[PATCH 2/3] migration: Simplify calling of await_return_path_close_on_source

[Fabiano Rosas <farosas@suse.de>]

We're about to reuse this function so move the 'rp_thread_created'
check into it and remove the redundant tracing and comment.

Add a new tracepoint akin to what is already done at
migration_completion().

Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 migration/migration.c  | 21 +++++++--------------
 migration/trace-events |  3 +--
 2 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 051067f8c5..d6f4470265 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2038,6 +2038,10 @@ static int open_return_path_on_source(MigrationState *ms,
 /* Returns 0 if the RP was ok, otherwise there was an error on the RP */
 static int await_return_path_close_on_source(MigrationState *ms)
 {
+    if (!ms->rp_state.rp_thread_created) {
+        return 0;
+    }
+
     /*
      * If this is a normal exit then the destination will send a SHUT and the
      * rp_thread will exit, however if there's an error we need to cause
@@ -2350,20 +2354,9 @@ static void migration_completion(MigrationState *s)
         goto fail;
     }
 
-    /*
-     * If rp was opened we must clean up the thread before
-     * cleaning everything else up (since if there are no failures
-     * it will wait for the destination to send it's status in
-     * a SHUT command).
-     */
-    if (s->rp_state.rp_thread_created) {
-        int rp_error;
-        trace_migration_return_path_end_before();
-        rp_error = await_return_path_close_on_source(s);
-        trace_migration_return_path_end_after(rp_error);
-        if (rp_error) {
-            goto fail;
-        }
+    if (await_return_path_close_on_source(s)) {
+        trace_migration_completion_rp_err();
+        goto fail;
     }
 
     if (qemu_file_get_error(s->to_dst_file)) {
diff --git a/migration/trace-events b/migration/trace-events
index 5259c1044b..33a69064ca 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -157,13 +157,12 @@ migrate_pending_estimate(uint64_t size, uint64_t pre, uint64_t post) "estimate p
 migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
 migrate_send_rp_recv_bitmap(char *name, int64_t size) "block '%s' size 0x%"PRIi64
 migration_completion_file_err(void) ""
+migration_completion_rp_err(void) ""
 migration_completion_vm_stop(int ret) "ret %d"
 migration_completion_postcopy_end(void) ""
 migration_completion_postcopy_end_after_complete(void) ""
 migration_rate_limit_pre(int ms) "%d ms"
 migration_rate_limit_post(int urgent) "urgent: %d"
-migration_return_path_end_before(void) ""
-migration_return_path_end_after(int rp_error) "%d"
 migration_thread_after_loop(void) ""
 migration_thread_file_err(void) ""
 migration_thread_setup_complete(void) ""
-- 
2.35.3