Re: [PATCH 50/52] migration/rdma: Silence qemu_rdma_cleanup()

[Zhijian Li (Fujitsu)]

On 18/09/2023 22:42, Markus Armbruster wrote:
> Functions that use an Error **errp parameter to return errors should
> not also report them to the user, because reporting is the caller's
> job.  When the caller does, the error is reported twice.  When it
> doesn't (because it recovered from the error), there is no error to
> report, i.e. the report is bogus.
> 
> qemu_rdma_source_init(), qemu_rdma_connect(),
> rdma_start_incoming_migration(), and rdma_start_outgoing_migration()
> violate this principle: they call error_report() via
> qemu_rdma_cleanup().
> 
> Moreover, qemu_rdma_cleanup() can't fail.  It is called on error
> paths, and QIOChannel close and finalization.  Are the conditions it
> reports really errors?  I doubt it.

I'm not very sure, it's fine if it's call from the error path. but when
the caller is migration_cancle from HMP/QMP, shall we report something more
though we know QEMU can recover.

maybe change to warning etc...




> 
> Clean this up: silence qemu_rdma_cleanup().  I believe that's fine for
> all these callers.  If it isn't, we need to convert to Error instead.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>   migration/rdma.c | 6 +-----
>   1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/migration/rdma.c b/migration/rdma.c
> index d9f80ef390..be2db7946d 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -2330,7 +2330,6 @@ static int qemu_rdma_write(QEMUFile *f, RDMAContext 
> *rdma,
>   
>   static void qemu_rdma_cleanup(RDMAContext *rdma)
>   {
> -    Error *err = NULL;
>       int idx;
>   
>       if (rdma->cm_id && rdma->connected) {
> @@ -2341,10 +2340,7 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
>                                          .type = RDMA_CONTROL_ERROR,
>                                          .repeat = 1,
>                                        };
> -            error_report("Early error. Sending error.");
> -            if (qemu_rdma_post_send_control(rdma, NULL, &head, &err) < 0) {
> -                error_report_err(err);
> -            }
> +            qemu_rdma_post_send_control(rdma, NULL, &head, NULL);
>           }
>   
>           rdma_disconnect(rdma->cm_id);