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_connect() violates this principle: it calls error_report()
and perror().  I elected not to investigate how callers handle the
error, i.e. precise impact is not known.

Clean this up: replace perror() by changing error_setg() to
error_setg_errno(), and drop error_report().  I believe the callers'
error reports suffice then.  If they don't, we need to convert to
Error instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 migration/rdma.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/migration/rdma.c b/migration/rdma.c
index 0e365db06a..bf4e67d68d 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -2574,8 +2574,8 @@ static int qemu_rdma_connect(RDMAContext *rdma, bool return_path,
 
     ret = rdma_connect(rdma->cm_id, &conn_param);
     if (ret < 0) {
-        perror("rdma_connect");
-        error_setg(errp, "RDMA ERROR: connecting to destination!");
+        error_setg_errno(errp, errno,
+                         "RDMA ERROR: connecting to destination!");
         goto err_rdma_source_connect;
     }
 
@@ -2584,16 +2584,15 @@ static int qemu_rdma_connect(RDMAContext *rdma, bool return_path,
     } else {
         ret = rdma_get_cm_event(rdma->channel, &cm_event);
         if (ret < 0) {
-            error_setg(errp, "RDMA ERROR: failed to get cm event");
+            error_setg_errno(errp, errno,
+                             "RDMA ERROR: failed to get cm event");
         }
     }
     if (ret < 0) {
-        perror("rdma_get_cm_event after rdma_connect");
         goto err_rdma_source_connect;
     }
 
     if (cm_event->event != RDMA_CM_EVENT_ESTABLISHED) {
-        error_report("rdma_get_cm_event != EVENT_ESTABLISHED after rdma_connect");
         error_setg(errp, "RDMA ERROR: connecting to destination!");
         rdma_ack_cm_event(cm_event);
         goto err_rdma_source_connect;
-- 
2.41.0

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_connect() violates this principle: it calls error_report()
> and perror().  I elected not to investigate how callers handle the
> error, i.e. precise impact is not known.
> 
> Clean this up: replace perror() by changing error_setg() to
> error_setg_errno(), and drop error_report().  I believe the callers'
> error reports suffice then.  If they don't, we need to convert to
> Error instead.
> 
> Signed-off-by: Markus Armbruster<armbru@redhat.com>

Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>