winebus.sys: Only keep a single read pending.

dlls/winebus.sys/main.c

@@ -19,6 +19,7 @@
  */
 
 #include <stdarg.h>
+#include <assert.h>
 
 #include "ntstatus.h"
 #define WIN32_NO_STATUS
@@ -74,7 +75,7 @@ struct device_extension
     DWORD last_report_size;
     BOOL last_report_read;
     DWORD buffer_size;
-    LIST_ENTRY irp_queue;
+    IRP *pending_read;
 
     struct unix_device *unix_device;
 };
@@ -249,17 +250,28 @@ static WCHAR *get_compatible_ids(DEVICE_OBJECT *device)
     return dst;
 }
 
+static IRP *pop_pending_read(struct device_extension *ext)
+{
+    IRP *pending;
+
+    RtlEnterCriticalSection(&ext->cs);
+    pending = ext->pending_read;
+    ext->pending_read = NULL;
+    RtlLeaveCriticalSection(&ext->cs);
+
+    return pending;
+}
+
 static void remove_pending_irps(DEVICE_OBJECT *device)
 {
     struct device_extension *ext = device->DeviceExtension;
-    LIST_ENTRY *entry;
+    IRP *pending;
 
-    while ((entry = RemoveHeadList(&ext->irp_queue)) != &ext->irp_queue)
+    if ((pending = pop_pending_read(ext)))
     {
-        IRP *queued_irp = CONTAINING_RECORD(entry, IRP, Tail.Overlay.ListEntry);
-        queued_irp->IoStatus.Status = STATUS_DELETE_PENDING;
-        queued_irp->IoStatus.Information = 0;
-        IoCompleteRequest(queued_irp, IO_NO_INCREMENT);
+        pending->IoStatus.Status = STATUS_DELETE_PENDING;
+        pending->IoStatus.Information = 0;
+        IoCompleteRequest(pending, IO_NO_INCREMENT);
     }
 }
 
@@ -295,7 +307,6 @@ static DEVICE_OBJECT *bus_create_hid_device(struct device_desc *desc, struct uni
     ext->buffer_size        = 0;
     ext->unix_device        = unix_device;
 
-    InitializeListHead(&ext->irp_queue);
     InitializeCriticalSection(&ext->cs);
     ext->cs.DebugInfo->Spare[0] = (DWORD_PTR)(__FILE__ ": cs");
 
@@ -398,9 +409,10 @@ static NTSTATUS deliver_last_report(struct device_extension *ext, DWORD buffer_l
 
 static void process_hid_report(DEVICE_OBJECT *device, BYTE *report, DWORD length)
 {
-    struct device_extension *ext = (struct device_extension*)device->DeviceExtension;
+    struct device_extension *ext = (struct device_extension *)device->DeviceExtension;
+    IO_STACK_LOCATION *stack;
+    ULONG buffer_len;
     IRP *irp;
-    LIST_ENTRY *entry;
 
     if (!length || !report)
         return;
@@ -427,15 +439,11 @@ static void process_hid_report(DEVICE_OBJECT *device, BYTE *report, DWORD length
     ext->last_report_size = length;
     ext->last_report_read = FALSE;
 
-    while ((entry = RemoveHeadList(&ext->irp_queue)) != &ext->irp_queue)
+    if ((irp = pop_pending_read(ext)))
     {
-        IO_STACK_LOCATION *irpsp;
-        TRACE_(hid_report)("Processing Request\n");
-        irp = CONTAINING_RECORD(entry, IRP, Tail.Overlay.ListEntry);
-        irpsp = IoGetCurrentIrpStackLocation(irp);
-        irp->IoStatus.Status = deliver_last_report(ext,
-            irpsp->Parameters.DeviceIoControl.OutputBufferLength,
-            irp->UserBuffer, &irp->IoStatus.Information);
+        stack = IoGetCurrentIrpStackLocation(irp);
+        buffer_len = stack->Parameters.DeviceIoControl.OutputBufferLength;
+        irp->IoStatus.Status = deliver_last_report(ext, buffer_len, irp->UserBuffer, &irp->IoStatus.Information);
         ext->last_report_read = TRUE;
         IoCompleteRequest(irp, IO_NO_INCREMENT);
     }
@@ -1015,7 +1023,10 @@ static NTSTATUS WINAPI hid_internal_dispatch(DEVICE_OBJECT *device, IRP *irp)
             }
             else
             {
-                InsertTailList(&ext->irp_queue, &irp->Tail.Overlay.ListEntry);
+                /* hidclass.sys should guarantee this */
+                assert(!ext->pending_read);
+                ext->pending_read = irp;
+                IoMarkIrpPending(irp);
                 irp->IoStatus.Status = STATUS_PENDING;
             }
             break;