migration: simplify blockers

Modify migrate_add_blocker and migrate_del_blocker to take an Error **
reason.  This allows migration to own the Error object, so that if
an error occurs in migrate_add_blocker, migration code can free the Error
and clear the client handle, simplifying client code.  It also simplifies
the migrate_del_blocker call site.

In addition, this is a pre-requisite for a proposed future patch that would
add a mode argument to migration requests to support live update, and
maintain a list of blockers for each mode.  A blocker may apply to a single
mode or to multiple modes, and passing Error** will allow one Error object
to be registered for multiple modes.

No functional change.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Tested-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Michael Galaxy <mgalaxy@akamai.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1697634216-84215-1-git-send-email-steven.sistare@oracle.com>
This commit is contained in:
Steve Sistare 2023-10-18 06:03:36 -07:00 committed by Juan Quintela
parent 04131e0009
commit c8a7fc5179
33 changed files with 92 additions and 150 deletions

View file

@ -332,8 +332,7 @@ static void s390_machine_unprotect(S390CcwMachineState *ms)
s390_pv_vm_disable();
}
ms->pv = false;
migrate_del_blocker(pv_mig_blocker);
error_free_or_abort(&pv_mig_blocker);
migrate_del_blocker(&pv_mig_blocker);
ram_block_discard_disable(false);
}
@ -356,11 +355,10 @@ static int s390_machine_protect(S390CcwMachineState *ms)
error_setg(&pv_mig_blocker,
"protected VMs are currently not migratable.");
rc = migrate_add_blocker(pv_mig_blocker, &local_err);
rc = migrate_add_blocker(&pv_mig_blocker, &local_err);
if (rc) {
ram_block_discard_disable(false);
error_report_err(local_err);
error_free_or_abort(&pv_mig_blocker);
return rc;
}
@ -368,8 +366,7 @@ static int s390_machine_protect(S390CcwMachineState *ms)
rc = s390_pv_vm_enable();
if (rc) {
ram_block_discard_disable(false);
migrate_del_blocker(pv_mig_blocker);
error_free_or_abort(&pv_mig_blocker);
migrate_del_blocker(&pv_mig_blocker);
return rc;
}