[PATCH V10 14/15] iothread: simplify API by merging iothread_get_aio_context variants

[Zhang Chen <zhangckid@gmail.com>]

Simplify the interface by merging iothread_ref_and_get_aio_context()
into iothread_get_aio_context(). The updated function now requires a
'holder' parameter, ensuring that every retrieval of an AioContext for
long-term use is automatically registered in the IOThread's holder list.

Update all callers across block, virtio, scsi, net, and monitor
subsystems to match the new signature. This cleanup reduces code
redundancy and improves the reliability of IOThread introspection.

Signed-off-by: Zhang Chen <zhangckid@gmail.com>
---
 block/export/export.c           |  5 ++---
 hw/block/dataplane/xen-block.c  |  4 ++--
 hw/block/virtio-blk.c           |  4 ++--
 hw/scsi/virtio-scsi-dataplane.c |  4 ++--
 hw/vfio-user/proxy.c            |  3 +--
 hw/virtio/iothread-vq-mapping.c |  3 +--
 hw/virtio/virtio-balloon.c      |  2 +-
 include/system/iothread.h       | 16 ++++++++--------
 iothread.c                      |  9 ++-------
 monitor/monitor.c               |  2 +-
 net/colo-compare.c              |  2 +-
 11 files changed, 23 insertions(+), 31 deletions(-)

diff --git a/block/export/export.c b/block/export/export.c
index 4dbd71de6a..32c7ef7d28 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -146,7 +146,7 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
             .u.block_export.export_name = (char *)holder_name,
         };
 
-        new_ctx = iothread_ref_and_get_aio_context(iothread, &holder);
+        new_ctx = iothread_get_aio_context(iothread, &holder);
         multithread_count = 1;
         local_iothreads = g_new0(IOThread *, 1);
         local_iothreads[0] = iothread;
@@ -190,8 +190,7 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error **errp)
                 goto fail;
             }
             local_iothreads[i] = iothread;
-            multithread_ctxs[i++] = iothread_ref_and_get_aio_context(iothread,
-                                                                     &holder);
+            multithread_ctxs[i++] = iothread_get_aio_context(iothread, &holder);
         }
         assert(i == multithread_count);
     }
diff --git a/hw/block/dataplane/xen-block.c b/hw/block/dataplane/xen-block.c
index b5bf8d359f..46bfd62f5a 100644
--- a/hw/block/dataplane/xen-block.c
+++ b/hw/block/dataplane/xen-block.c
@@ -628,8 +628,8 @@ XenBlockDataPlane *xen_block_dataplane_create(XenDevice *xendev,
         };
 
         dataplane->iothread = iothread;
-        dataplane->ctx = iothread_ref_and_get_aio_context(dataplane->iothread,
-                                                          &io_holder);
+        dataplane->ctx = iothread_get_aio_context(dataplane->iothread,
+                                                  &io_holder);
     } else {
         dataplane->ctx = qemu_get_aio_context();
     }
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 1865890fad..2c296986ee 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -1508,8 +1508,8 @@ static bool virtio_blk_vq_aio_context_init(VirtIOBlock *s, Error **errp)
             .type = IO_THREAD_HOLDER_KIND_QOM_OBJECT,
             .u.qom_object.qom_path = (char *)path,
         };
-        AioContext *ctx = iothread_ref_and_get_aio_context(conf->iothread,
-                                                           &io_holder);
+        AioContext *ctx = iothread_get_aio_context(conf->iothread,
+                                                   &io_holder);
         for (unsigned i = 0; i < conf->num_queues; i++) {
             s->vq_aio_context[i] = ctx;
         }
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index c71f33b41e..76ab22610f 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -78,8 +78,8 @@ void virtio_scsi_dataplane_setup(VirtIOSCSI *s, Error **errp)
             .type = IO_THREAD_HOLDER_KIND_QOM_OBJECT,
             .u.qom_object.qom_path = (char *)path,
         };
-        AioContext *ctx = iothread_ref_and_get_aio_context(vs->conf.iothread,
-                                                           &io_holder);
+        AioContext *ctx = iothread_get_aio_context(vs->conf.iothread,
+                                                   &io_holder);
         for (uint16_t i = 0; i < vs->conf.num_queues; i++) {
             s->vq_aio_context[VIRTIO_SCSI_VQ_NUM_FIXED + i] = ctx;
         }
diff --git a/hw/vfio-user/proxy.c b/hw/vfio-user/proxy.c
index b4f749f245..8ad0f4cfd3 100644
--- a/hw/vfio-user/proxy.c
+++ b/hw/vfio-user/proxy.c
@@ -942,8 +942,7 @@ VFIOUserProxy *vfio_user_connect_dev(SocketAddress *addr, Error **errp)
         vfio_user_iothread = iothread_create("vfio-user", errp);
     }
 
-    proxy->ctx = iothread_ref_and_get_aio_context(vfio_user_iothread,
-                                                  &io_holder);
+    proxy->ctx = iothread_get_aio_context(vfio_user_iothread, &io_holder);
     proxy->req_bh = qemu_bh_new(vfio_user_request, proxy);
 
     QTAILQ_INIT(&proxy->outgoing);
diff --git a/hw/virtio/iothread-vq-mapping.c b/hw/virtio/iothread-vq-mapping.c
index 2cb48dd387..727358a483 100644
--- a/hw/virtio/iothread-vq-mapping.c
+++ b/hw/virtio/iothread-vq-mapping.c
@@ -99,8 +99,7 @@ bool iothread_vq_mapping_apply(
             .u.qom_object.qom_path = (char *)holder,
         };
 
-        AioContext *ctx = iothread_ref_and_get_aio_context(iothread,
-                                                           &io_holder);
+        AioContext *ctx = iothread_get_aio_context(iothread, &io_holder);
 
         if (node->value->vqs) {
             uint16List *vq;
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index e9d023b4ec..4405a87ed0 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -903,7 +903,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp)
         precopy_add_notifier(&s->free_page_hint_notify);
 
         s->free_page_bh = aio_bh_new_guarded(
-                      iothread_ref_and_get_aio_context(s->iothread, &io_holder),
+                      iothread_get_aio_context(s->iothread, &io_holder),
                       virtio_ballloon_get_free_page_hints, s,
                       &dev->mem_reentrancy_guard);
     }
diff --git a/include/system/iothread.h b/include/system/iothread.h
index 3cce5eeb09..3a6010b9f0 100644
--- a/include/system/iothread.h
+++ b/include/system/iothread.h
@@ -73,22 +73,22 @@ DECLARE_INSTANCE_CHECKER(IOThread, IOTHREAD,
 
 char *iothread_get_id(IOThread *iothread);
 IOThread *iothread_by_id(const char *id);
-/*
- * The iothread_get_aio_context() and iothread_put_aio_context() are not
- * thread-safe and must be called under the Big QEMU Lock (BQL).
- */
-AioContext *iothread_get_aio_context(IOThread *iothread);
+
 /*
  * Normally the IOThread's AioContext is fetched using
- * iothread_ref_and_get_aio_context(), but there are legacy callers
+ * iothread_get_aio_context(), but there are legacy callers
  * without a clear ref/unref lifecycle. They cannot unref (e.g. because
  * they do not have an IOThread pointer), so provide an unsafe way to
  * fetch the AioContext without holding a reference count. This unsafe
  * API serves legacy callers - do not use it in new code.
  */
 AioContext *iothread_unsafe_get_aio_context(IOThread *iothread);
-AioContext *iothread_ref_and_get_aio_context(IOThread *iothread,
-                                             const IOThreadHolder *holder);
+/*
+ * The iothread_get_aio_context() and iothread_put_aio_context() are not
+ * thread-safe and must be called under the Big QEMU Lock (BQL).
+ */
+AioContext *iothread_get_aio_context(IOThread *iothread,
+                                     const IOThreadHolder *holder);
 void iothread_put_aio_context(IOThread *iothread, const IOThreadHolder *holder);
 GMainContext *iothread_get_g_main_context(IOThread *iothread);
 
diff --git a/iothread.c b/iothread.c
index 157bb4d302..9d278efc45 100644
--- a/iothread.c
+++ b/iothread.c
@@ -429,13 +429,8 @@ char *iothread_get_id(IOThread *iothread)
     return g_strdup(object_get_canonical_path_component(OBJECT(iothread)));
 }
 
-AioContext *iothread_get_aio_context(IOThread *iothread)
-{
-    return iothread->ctx;
-}
-
-AioContext *iothread_ref_and_get_aio_context(IOThread *iothread,
-                                             const IOThreadHolder *holder)
+AioContext *iothread_get_aio_context(IOThread *iothread,
+                                     const IOThreadHolder *holder)
 {
     /* Add IOThreadHolder to the list */
     iothread_ref(iothread, holder);
diff --git a/monitor/monitor.c b/monitor/monitor.c
index 688bb85c81..0b75f9f69b 100644
--- a/monitor/monitor.c
+++ b/monitor/monitor.c
@@ -749,7 +749,7 @@ static void monitor_complete(UserCreatable *uc, Error **errp)
             .u.qom_object.qom_path = path,
         };
 
-        mon->ctx = iothread_ref_and_get_aio_context(mon_iothread, &io_holder);
+        mon->ctx = iothread_get_aio_context(mon_iothread, &io_holder);
         ctx = mon->ctx;
     } else {
         ctx = qemu_get_aio_context();
diff --git a/net/colo-compare.c b/net/colo-compare.c
index a7bbb1056d..6cd642d0b7 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -969,7 +969,7 @@ static void colo_compare_iothread(CompareState *s)
         .u.qom_object.qom_path = (char *)path,
     };
 
-    AioContext *ctx = iothread_ref_and_get_aio_context(s->iothread, &io_holder);
+    AioContext *ctx = iothread_get_aio_context(s->iothread, &io_holder);
 
     s->iothread_ctx = ctx;
     s->worker_context = iothread_get_g_main_context(s->iothread);
-- 
2.49.0