Peter Xu <[email protected]> writes:
> On Fri, Dec 26, 2025 at 06:19:15PM -0300, Fabiano Rosas wrote:
>> Simplify migration_channel_connect() and migration_connect() to not
>> take an error as input. Move the error handling into the paths that
>> generate the error.
>>
>> To achive this, call migration_connect_error_propagate() from socket.c
>> and tls.c, which are the async paths.
>>
>> For the sync paths, the handling is done as normal by returning all
>> the way to qmp_migrate_finish(), except that now the sync paths don't
>> pass the error forward into migration_connect() anymore.
>>
>> Signed-off-by: Fabiano Rosas <[email protected]>
>
> Yeah this looks better in general, feel free to take:
>
> Reviewed-by: Peter Xu <[email protected]>
>
> One thing to mention:
>
> Strictly speaking, migration_tls_channel_connect() doesn't fall into the
> "async op" category - it was invoked from migration core, so logically it
> can still keep its errp, then the migration core should also be able to
> process the error in migration_channel_connect(). It's not like the other
> two "async ops" where migration context was lost.
>
I actually had it return the error in a previous version. Let me check
if it still makes sense to do that.
> IOW, I can kind of see why we used to pass an Error into the current
> migration_channel_connect(), and it still makes some sense.
Yes, it was definitely not incorrect. I just think it's become a
surprising thing to do given how the code has evolved.
> OTOH, it doesn't really make sense to me to keep passing it to
> migration_connect()..
>
> But since that's the only user of migration_tls_channel_connect(), I assume
> it's not a huge deal, anyway.
>
>> ---
>> migration/channel.c | 46 +++++++++++++++++-------------------------
>> migration/channel.h | 4 +---
>> migration/exec.c | 2 +-
>> migration/fd.c | 2 +-
>> migration/file.c | 2 +-
>> migration/migration.c | 11 ++--------
>> migration/migration.h | 3 ++-
>> migration/rdma.c | 2 +-
>> migration/socket.c | 17 ++++++++--------
>> migration/tls.c | 19 ++++++++---------
>> migration/tls.h | 4 +---
>> migration/trace-events | 2 +-
>> 12 files changed, 49 insertions(+), 65 deletions(-)
>>
>> diff --git a/migration/channel.c b/migration/channel.c
>> index ba14f66d85..7243b99108 100644
>> --- a/migration/channel.c
>> +++ b/migration/channel.c
>> @@ -60,38 +60,30 @@ void migration_channel_process_incoming(QIOChannel *ioc)
>> *
>> * @s: Current migration state
>> * @ioc: Channel to which we are connecting
>> - * @error: Error indicating failure to connect, free'd here
>> */
>> -void migration_channel_connect(MigrationState *s,
>> - QIOChannel *ioc,
>> - Error *error)
>> +void migration_channel_connect(MigrationState *s, QIOChannel *ioc)
>> {
>> - trace_migration_set_outgoing_channel(
>> - ioc, object_get_typename(OBJECT(ioc)), error);
>> + trace_migration_set_outgoing_channel(ioc,
>> object_get_typename(OBJECT(ioc)));
>>
>> - if (!error) {
>> - if (migrate_channel_requires_tls_upgrade(ioc)) {
>> - migration_tls_channel_connect(s, ioc, &error);
>> + if (migrate_channel_requires_tls_upgrade(ioc)) {
>> + migration_tls_channel_connect(s, ioc);
>>
>> - if (!error) {
>> - /* tls_channel_connect will call back to this
>> - * function after the TLS handshake,
>> - * so we mustn't call migration_connect until then
>> - */
>> -
>> - return;
>> - }
>> - } else {
>> - QEMUFile *f = qemu_file_new_output(ioc);
>> -
>> - migration_ioc_register_yank(ioc);
>> -
>> - qemu_mutex_lock(&s->qemu_file_lock);
>> - s->to_dst_file = f;
>> - qemu_mutex_unlock(&s->qemu_file_lock);
>> - }
>> + /*
>> + * async: the above will call back to this function after
>> + * the TLS handshake is successfully completed.
>> + */
>> + return;
>> }
>> - migration_connect(s, error);
>> +
>> + QEMUFile *f = qemu_file_new_output(ioc);
>> +
>> + migration_ioc_register_yank(ioc);
>> +
>> + qemu_mutex_lock(&s->qemu_file_lock);
>> + s->to_dst_file = f;
>> + qemu_mutex_unlock(&s->qemu_file_lock);
>> +
>> + migration_connect(s);
>> }
>>
>>
>> diff --git a/migration/channel.h b/migration/channel.h
>> index 2215091323..ccfeaaef18 100644
>> --- a/migration/channel.h
>> +++ b/migration/channel.h
>> @@ -20,9 +20,7 @@
>>
>> void migration_channel_process_incoming(QIOChannel *ioc);
>>
>> -void migration_channel_connect(MigrationState *s,
>> - QIOChannel *ioc,
>> - Error *error_in);
>> +void migration_channel_connect(MigrationState *s, QIOChannel *ioc);
>>
>> int migration_channel_read_peek(QIOChannel *ioc,
>> const char *buf,
>> diff --git a/migration/exec.c b/migration/exec.c
>> index 78fe0fff13..d83a07435a 100644
>> --- a/migration/exec.c
>> +++ b/migration/exec.c
>> @@ -55,7 +55,7 @@ void exec_start_outgoing_migration(MigrationState *s,
>> strList *command,
>> }
>>
>> qio_channel_set_name(ioc, "migration-exec-outgoing");
>> - migration_channel_connect(s, ioc, NULL);
>> + migration_channel_connect(s, ioc);
>> object_unref(OBJECT(ioc));
>> }
>>
>> diff --git a/migration/fd.c b/migration/fd.c
>> index c956b260a4..0144a70742 100644
>> --- a/migration/fd.c
>> +++ b/migration/fd.c
>> @@ -70,7 +70,7 @@ void fd_start_outgoing_migration(MigrationState *s, const
>> char *fdname, Error **
>> }
>>
>> qio_channel_set_name(ioc, "migration-fd-outgoing");
>> - migration_channel_connect(s, ioc, NULL);
>> + migration_channel_connect(s, ioc);
>> object_unref(OBJECT(ioc));
>> }
>>
>> diff --git a/migration/file.c b/migration/file.c
>> index c490f2b219..7bb9c1c79f 100644
>> --- a/migration/file.c
>> +++ b/migration/file.c
>> @@ -122,7 +122,7 @@ void file_start_outgoing_migration(MigrationState *s,
>> return;
>> }
>> qio_channel_set_name(ioc, "migration-file-outgoing");
>> - migration_channel_connect(s, ioc, NULL);
>> + migration_channel_connect(s, ioc);
>> }
>>
>> static gboolean file_accept_incoming_migration(QIOChannel *ioc,
>> diff --git a/migration/migration.c b/migration/migration.c
>> index a66b2d7aaf..5c6c76f110 100644
>> --- a/migration/migration.c
>> +++ b/migration/migration.c
>> @@ -1572,7 +1572,7 @@ static void migrate_error_free(MigrationState *s)
>> }
>> }
>>
>> -static void migration_connect_error_propagate(MigrationState *s, Error
>> *error)
>> +void migration_connect_error_propagate(MigrationState *s, Error *error)
>> {
>> MigrationStatus current = s->state;
>> MigrationStatus next = MIGRATION_STATUS_NONE;
>> @@ -4033,7 +4033,7 @@ fail_setup:
>> return NULL;
>> }
>>
>> -void migration_connect(MigrationState *s, Error *error_in)
>> +void migration_connect(MigrationState *s)
>> {
>> Error *local_err = NULL;
>> uint64_t rate_limit;
>> @@ -4041,13 +4041,6 @@ void migration_connect(MigrationState *s, Error
>> *error_in)
>> int ret;
>>
>> s->expected_downtime = migrate_downtime_limit();
>> - if (error_in) {
>> - migration_connect_error_propagate(s, error_in);
>> - if (s->error) {
>> - error_report_err(error_copy(s->error));
>> - }
>> - return;
>> - }
>>
>> if (resume) {
>> /* This is a resumed migration */
>> diff --git a/migration/migration.h b/migration/migration.h
>> index 4d42e8f9a7..f340cd518d 100644
>> --- a/migration/migration.h
>> +++ b/migration/migration.h
>> @@ -532,10 +532,11 @@ void migration_incoming_process(void);
>>
>> bool migration_has_all_channels(void);
>>
>> +void migration_connect_error_propagate(MigrationState *s, Error *error);
>> void migrate_error_propagate(MigrationState *s, Error *error);
>> bool migrate_has_error(MigrationState *s);
>>
>> -void migration_connect(MigrationState *s, Error *error_in);
>> +void migration_connect(MigrationState *s);
>>
>> int migration_call_notifiers(MigrationState *s, MigrationEventType type,
>> Error **errp);
>> diff --git a/migration/rdma.c b/migration/rdma.c
>> index 337b415889..596a1aba0b 100644
>> --- a/migration/rdma.c
>> +++ b/migration/rdma.c
>> @@ -3997,7 +3997,7 @@ void rdma_start_outgoing_migration(void *opaque,
>>
>> s->to_dst_file = rdma_new_output(rdma);
>> s->rdma_migration = true;
>> - migration_connect(s, NULL);
>> + migration_connect(s);
>> return;
>> return_path_err:
>> qemu_rdma_cleanup(rdma);
>> diff --git a/migration/socket.c b/migration/socket.c
>> index 426f363b99..298bac30cc 100644
>> --- a/migration/socket.c
>> +++ b/migration/socket.c
>> @@ -59,24 +59,25 @@ static void socket_outgoing_migration(QIOTask *task,
>> gpointer opaque)
>> {
>> struct SocketConnectData *data = opaque;
>> - QIOChannel *sioc = QIO_CHANNEL(qio_task_get_source(task));
>> + g_autoptr(QIOChannel) sioc = QIO_CHANNEL(qio_task_get_source(task));
>> Error *err = NULL;
>>
>> if (qio_task_propagate_error(task, &err)) {
>> - trace_migration_socket_outgoing_error(error_get_pretty(err));
>> - goto out;
>> + goto err;
>> }
>>
>> - trace_migration_socket_outgoing_connected();
>> -
>> if (migrate_zero_copy_send() &&
>> !qio_channel_has_feature(sioc,
>> QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY)) {
>> error_setg(&err, "Zero copy send feature not detected in host
>> kernel");
>> + goto err;
>> }
>>
>> -out:
>> - migration_channel_connect(data->s, sioc, err);
>> - object_unref(OBJECT(sioc));
>> + trace_migration_socket_outgoing_connected();
>> + migration_channel_connect(data->s, sioc);
>> + return;
>> +err:
>> + trace_migration_socket_outgoing_error(error_get_pretty(err));
>> + migration_connect_error_propagate(data->s, err);
>> }
>>
>> void socket_start_outgoing_migration(MigrationState *s,
>> diff --git a/migration/tls.c b/migration/tls.c
>> index 82f58cbc78..a54e8e6e14 100644
>> --- a/migration/tls.c
>> +++ b/migration/tls.c
>> @@ -104,16 +104,17 @@ static void migration_tls_outgoing_handshake(QIOTask
>> *task,
>> gpointer opaque)
>> {
>> MigrationState *s = opaque;
>> - QIOChannel *ioc = QIO_CHANNEL(qio_task_get_source(task));
>> + g_autoptr(QIOChannel) ioc = QIO_CHANNEL(qio_task_get_source(task));
>> Error *err = NULL;
>>
>> if (qio_task_propagate_error(task, &err)) {
>> trace_migration_tls_outgoing_handshake_error(error_get_pretty(err));
>> - } else {
>> - trace_migration_tls_outgoing_handshake_complete();
>> + migration_connect_error_propagate(s, err);
>> + return;
>> }
>> - migration_channel_connect(s, ioc, err);
>> - object_unref(OBJECT(ioc));
>> +
>> + trace_migration_tls_outgoing_handshake_complete();
>> + migration_channel_connect(s, ioc);
>> }
>>
>> QIOChannelTLS *migration_tls_client_create(QIOChannel *ioc,
>> @@ -129,14 +130,14 @@ QIOChannelTLS *migration_tls_client_create(QIOChannel
>> *ioc,
>> return qio_channel_tls_new_client(ioc, creds, migrate_tls_hostname(),
>> errp);
>> }
>>
>> -void migration_tls_channel_connect(MigrationState *s,
>> - QIOChannel *ioc,
>> - Error **errp)
>> +void migration_tls_channel_connect(MigrationState *s, QIOChannel *ioc)
>> {
>> QIOChannelTLS *tioc;
>> + Error *local_err = NULL;
>>
>> - tioc = migration_tls_client_create(ioc, errp);
>> + tioc = migration_tls_client_create(ioc, &local_err);
>> if (!tioc) {
>> + migration_connect_error_propagate(s, local_err);
>> return;
>> }
>>
>> diff --git a/migration/tls.h b/migration/tls.h
>> index 7cd9c76013..7399c42edf 100644
>> --- a/migration/tls.h
>> +++ b/migration/tls.h
>> @@ -29,9 +29,7 @@ void migration_tls_channel_process_incoming(QIOChannel
>> *ioc, Error **errp);
>> QIOChannelTLS *migration_tls_client_create(QIOChannel *ioc,
>> Error **errp);
>>
>> -void migration_tls_channel_connect(MigrationState *s,
>> - QIOChannel *ioc,
>> - Error **errp);
>> +void migration_tls_channel_connect(MigrationState *s, QIOChannel *ioc);
>> void migration_tls_channel_end(QIOChannel *ioc, Error **errp);
>> /* Whether the QIO channel requires further TLS handshake? */
>> bool migrate_channel_requires_tls_upgrade(QIOChannel *ioc);
>> diff --git a/migration/trace-events b/migration/trace-events
>> index da8f909cac..cbf10d0b63 100644
>> --- a/migration/trace-events
>> +++ b/migration/trace-events
>> @@ -204,7 +204,7 @@ migration_transferred_bytes(uint64_t qemu_file, uint64_t
>> multifd, uint64_t rdma)
>>
>> # channel.c
>> migration_set_incoming_channel(void *ioc, const char *ioctype) "ioc=%p
>> ioctype=%s"
>> -migration_set_outgoing_channel(void *ioc, const char *ioctype, void *err)
>> "ioc=%p ioctype=%s err=%p"
>> +migration_set_outgoing_channel(void *ioc, const char *ioctype) "ioc=%p
>> ioctype=%s"
>>
>> # global_state.c
>> migrate_state_too_big(void) ""
>> --
>> 2.51.0
>>
