[Qemu-devel] [RFC 09/13] main-loop: use thread-local AioContext

[Stefan Hajnoczi <stefanha@redhat.com>]

qemu_bh_new() and several other functions use qemu_aio_context, the
global QEMU main loop AioContext.  Now that we have introduced threads
with their own AioContext and a thread-local AioContext pointer, convert
qemu_bh_new() and friends to use the thread-local AioContext pointer.

qemu_bh_new() now creates a QEMUBH for the current thread's AioContext.
This is the right thing to do - it allows existing code to work outside
the main loop thread.

One exception: qemu_notify_event() still uses the global
qemu_aio_context because all callers expect to kick the main loop, not
some other event loop.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 main-loop.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/main-loop.c b/main-loop.c
index 51eeb0f..2317c54 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -319,7 +319,8 @@ void qemu_del_wait_object(HANDLE handle, WaitObjectFunc *func, void *opaque)
 
 void qemu_fd_register(int fd)
 {
-    WSAEventSelect(fd, event_notifier_get_handle(&qemu_aio_context->notifier),
+    HANDLE h = event_notifier_get_handle(&*get_thread_aio_context()->notifier);
+    WSAEventSelect(fd, h,
                    FD_READ | FD_ACCEPT | FD_CLOSE |
                    FD_CONNECT | FD_WRITE | FD_OOB);
 }
@@ -477,12 +478,12 @@ int main_loop_wait(int nonblocking)
 
 QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
 {
-    return aio_bh_new(qemu_aio_context, cb, opaque);
+    return aio_bh_new(*get_thread_aio_context(), cb, opaque);
 }
 
 bool qemu_aio_wait(void)
 {
-    return aio_poll(qemu_aio_context, true);
+    return aio_poll(*get_thread_aio_context(), true);
 }
 
 #ifdef CONFIG_POSIX
@@ -492,8 +493,8 @@ void qemu_aio_set_fd_handler(int fd,
                              AioFlushHandler *io_flush,
                              void *opaque)
 {
-    aio_set_fd_handler(qemu_aio_context, fd, io_read, io_write, io_flush,
-                       opaque);
+    aio_set_fd_handler(*get_thread_aio_context(), fd,
+                       io_read, io_write, io_flush, opaque);
 }
 #endif
 
@@ -501,5 +502,6 @@ void qemu_aio_set_event_notifier(EventNotifier *notifier,
                                  EventNotifierHandler *io_read,
                                  AioFlushEventNotifierHandler *io_flush)
 {
-    aio_set_event_notifier(qemu_aio_context, notifier, io_read, io_flush);
+    aio_set_event_notifier(*get_thread_aio_context(), notifier,
+                           io_read, io_flush);
 }
-- 
1.8.1.4