migration: Refactor migration_incoming_setup()

Commit 6720c2b32725 ("migration: check magic value for deciding the
mapping of channels") extracted the only code that could fail in
migration_incoming_setup().

Now migration_incoming_setup() can't fail, so refactor it to return void
and remove errp parameter.

Signed-off-by: Avihai Horon <avihaih@nvidia.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lore.kernel.org/r/20231231093016.14204-4-avihaih@nvidia.com
Signed-off-by: Peter Xu <peterx@redhat.com>
diff --git a/migration/migration.c b/migration/migration.c
index 15dc8aa..e7d342a 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -724,11 +724,8 @@
 /**
  * migration_incoming_setup: Setup incoming migration
  * @f: file for main migration channel
- * @errp: where to put errors
- *
- * Returns: %true on success, %false on error.
  */
-static bool migration_incoming_setup(QEMUFile *f, Error **errp)
+static void migration_incoming_setup(QEMUFile *f)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
 
@@ -736,7 +733,6 @@
         mis->from_src_file = f;
     }
     qemu_file_set_blocking(f, false);
-    return true;
 }
 
 void migration_incoming_process(void)
@@ -780,9 +776,7 @@
 
 void migration_fd_process_incoming(QEMUFile *f, Error **errp)
 {
-    if (!migration_incoming_setup(f, errp)) {
-        return;
-    }
+    migration_incoming_setup(f);
     if (postcopy_try_recover()) {
         return;
     }
@@ -855,10 +849,7 @@
 
     if (default_channel) {
         f = qemu_file_new_input(ioc);
-
-        if (!migration_incoming_setup(f, errp)) {
-            return;
-        }
+        migration_incoming_setup(f);
     } else {
         /* Multiple connections */
         assert(migration_needs_multiple_sockets());