migration: Move CPR HUP watch to cpr-transfer.c

Move this CPR-specific code into a cpr file. While here, give the
functions more significant names.

This makes the new idea (after cpr-transfer) of having two parts to
qmp_migrate slightly more obvious: either wait for the hangup or
continue directly.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Prasad Pandit <pjp@fedoraproject.org>
Link: https://lore.kernel.org/qemu-devel/20260123141656.6765-24-farosas@suse.de
Signed-off-by: Fabiano Rosas <farosas@suse.de>

include/migration/cpr.h

@@ -9,6 +9,7 @@
 #define MIGRATION_CPR_H
 
 #include "qapi/qapi-types-migration.h"
+#include "io/channel.h"
 #include "qemu/queue.h"
 
 #define MIG_MODE_NONE           -1
@@ -53,6 +54,10 @@ int cpr_get_fd_param(const char *name, const char *fdname, int index,
 QEMUFile *cpr_transfer_output(MigrationChannel *channel, Error **errp);
 QEMUFile *cpr_transfer_input(MigrationChannel *channel, Error **errp);
 
+void cpr_transfer_add_hup_watch(MigrationState *s, QIOChannelFunc func,
+                                void *opaque);
+void cpr_transfer_source_destroy(MigrationState *s);
+
 void cpr_exec_init(void);
 QEMUFile *cpr_exec_output(Error **errp);
 QEMUFile *cpr_exec_input(Error **errp);

migration/cpr-transfer.c

@@ -6,7 +6,10 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/clone-visitor.h"
 #include "qapi/error.h"
+#include "qapi/qapi-visit-migration.h"
+#include "io/channel.h"
 #include "io/channel-file.h"
 #include "io/channel-socket.h"
 #include "io/net-listener.h"
@@ -72,3 +75,23 @@ QEMUFile *cpr_transfer_input(MigrationChannel *channel, Error **errp)
         return NULL;
     }
 }
+
+void cpr_transfer_add_hup_watch(MigrationState *s, QIOChannelFunc func,
+                                void *opaque)
+{
+    s->hup_source = qio_channel_create_watch(cpr_state_ioc(), G_IO_HUP);
+    g_source_set_callback(s->hup_source,
+                          (GSourceFunc)func,
+                          QAPI_CLONE(MigrationAddress, opaque),
+                          (GDestroyNotify)qapi_free_MigrationAddress);
+    g_source_attach(s->hup_source, NULL);
+}
+
+void cpr_transfer_source_destroy(MigrationState *s)
+{
+    if (s->hup_source) {
+        g_source_destroy(s->hup_source);
+        g_source_unref(s->hup_source);
+        s->hup_source = NULL;
+    }
+}

migration/migration.c

@@ -99,7 +99,6 @@ static bool migration_object_check(MigrationState *ms, Error **errp);
 static bool migration_switchover_start(MigrationState *s, Error **errp);
 static bool close_return_path_on_source(MigrationState *s);
 static void migration_completion_end(MigrationState *s);
-static void migrate_hup_delete(MigrationState *s);
 
 static void migration_downtime_start(MigrationState *s)
 {
@@ -1296,7 +1295,7 @@ static void migration_cleanup(MigrationState *s)
 
     qemu_savevm_state_cleanup();
     cpr_state_close();
-    migrate_hup_delete(s);
+    cpr_transfer_source_destroy(s);
 
     close_return_path_on_source(s);
 
@@ -1477,7 +1476,7 @@ void migration_cancel(void)
         migrate_set_state(&s->state, MIGRATION_STATUS_CANCELLING,
                           MIGRATION_STATUS_CANCELLED);
         cpr_state_close();
-        migrate_hup_delete(s);
+        cpr_transfer_source_destroy(s);
     }
 }
 
@@ -2001,25 +2000,6 @@ static bool migrate_prepare(MigrationState *s, bool resume, Error **errp)
 
 static void qmp_migrate_finish(MigrationAddress *addr, Error **errp);
 
-static void migrate_hup_add(MigrationState *s, QIOChannel *ioc, GSourceFunc cb,
-                            void *opaque)
-{
-    s->hup_source = qio_channel_create_watch(ioc, G_IO_HUP);
-    g_source_set_callback(s->hup_source, cb,
-                          QAPI_CLONE(MigrationAddress, opaque),
-                          (GDestroyNotify)qapi_free_MigrationAddress);
-    g_source_attach(s->hup_source, NULL);
-}
-
-static void migrate_hup_delete(MigrationState *s)
-{
-    if (s->hup_source) {
-        g_source_destroy(s->hup_source);
-        g_source_unref(s->hup_source);
-        s->hup_source = NULL;
-    }
-}
-
 static gboolean qmp_migrate_finish_cb(QIOChannel *channel,
                                       GIOCondition cond,
                                       void *opaque)
@@ -2075,8 +2055,7 @@ void qmp_migrate(const char *uri, bool has_channels,
      * connection, so qmp_migrate_finish will fail to connect, and then recover.
      */
     if (migrate_mode() == MIG_MODE_CPR_TRANSFER) {
-        migrate_hup_add(s, cpr_state_ioc(), (GSourceFunc)qmp_migrate_finish_cb,
-                        main_ch->addr);
+        cpr_transfer_add_hup_watch(s, qmp_migrate_finish_cb, main_ch->addr);
 
     } else {
         qmp_migrate_finish(main_ch->addr, errp);