aio-posix: make AioHandler deletion O(1)

It is not necessary to scan all AioHandlers for deletion.  Keep a list
of deleted handlers instead of scanning the full list of all handlers.

The AioHandler->deleted field can be dropped.  Let's check if the
handler has been inserted into the deleted list instead.  Add a new
QLIST_IS_INSERTED() API for this check.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Sergio Lopez <slp@redhat.com>
Message-id: 20200214171712.541358-5-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/include/block/aio.h b/include/block/aio.h
index 1a2ce9ca26..9dd61cee7e 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -42,6 +42,7 @@ void qemu_aio_unref(void *p);
 void qemu_aio_ref(void *p);
 
 typedef struct AioHandler AioHandler;
+typedef QLIST_HEAD(, AioHandler) AioHandlerList;
 typedef void QEMUBHFunc(void *opaque);
 typedef bool AioPollFn(void *opaque);
 typedef void IOHandler(void *opaque);
@@ -71,7 +72,10 @@ struct AioContext {
     QemuRecMutex lock;
 
     /* The list of registered AIO handlers.  Protected by ctx->list_lock. */
-    QLIST_HEAD(, AioHandler) aio_handlers;
+    AioHandlerList aio_handlers;
+
+    /* The list of AIO handlers to be deleted.  Protected by ctx->list_lock. */
+    AioHandlerList deleted_aio_handlers;
 
     /* Used to avoid unnecessary event_notifier_set calls in aio_notify;
      * accessed with atomic primitives.  If this field is 0, everything