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

@ -903,8 +903,7 @@ static void ivshmem_common_realize(PCIDevice *dev, Error **errp)
if (!ivshmem_is_master(s)) {
error_setg(&s->migration_blocker,
"Migration is disabled when using feature 'peer mode' in device 'ivshmem'");
if (migrate_add_blocker(s->migration_blocker, errp) < 0) {
error_free(s->migration_blocker);
if (migrate_add_blocker(&s->migration_blocker, errp) < 0) {
return;
}
}
@ -922,10 +921,7 @@ static void ivshmem_exit(PCIDevice *dev)
IVShmemState *s = IVSHMEM_COMMON(dev);
int i;
if (s->migration_blocker) {
migrate_del_blocker(s->migration_blocker);
error_free(s->migration_blocker);
}
migrate_del_blocker(&s->migration_blocker);
if (memory_region_is_mapped(s->ivshmem_bar2)) {
if (!s->hostmem) {