3 files changed, 13 insertions, 17 deletions
diff --git a/include/chardev/char.h b/include/chardev/char.h
index 4181a2784a..7c0444f90d 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -65,6 +65,8 @@ struct Chardev {
     char *filename;
     int logfd;
     int be_open;
+    /* used to coordinate the chardev-change special-case: */
+    bool handover_yank_instance;
     GSource *gsource;
     GMainContext *gcontext;
     DECLARE_BITMAP(features, QEMU_CHAR_FEATURE_LAST);
@@ -251,6 +253,7 @@ struct ChardevClass {
     ObjectClass parent_class;
 
     bool internal; /* TODO: eventually use TYPE_USER_CREATABLE */
+    bool supports_yank;
     void (*parse)(QemuOpts *opts, ChardevBackend *backend, Error **errp);
 
     void (*open)(Chardev *chr, ChardevBackend *backend,
diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index 84eab6e3bf..ce5b9c6851 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -237,11 +237,15 @@ bool qemu_co_enter_next_impl(CoQueue *queue, QemuLockable *lock);
 bool qemu_co_queue_empty(CoQueue *queue);
 
 
+typedef struct CoRwTicket CoRwTicket;
 typedef struct CoRwlock {
-    int pending_writer;
-    int reader;
     CoMutex mutex;
-    CoQueue queue;
+
+    /* Number of readers, or -1 if owned for writing.  */
+    int owners;
+
+    /* Waiting coroutines.  */
+    QSIMPLEQ_HEAD(, CoRwTicket) tickets;
 } CoRwlock;
 
 /**
@@ -260,10 +264,9 @@ void qemu_co_rwlock_rdlock(CoRwlock *lock);
 /**
  * Write Locks the CoRwlock from a reader.  This is a bit more efficient than
  * @qemu_co_rwlock_unlock followed by a separate @qemu_co_rwlock_wrlock.
- * However, if the lock cannot be upgraded immediately, control is transferred
- * to the caller of the current coroutine.  Also, @qemu_co_rwlock_upgrade
- * only overrides CoRwlock fairness if there are no concurrent readers, so
- * another writer might run while @qemu_co_rwlock_upgrade blocks.
+ * Note that if the lock cannot be upgraded immediately, control is transferred
+ * to the caller of the current coroutine; another writer might run while
+ * @qemu_co_rwlock_upgrade blocks.
  */
 void qemu_co_rwlock_upgrade(CoRwlock *lock);
 
diff --git a/include/qemu/yank.h b/include/qemu/yank.h
index 5b93c70cbf..5375a1f195 100644
--- a/include/qemu/yank.h
+++ b/include/qemu/yank.h
@@ -73,16 +73,6 @@ void yank_unregister_function(const YankInstance *instance,
                               YankFn *func,
                               void *opaque);
 
-/**
- * yank_generic_iochannel: Generic yank function for iochannel
- *
- * This is a generic yank function which will call qio_channel_shutdown on the
- * provided QIOChannel.
- *
- * @opaque: QIOChannel to shutdown
- */
-void yank_generic_iochannel(void *opaque);
-
 #define BLOCKDEV_YANK_INSTANCE(the_node_name) (&(YankInstance) { \
         .type = YANK_INSTANCE_TYPE_BLOCK_NODE, \
         .u.block_node.node_name = (the_node_name) })