocate a work queue?
+        MUST(g_io_work->try_queue([message, this]() -> void {
             u32 id = message.id;
             if (id >= m_ports.size()) {
                 dbgln("Device provided an invalid port number {}. max_nr_ports: {}", id, m_ports.size());
@@ -172,7 +173,7 @@ void Console::process_control_message(ControlMessage message)
                 .value = (u16)ControlMessage::Status::Success
             };
             write_control_message(ready_event);
-        });
+        }));
 
         break;
     }

Kernel/Devices/AsyncDeviceRequest.h

@@ -31,6 +31,7 @@ public:
         Success,
         Failure,
         MemoryFault,
+        OutOfMemory,
         Cancelled
     };
 

Kernel/Devices/HID/PS2KeyboardDevice.cpp

@@ -71,9 +71,10 @@ void PS2KeyboardDevice::irq_handle_byte_read(u8 byte)
         break;
     default:
         if ((m_modifiers & Mod_Alt) != 0 && ch >= 2 && ch <= ConsoleManagement::s_max_virtual_consoles + 1) {
-            g_io_work->queue([ch]() {
+            // FIXME: Do something sanely here if we can't allocate a work queue?
+            MUST(g_io_work->try_queue([ch]() {
                 ConsoleManagement::the().switch_to(ch - 0x02);
-            });
+            }));
         }
         key_state_changed(ch, pressed);
     }

Kernel/Graphics/VirtIOGPU/Console.cpp

@@ -65,10 +65,11 @@ void Console::enqueue_refresh_timer()
                 .width = (u32)rect.width(),
                 .height = (u32)rect.height(),
             };
-            g_io_work->queue([this, dirty_rect]() {
+            // FIXME: Do something sanely here if we can't allocate a work queue?
+            MUST(g_io_work->try_queue([this, dirty_rect]() {
                 m_framebuffer_device->flush_dirty_window(dirty_rect, m_framebuffer_device->current_buffer());
                 m_dirty_rect.clear();
-            });
+            }));
         }
         enqueue_refresh_timer();
     });

Kernel/Storage/ATA/AHCIPort.cpp

@@ -70,13 +70,23 @@ void AHCIPort::handle_interrupt()
         if ((m_port_registers.ssts & 0xf) != 3 && m_connected_device) {
             m_connected_device->prepare_for_unplug();
             StorageManagement::the().remove_device(*m_connected_device);
-            g_io_work->queue([this]() {
+            auto work_item_creation_result = g_io_work->try_queue([this]() {
                 m_connected_device.clear();
             });
+            if (work_item_creation_result.is_error()) {
+                auto current_request = m_current_request;
+                m_current_request.clear();
+                current_request->complete(AsyncDeviceRequest::OutOfMemory);
+            }
         } else {
-            g_io_work->queue([this]() {
+            auto work_item_creation_result = g_io_work->try_queue([this]() {
                 reset();
             });
+            if (work_item_creation_result.is_error()) {
+                auto current_request = m_current_request;
+                m_current_request.clear();
+                current_request->complete(AsyncDeviceRequest::OutOfMemory);
+            }
         }
         return;
     }
@@ -86,15 +96,25 @@ void AHCIPort::handle_interrupt()
     if (m_interrupt_status.is_set(AHCI::PortInterruptFlag::INF)) {
         // We need to defer the reset, because we can receive interrupts when
         // resetting the device.
-        g_io_work->queue([this]() {
+        auto work_item_creation_result = g_io_work->try_queue([this]() {
             reset();
         });
+        if (work_item_creation_result.is_error()) {
+            auto current_request = m_current_request;
+            m_current_request.clear();
+            current_request->complete(AsyncDeviceRequest::OutOfMemory);
+        }
         return;
     }
     if (m_interrupt_status.is_set(AHCI::PortInterruptFlag::IF) || m_interrupt_status.is_set(AHCI::PortInterruptFlag::TFE) || m_interrupt_status.is_set(AHCI::PortInterruptFlag::HBD) || m_interrupt_status.is_set(AHCI::PortInterruptFlag::HBF)) {
-        g_io_work->queue([this]() {
+        auto work_item_creation_result = g_io_work->try_queue([this]() {
             recover_from_fatal_error();
         });
+        if (work_item_creation_result.is_error()) {
+            auto current_request = m_current_request;
+            m_current_request.clear();
+            current_request->complete(AsyncDeviceRequest::OutOfMemory);
+        }
         return;
     }
     if (m_interrupt_status.is_set(AHCI::PortInterruptFlag::DHR) || m_interrupt_status.is_set(AHCI::PortInterruptFlag::PS)) {
@@ -106,7 +126,7 @@ void AHCIPort::handle_interrupt()
         if (!m_current_request) {
             dbgln_if(AHCI_DEBUG, "AHCI Port {}: Request handled, probably identify request", representative_port_index());
         } else {
-            g_io_work->queue([this]() {
+            auto work_item_creation_result = g_io_work->try_queue([this]() {
                 dbgln_if(AHCI_DEBUG, "AHCI Port {}: Request handled", representative_port_index());
                 MutexLocker locker(m_lock);
                 VERIFY(m_current_request);
@@ -128,6 +148,11 @@ void AHCIPort::handle_interrupt()
                 dbgln_if(AHCI_DEBUG, "AHCI Port {}: Request success", representative_port_index());
                 complete_current_request(AsyncDeviceRequest::Success);
             });
+            if (work_item_creation_result.is_error()) {
+                auto current_request = m_current_request;
+                m_current_request.clear();
+                current_request->complete(AsyncDeviceRequest::OutOfMemory);
+            }
         }
     }
 

Kernel/Storage/ATA/BMIDEChannel.cpp

@@ -121,7 +121,7 @@ void BMIDEChannel::complete_current_request(AsyncDeviceRequest::RequestResult re
     // 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!
-    g_io_work->queue([this, result]() {
+    auto work_item_creation_result = g_io_work->try_queue([this, result]() {
         dbgln_if(PATA_DEBUG, "BMIDEChannel::complete_current_request result: {}", (int)result);
         SpinlockLocker lock(m_request_lock);
         VERIFY(m_current_request);
@@ -145,6 +145,11 @@ void BMIDEChannel::complete_current_request(AsyncDeviceRequest::RequestResult re
         lock.unlock();
         current_request->complete(result);
     });
+    if (work_item_creation_result.is_error()) {
+        auto current_request = m_current_request;
+        m_current_request.clear();
+        current_request->complete(AsyncDeviceRequest::OutOfMemory);
+    }
 }
 
 void BMIDEChannel::ata_write_sectors(bool slave_request, u16 capabilities)

Kernel/Storage/ATA/IDEChannel.cpp

@@ -129,7 +129,7 @@ void IDEChannel::complete_current_request(AsyncDeviceRequest::RequestResult resu
     // 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!
-    g_io_work->queue([this, result]() {
+    auto work_item_creation_result = g_io_work->try_queue([this, result]() {
         dbgln_if(PATA_DEBUG, "IDEChannel::complete_current_request result: {}", (int)result);
         MutexLocker locker(m_lock);
         VERIFY(m_current_request);
@@ -137,6 +137,11 @@ void IDEChannel::complete_current_request(AsyncDeviceRequest::RequestResult resu
         m_current_request.clear();
         current_request->complete(result);
     });
+    if (work_item_creation_result.is_error()) {
+        auto current_request = m_current_request;
+        m_current_request.clear();
+        current_request->complete(AsyncDeviceRequest::OutOfMemory);
+    }
 }
 
 static void print_ide_status(u8 status)
@@ -218,7 +223,7 @@ bool IDEChannel::handle_irq(RegisterState const&)
     // 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
-    g_io_work->queue([this]() {
+    auto work_item_creation_result = g_io_work->try_queue([this]() {
         MutexLocker locker(m_lock);
         SpinlockLocker lock(m_request_lock);
         if (m_current_request->request_type() == AsyncBlockDeviceRequest::Read) {
@@ -249,6 +254,11 @@ bool IDEChannel::handle_irq(RegisterState const&)
             }
         }
     });
+    if (work_item_creation_result.is_error()) {
+        auto current_request = m_current_request;
+        m_current_request.clear();
+        current_request->complete(AsyncDeviceRequest::OutOfMemory);
+    }
     return true;
 }
 

Kernel/Storage/NVMe/NVMeInterruptQueue.cpp

@@ -33,7 +33,7 @@ void NVMeInterruptQueue::complete_current_request(u16 status)
 {
     VERIFY(m_request_lock.is_locked());
 
-    g_io_work->queue([this, status]() {
+    auto work_item_creation_result = g_io_work->try_queue([this, status]() {
         SpinlockLocker lock(m_request_lock);
         auto current_request = m_current_request;
         m_current_request.clear();
@@ -53,5 +53,10 @@ void NVMeInterruptQueue::complete_current_request(u16 status)
         current_request->complete(AsyncDeviceRequest::Success);
         return;
     });
+    if (work_item_creation_result.is_error()) {
+        auto current_request = m_current_request;
+        m_current_request.clear();
+        current_request->complete(AsyncDeviceRequest::OutOfMemory);
+    }
 }
 }

Kernel/WorkQueue.h

@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <AK/Error.h>
 #include <AK/IntrusiveList.h>
 #include <Kernel/Forward.h>
 #include <Kernel/Locking/SpinlockProtected.h>
@@ -23,23 +24,29 @@ class WorkQueue {
 public:
     static void initialize();
 
-    void queue(void (*function)(void*), void* data = nullptr, void (*free_data)(void*) = nullptr)
+    ErrorOr<void> try_queue(void (*function)(void*), void* data = nullptr, void (*free_data)(void*) = nullptr)
     {
-        auto* item = new WorkItem; // TODO: use a pool
+        auto item = new (nothrow) WorkItem; // TODO: use a pool
+        if (!item)
+            return Error::from_errno(ENOMEM);
         item->function = [function, data, free_data] {
             function(data);
             if (free_data)
                 free_data(data);
         };
         do_queue(item);
+        return {};
     }
 
     template<typename Function>
-    void queue(Function function)
+    ErrorOr<void> try_queue(Function function)
     {
-        auto* item = new WorkItem; // TODO: use a pool
+        auto item = new (nothrow) WorkItem; // TODO: use a pool
+        if (!item)
+            return Error::from_errno(ENOMEM);
         item->function = Function(function);
         do_queue(item);
+        return {};
     }
 
 private: