Kernel/USB: Use allocate_kernel_region in Transfer buffer allocations

Previously it would create a contiguous AVMO manually and pass it to
MM. This uses supervisor pages that quickly run out as they never get
returned and crash the system.

Instead, use allocate_kernel_region as we're only allocating a page so
it will be contiguous and will be returned when destroyed.

A potentially better solution would be to use a pool of transfers to
avoid all the allocations. This just prevents the system from crashing
within ~5 seconds from the continuous hub polling.

2 files changed, 15 insertions, 15 deletions

diff --git a/Kernel/Bus/USB/USBTransfer.cpp b/Kernel/Bus/USB/USBTransfer.cpp
index 82fb695e76..09a0959efb 100644
--- a/Kernel/Bus/USB/USBTransfer.cpp
+++ b/Kernel/Bus/USB/USBTransfer.cpp
@@ -11,20 +11,20 @@ namespace Kernel::USB {
 
 RefPtr<Transfer> Transfer::try_create(Pipe& pipe, u16 len)
 {
-    auto vmobject = Memory::AnonymousVMObject::try_create_physically_contiguous_with_size(PAGE_SIZE);
-    if (!vmobject)
-        return nullptr;
+    // Initialize data buffer for transfer
+    // This will definitely need to be refactored in the future, I doubt this will scale well...
+    auto data_buffer = MM.allocate_kernel_region(PAGE_SIZE, "USB Transfer Buffer", Memory::Region::Access::ReadWrite);
+    if (!data_buffer)
+        return {};
 
-    return AK::try_create<Transfer>(pipe, len, *vmobject);
+    return AK::try_create<Transfer>(pipe, len, data_buffer.release_nonnull());
 }
 
-Transfer::Transfer(Pipe& pipe, u16 len, Memory::AnonymousVMObject& vmobject)
+Transfer::Transfer(Pipe& pipe, u16 len, NonnullOwnPtr<Memory::Region> data_buffer)
     : m_pipe(pipe)
+    , m_data_buffer(move(data_buffer))
     , m_transfer_data_size(len)
 {
-    // Initialize data buffer for transfer
-    // This will definitely need to be refactored in the future, I doubt this will scale well...
-    m_data_buffer = MM.allocate_kernel_region_with_vmobject(vmobject, PAGE_SIZE, "USB Transfer Buffer", Memory::Region::Access::ReadWrite);
 }
 
 Transfer::~Transfer()
diff --git a/Kernel/Bus/USB/USBTransfer.h b/Kernel/Bus/USB/USBTransfer.h
index 9afead95e9..298bb38af7 100644
--- a/Kernel/Bus/USB/USBTransfer.h
+++ b/Kernel/Bus/USB/USBTransfer.h
@@ -23,7 +23,7 @@ public:
 
 public:
     Transfer() = delete;
-    Transfer(Pipe& pipe, u16 len, Memory::AnonymousVMObject&);
+    Transfer(Pipe& pipe, u16 len, NonnullOwnPtr<Memory::Region>);
     ~Transfer();
 
     void set_setup_packet(const USBRequestData& request);
@@ -41,11 +41,11 @@ public:
     bool error_occurred() const { return m_error_occurred; }
 
 private:
-    Pipe& m_pipe;                         // Pipe that initiated this transfer
-    USBRequestData m_request;             // USB request
-    OwnPtr<Memory::Region> m_data_buffer; // DMA Data buffer for transaction
-    u16 m_transfer_data_size { 0 };       // Size of the transfer's data stage
-    bool m_complete { false };            // Has this transfer been completed?
-    bool m_error_occurred { false };      // Did an error occur during this transfer?
+    Pipe& m_pipe;                                // Pipe that initiated this transfer
+    USBRequestData m_request;                    // USB request
+    NonnullOwnPtr<Memory::Region> m_data_buffer; // DMA Data buffer for transaction
+    u16 m_transfer_data_size { 0 };              // Size of the transfer's data stage
+    bool m_complete { false };                   // Has this transfer been completed?
+    bool m_error_occurred { false };             // Did an error occur during this transfer?
 };
 }