[PATCH V17 05/13] virtio-vq-mapping: track iothread-vq-mapping references using device path

[Zhang Chen <zhangckid@gmail.com>]

Replace raw object_ref/unref calls with iothread_ref_and_get/
unref_and_put_aio_context in iothread-vq-mapping. This allows
tracking IOThread users via the device's canonical QOM path,
improving lifecycle traceability for virtio-blk and
virtio-scsi devices.

Signed-off-by: Zhang Chen <zhangckid@gmail.com>
---
 hw/block/virtio-blk.c                   |  8 +++++++-
 hw/scsi/virtio-scsi-dataplane.c         |  9 +++++++--
 hw/virtio/iothread-vq-mapping.c         | 20 +++++++++++++++-----
 include/hw/virtio/iothread-vq-mapping.h |  6 +++++-
 4 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 61c341ce2c..b2887d74f9 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -1499,9 +1499,12 @@ static bool virtio_blk_vq_aio_context_init(VirtIOBlock *s, Error **errp)
     s->vq_aio_context = g_new(AioContext *, conf->num_queues);
 
     if (conf->iothread_vq_mapping_list) {
+        g_autofree char *path = object_get_canonical_path(OBJECT(vdev));
+
         if (!iothread_vq_mapping_apply(conf->iothread_vq_mapping_list,
                                        s->vq_aio_context,
                                        conf->num_queues,
+                                       path,
                                        errp)) {
             g_free(s->vq_aio_context);
             s->vq_aio_context = NULL;
@@ -1533,7 +1536,10 @@ static void virtio_blk_vq_aio_context_cleanup(VirtIOBlock *s)
     assert(!s->ioeventfd_started);
 
     if (conf->iothread_vq_mapping_list) {
-        iothread_vq_mapping_cleanup(conf->iothread_vq_mapping_list);
+        g_autofree char *path = object_get_canonical_path(
+                                OBJECT(VIRTIO_DEVICE(s)));
+
+        iothread_vq_mapping_cleanup(conf->iothread_vq_mapping_list, path);
     }
 
     if (conf->iothread) {
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index bcb6e44133..ac13f4a1ca 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -65,9 +65,11 @@ void virtio_scsi_dataplane_setup(VirtIOSCSI *s, Error **errp)
     s->vq_aio_context[1] = qemu_get_aio_context();
 
     if (vs->conf.iothread_vq_mapping_list) {
+        g_autofree char *path = object_get_canonical_path(OBJECT(vdev));
+
         if (!iothread_vq_mapping_apply(vs->conf.iothread_vq_mapping_list,
                     &s->vq_aio_context[VIRTIO_SCSI_VQ_NUM_FIXED],
-                    vs->conf.num_queues, errp)) {
+                    vs->conf.num_queues, path, errp)) {
             g_free(s->vq_aio_context);
             s->vq_aio_context = NULL;
             return;
@@ -94,7 +96,10 @@ void virtio_scsi_dataplane_cleanup(VirtIOSCSI *s)
     VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
 
     if (vs->conf.iothread_vq_mapping_list) {
-        iothread_vq_mapping_cleanup(vs->conf.iothread_vq_mapping_list);
+        g_autofree char *path = object_get_canonical_path(
+                                OBJECT(VIRTIO_DEVICE(s)));
+
+        iothread_vq_mapping_cleanup(vs->conf.iothread_vq_mapping_list, path);
     }
 
     if (vs->conf.iothread) {
diff --git a/hw/virtio/iothread-vq-mapping.c b/hw/virtio/iothread-vq-mapping.c
index 55ce62986c..60e1d55005 100644
--- a/hw/virtio/iothread-vq-mapping.c
+++ b/hw/virtio/iothread-vq-mapping.c
@@ -77,6 +77,7 @@ bool iothread_vq_mapping_apply(
         IOThreadVirtQueueMappingList *list,
         AioContext **vq_aio_context,
         uint16_t num_queues,
+        const char *holder,
         Error **errp)
 {
     IOThreadVirtQueueMappingList *node;
@@ -93,10 +94,13 @@ bool iothread_vq_mapping_apply(
 
     for (node = list; node; node = node->next) {
         IOThread *iothread = iothread_by_id(node->value->iothread);
-        AioContext *ctx = iothread_get_aio_context(iothread);
+        const IOThreadHolder io_holder = {
+            .type = IO_THREAD_HOLDER_KIND_QOM_OBJECT,
+            .u.qom_object.qom_path = (char *)holder,
+        };
 
-        /* Released in virtio_blk_vq_aio_context_cleanup() */
-        object_ref(OBJECT(iothread));
+        AioContext *ctx = iothread_ref_and_get_aio_context(iothread,
+                                                           &io_holder);
 
         if (node->value->vqs) {
             uint16List *vq;
@@ -120,13 +124,19 @@ bool iothread_vq_mapping_apply(
     return true;
 }
 
-void iothread_vq_mapping_cleanup(IOThreadVirtQueueMappingList *list)
+void iothread_vq_mapping_cleanup(IOThreadVirtQueueMappingList *list,
+                                 const char *holder)
 {
     IOThreadVirtQueueMappingList *node;
 
     for (node = list; node; node = node->next) {
         IOThread *iothread = iothread_by_id(node->value->iothread);
-        object_unref(OBJECT(iothread));
+        const IOThreadHolder io_holder = {
+            .type = IO_THREAD_HOLDER_KIND_QOM_OBJECT,
+            .u.qom_object.qom_path = (char *)holder,
+        };
+
+        iothread_unref_and_put_aio_context(iothread, &io_holder);
     }
 }
 
diff --git a/include/hw/virtio/iothread-vq-mapping.h b/include/hw/virtio/iothread-vq-mapping.h
index 57335c3703..0d39caddf3 100644
--- a/include/hw/virtio/iothread-vq-mapping.h
+++ b/include/hw/virtio/iothread-vq-mapping.h
@@ -17,6 +17,7 @@
  * @list: The mapping of virtqueues to IOThreads.
  * @vq_aio_context: The array of AioContext pointers to fill in.
  * @num_queues: The length of @vq_aio_context.
+ * @holder: The QOM paths for attached device.
  * @errp: If an error occurs, a pointer to the area to store the error.
  *
  * Fill in the AioContext for each virtqueue in the @vq_aio_context array given
@@ -31,15 +32,18 @@ bool iothread_vq_mapping_apply(
         IOThreadVirtQueueMappingList *list,
         AioContext **vq_aio_context,
         uint16_t num_queues,
+        const char *holder,
         Error **errp);
 
 /**
  * iothread_vq_mapping_cleanup:
  * @list: The mapping of virtqueues to IOThreads.
+ * @holder: The QOM paths for attached device.
  *
  * Release IOThread object references that were acquired by
  * iothread_vq_mapping_apply().
  */
-void iothread_vq_mapping_cleanup(IOThreadVirtQueueMappingList *list);
+void iothread_vq_mapping_cleanup(IOThreadVirtQueueMappingList *list,
+                                 const char *holder);
 
 #endif /* HW_VIRTIO_IOTHREAD_VQ_MAPPING_H */
-- 
2.43.0