[PULL 53/65] migration/rdma: Silence qemu_rdma_connect()

[Juan Quintela]

From: Markus Armbruster <armbru@redhat.com>

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.

Bonus: resolves a FIXME about problematic use of errno.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <20230928132019.2544702-47-armbru@redhat.com>
---
 migration/rdma.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/migration/rdma.c b/migration/rdma.c
index 3c7a407d25..8e1e8c4d47 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -2608,8 +2608,8 @@ 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;
     }
 
@@ -2618,21 +2618,15 @@ 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) {
-        /*
-         * FIXME perror() is wrong, because
-         * qemu_get_cm_event_timeout() can fail without setting errno.
-         * Will go away later in this series.
-         */
-        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