aio: remove aio_disable_external() API

All callers now pass is_external=false to aio_set_fd_handler() and
aio_set_event_notifier(). The aio_disable_external() API that
temporarily disables fd handlers that were registered is_external=true
is therefore dead code.

Remove aio_disable_external(), aio_enable_external(), and the
is_external arguments to aio_set_fd_handler() and
aio_set_event_notifier().

The entire test-fdmon-epoll test is removed because its sole purpose was
testing aio_disable_external().

Parts of this patch were generated using the following coccinelle
(https://coccinelle.lip6.fr/) semantic patch:

  @@
  expression ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque;
  @@
  - aio_set_fd_handler(ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque)
  + aio_set_fd_handler(ctx, fd, io_read, io_write, io_poll, io_poll_ready, opaque)

  @@
  expression ctx, notifier, is_external, io_read, io_poll, io_poll_ready;
  @@
  - aio_set_event_notifier(ctx, notifier, is_external, io_read, io_poll, io_poll_ready)
  + aio_set_event_notifier(ctx, notifier, io_read, io_poll, io_poll_ready)

Reviewed-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230516190238.8401-21-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/io_uring.c b/block/io_uring.c
index 82cab6a..3a77480 100644
--- a/block/io_uring.c
+++ b/block/io_uring.c
@@ -410,7 +410,7 @@
 
 void luring_detach_aio_context(LuringState *s, AioContext *old_context)
 {
-    aio_set_fd_handler(old_context, s->ring.ring_fd, false,
+    aio_set_fd_handler(old_context, s->ring.ring_fd,
                        NULL, NULL, NULL, NULL, s);
     qemu_bh_delete(s->completion_bh);
     s->aio_context = NULL;
@@ -420,7 +420,7 @@
 {
     s->aio_context = new_context;
     s->completion_bh = aio_bh_new(new_context, qemu_luring_completion_bh, s);
-    aio_set_fd_handler(s->aio_context, s->ring.ring_fd, false,
+    aio_set_fd_handler(s->aio_context, s->ring.ring_fd,
                        qemu_luring_completion_cb, NULL,
                        qemu_luring_poll_cb, qemu_luring_poll_ready, s);
 }