Revert "iothread: release iothread around aio_poll"

This reverts commit a0710f7995f914e3044e5899bd8ff6c43c62f916.

In qemu-devel email message <556DBF87.2020908@de.ibm.com>, Christian
Borntraeger writes:

  Having many guests all with a kernel/ramdisk (via -kernel) and
  several null block devices will result in hangs. All hanging
  guests are in partition detection code waiting for an I/O to return
  so very early maybe even the first I/O.

  Reverting that commit "fixes" the hangs.

Reverting this commit for the 2.4 release.  More time is needed to
investigate and correct this patch.

Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/async.c b/async.c
index 46d9e639d7..77d080d6f5 100644
--- a/async.c
+++ b/async.c
@@ -280,6 +280,12 @@ static void aio_timerlist_notify(void *opaque)
     aio_notify(opaque);
 }
 
+static void aio_rfifolock_cb(void *opaque)
+{
+    /* Kick owner thread in case they are blocked in aio_poll() */
+    aio_notify(opaque);
+}
+
 AioContext *aio_context_new(Error **errp)
 {
     int ret;
@@ -297,7 +303,7 @@ AioContext *aio_context_new(Error **errp)
                            event_notifier_test_and_clear);
     ctx->thread_pool = NULL;
     qemu_mutex_init(&ctx->bh_lock);
-    rfifolock_init(&ctx->lock, NULL, NULL);
+    rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);
     timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
 
     return ctx;