[PATCH V12 04/15] iothread: introduce iothread_unsafe_get_aio_context()

[Zhang Chen <zhangckid@gmail.com>]

Add an explicitly unsafe accessor for legacy callers that cannot
provide a matching holder lifecycle, and convert blockdev.c to use it.

Keep iothread_get_aio_context() temporarily so that later caller
conversions remain independently buildable. It will be removed after
all production callers have migrated.

New code should use iothread_ref_and_get_aio_context().

Signed-off-by: Zhang Chen <zhangckid@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 blockdev.c                |  2 +-
 include/system/iothread.h | 10 ++++++++++
 iothread.c                |  5 +++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/blockdev.c b/blockdev.c
index 6e86c6262f..baeab3a3e1 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3683,7 +3683,7 @@ void qmp_x_blockdev_set_iothread(const char *node_name, StrOrNull *iothread,
             goto out;
         }
 
-        new_context = iothread_get_aio_context(obj);
+        new_context = iothread_unsafe_get_aio_context(obj);
     } else {
         new_context = qemu_get_aio_context();
     }
diff --git a/include/system/iothread.h b/include/system/iothread.h
index f6c5f95dd9..2ef8c1a1bb 100644
--- a/include/system/iothread.h
+++ b/include/system/iothread.h
@@ -68,6 +68,16 @@ char *iothread_get_id(IOThread *iothread);
 IOThread *iothread_by_id(const char *id);
 AioContext *iothread_get_aio_context(IOThread *iothread);
 
+/*
+ * Return @iothread's AioContext without registering a holder or taking a
+ * reference on @iothread.  The caller must ensure that the IOThread remains
+ * alive for as long as the returned AioContext is used.
+ *
+ * This API exists for legacy callers without a clear ref/unref lifecycle.  Do
+ * not use it in new code; use iothread_ref_and_get_aio_context() instead.
+ */
+AioContext *iothread_unsafe_get_aio_context(IOThread *iothread);
+
 /*
  * Register @holder and return @iothread's AioContext.  The holder is copied,
  * and a reference is taken on @iothread so that both the IOThread and its
diff --git a/iothread.c b/iothread.c
index 64be852d1c..3afa296aa0 100644
--- a/iothread.c
+++ b/iothread.c
@@ -443,6 +443,11 @@ void iothread_unref_and_put_aio_context(IOThread *iothread,
     iothread_unref(iothread, holder);
 }
 
+AioContext *iothread_unsafe_get_aio_context(IOThread *iothread)
+{
+    return iothread->ctx;
+}
+
 static int query_one_iothread(Object *object, void *opaque)
 {
     IOThreadInfoList ***tail = opaque;
-- 
2.54.0