block/raw-win32: create one QEMUWin32AIOState per BDRVRawState

Each QEMUWin32AIOState event notifier is associated with an AioContext.
Since BlockDriverState instances can use different AioContexts we cannot
continue to use a global QEMUWin32AIOState.

Let each BDRVRawState have its own QEMUWin32AIOState and free it when
BDRVRawState is closed.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block/raw-aio.h

@@ -45,6 +45,7 @@ void laio_attach_aio_context(void *s, AioContext *new_context);
 #ifdef _WIN32
 typedef struct QEMUWin32AIOState QEMUWin32AIOState;
 QEMUWin32AIOState *win32_aio_init(void);
+void win32_aio_cleanup(QEMUWin32AIOState *aio);
 int win32_aio_attach(QEMUWin32AIOState *aio, HANDLE hfile);
 BlockDriverAIOCB *win32_aio_submit(BlockDriverState *bs,
         QEMUWin32AIOState *aio, HANDLE hfile,

block/raw-win32.c

@@ -36,8 +36,6 @@
 #define FTYPE_CD     1
 #define FTYPE_HARDDISK 2
 
-static QEMUWin32AIOState *aio;
-
 typedef struct RawWin32AIOData {
     BlockDriverState *bs;
     HANDLE hfile;
@@ -300,15 +298,6 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
 
     raw_parse_flags(flags, &access_flags, &overlapped);
 
-    if ((flags & BDRV_O_NATIVE_AIO) && aio == NULL) {
-        aio = win32_aio_init();
-        if (aio == NULL) {
-            error_setg(errp, "Could not initialize AIO");
-            ret = -EINVAL;
-            goto fail;
-        }
-    }
-
     if (filename[0] && filename[1] == ':') {
         snprintf(s->drive_path, sizeof(s->drive_path), "%c:\\", filename[0]);
     } else if (filename[0] == '\\' && filename[1] == '\\') {
@@ -335,13 +324,21 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     if (flags & BDRV_O_NATIVE_AIO) {
-        ret = win32_aio_attach(aio, s->hfile);
+        s->aio = win32_aio_init();
+        if (s->aio == NULL) {
+            CloseHandle(s->hfile);
+            error_setg(errp, "Could not initialize AIO");
+            ret = -EINVAL;
+            goto fail;
+        }
+
+        ret = win32_aio_attach(s->aio, s->hfile);
         if (ret < 0) {
+            win32_aio_cleanup(s->aio);
             CloseHandle(s->hfile);
             error_setg_errno(errp, -ret, "Could not enable AIO");
             goto fail;
         }
-        s->aio = aio;
     }
 
     raw_probe_alignment(bs);
@@ -389,6 +386,12 @@ static BlockDriverAIOCB *raw_aio_flush(BlockDriverState *bs,
 static void raw_close(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
+
+    if (s->aio) {
+        win32_aio_cleanup(s->aio);
+        s->aio = NULL;
+    }
+
     CloseHandle(s->hfile);
     if (bs->open_flags & BDRV_O_TEMPORARY) {
         unlink(bs->filename);

block/win32-aio.c

@@ -204,3 +204,11 @@ QEMUWin32AIOState *win32_aio_init(void)
     g_free(s);
     return NULL;
 }
+
+void win32_aio_cleanup(QEMUWin32AIOState *aio)
+{
+    qemu_aio_set_event_notifier(&aio->e, NULL);
+    CloseHandle(aio->hIOCP);
+    event_notifier_cleanup(&aio->e);
+    g_free(aio);
+}