block: remove AioContext locking

This is the big patch that removes
aio_context_acquire()/aio_context_release() from the block layer and
affected block layer users.

There isn't a clean way to split this patch and the reviewers are likely
the same group of people, so I decided to do it in one patch.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Message-ID: <20231205182011.1976568-7-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

2 files changed, 0 insertions, 7 deletions

diff --git a/util/async.c b/util/async.c
index 04ee83d..dfd44ef 100644
--- a/util/async.c
+++ b/util/async.c
@@ -562,12 +562,10 @@ static void co_schedule_bh_cb(void *opaque)
         Coroutine *co = QSLIST_FIRST(&straight);
         QSLIST_REMOVE_HEAD(&straight, co_scheduled_next);
         trace_aio_co_schedule_bh_cb(ctx, co);
-        aio_context_acquire(ctx);
 
         /* Protected by write barrier in qemu_aio_coroutine_enter */
         qatomic_set(&co->scheduled, NULL);
         qemu_aio_coroutine_enter(ctx, co);
-        aio_context_release(ctx);
     }
 }
 
@@ -707,9 +705,7 @@ void aio_co_enter(AioContext *ctx, Coroutine *co)
         assert(self != co);
         QSIMPLEQ_INSERT_TAIL(&self->co_queue_wakeup, co, co_queue_next);
     } else {
-        aio_context_acquire(ctx);
         qemu_aio_coroutine_enter(ctx, co);
-        aio_context_release(ctx);
     }
 }
 
diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index a9a48ff..3bfb1ad 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -360,10 +360,7 @@ static void vu_accept(QIONetListener *listener, QIOChannelSocket *sioc,
 
     qio_channel_set_follow_coroutine_ctx(server->ioc, true);
 
-    /* Attaching the AioContext starts the vu_client_trip coroutine */
-    aio_context_acquire(server->ctx);
     vhost_user_server_attach_aio_context(server, server->ctx);
-    aio_context_release(server->ctx);
 }
 
 /* server->ctx acquired by caller */