Re: [PATCH 39/52] migration/rdma: Convert qemu_rdma_write_one() to Error

[Zhijian Li (Fujitsu)]

On 18/09/2023 22:41, 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_write_flush() violates this principle: it calls
> error_report() via qemu_rdma_write_one().  I elected not to
> investigate how callers handle the error, i.e. precise impact is not
> known.
> 
> Clean this up by converting qemu_rdma_write_one() to Error.
> 
> Signed-off-by: Markus Armbruster<armbru@redhat.com>
> ---
>   migration/rdma.c | 25 +++++++++++--------------
>   1 file changed, 11 insertions(+), 14 deletions(-)
> 
> diff --git a/migration/rdma.c b/migration/rdma.c
> index c3c33fe242..9b8cbadfcd 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -2019,9 +2019,8 @@ static int qemu_rdma_exchange_recv(RDMAContext *rdma, 
> RDMAControlHeader *head,
>    */
>   static int qemu_rdma_write_one(QEMUFile *f, RDMAContext *rdma,
>                                  int current_index, uint64_t current_addr,
> -                               uint64_t length)
> +                               uint64_t length, Error **errp)
>   {
> -    Error *err = NULL;
>       struct ibv_sge sge;
>       struct ibv_send_wr send_wr = { 0 };
>       struct ibv_send_wr *bad_wr;

[...]

>           }
> @@ -2219,7 +2216,7 @@ retry:
>           goto retry;
>   
>       } else if (ret > 0) {
> -        perror("rdma migration: post rdma write failed");
> +        error_setg(errp, "rdma migration: post rdma write failed");

It reminds that do you miss to use error_setg_errno() instead.





>           return -1;
>       }