Re: [PATCH v6 4/5] migration: process_incoming_migration_co(): rework error reporting

[Vladimir Sementsov-Ogievskiy]

On 30.04.24 12:16, Philippe Mathieu-Daudé wrote:
> On 30/4/24 10:56, Vladimir Sementsov-Ogievskiy wrote:
> > Unify error reporting in the function. This simplifies the following
> > commit, which will not-exit-on-error behavior variant to the function.
> >
> > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
> > ---
> >   migration/migration.c | 23 +++++++++++++----------
> >   1 file changed, 13 insertions(+), 10 deletions(-)
> >
> > diff --git a/migration/migration.c b/migration/migration.c
> > index b307a4bc59..a9599838e6 100644
> > --- a/migration/migration.c
> > +++ b/migration/migration.c
> > @@ -735,14 +735,16 @@ static void process_incoming_migration_bh(void *opaque)
> >   static void coroutine_fn
> >   process_incoming_migration_co(void *opaque)
> >   {
> > +    MigrationState *s = migrate_get_current();
>
> (see below)
>
> >       MigrationIncomingState *mis = migration_incoming_get_current();
> >       PostcopyState ps;
> >       int ret;
> > +    Error *local_err = NULL;
> >       assert(mis->from_src_file);
> >       if (compress_threads_load_setup(mis->from_src_file)) {
> > -        error_report("Failed to setup decompress threads");
> > +        error_setg(&local_err, "Failed to setup decompress threads");
> >           goto fail;
> >       }
> > @@ -779,19 +781,12 @@ process_incoming_migration_co(void *opaque)
> >       }
> >       if (ret < 0) {
> > -        MigrationState *s = migrate_get_current();
> > -
> > -        if (migrate_has_error(s)) {
> > -            WITH_QEMU_LOCK_GUARD(&s->error_mutex) {
> > -                error_report_err(s->error);
> > -                s->error = NULL;
> > -            }
> > -        }
> > -        error_report("load of migration failed: %s", strerror(-ret));
> > +        error_setg(&local_err, "load of migration failed: %s", strerror(-ret));
> >           goto fail;
> >       }
> >       if (colo_incoming_co() < 0) {
> > +        error_setg(&local_err, "colo incoming failed");
> >           goto fail;
> >       }
> > @@ -800,8 +795,16 @@ process_incoming_migration_co(void *opaque)
> >   fail:
>
> Maybe just assign @s in error path here?
>
>         s = migrate_get_current();

I'd keep as is. If continue improving the function, I'd better split the logic to 
seperate function with classic "Error **errp" argument. And keep reporting 
error in caller.

> >       migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
> >                         MIGRATION_STATUS_FAILED);
> > +    migrate_set_error(s, local_err);
> > +    error_free(local_err);
> > +
> >       migration_incoming_state_destroy();
> > +    WITH_QEMU_LOCK_GUARD(&s->error_mutex) {
> > +        error_report_err(s->error);
> > +        s->error = NULL;
> > +    }
> > +
> >       exit(EXIT_FAILURE);
> >   }
>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

--
Best regards,
Vladimir