diff mbox series

[v2,37/53] migration/rdma: Convert qemu_rdma_exchange_get_response() to Error

Message ID 20230928132019.2544702-38-armbru@redhat.com
State New
Headers show
Series migration/rdma: Error handling fixes | expand

Commit Message

Markus Armbruster Sept. 28, 2023, 1:20 p.m. UTC 
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_exchange_send() and qemu_rdma_exchange_recv() violate this
principle: they call error_report() via
qemu_rdma_exchange_get_response().  I elected not to investigate how
callers handle the error, i.e. precise impact is not known.

Clean this up by converting qemu_rdma_exchange_get_response() to
Error.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
---
 migration/rdma.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

Comments

Juan Quintela Oct. 4, 2023, 4:55 p.m. UTC | #1 
Markus Armbruster <armbru@redhat.com> 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_exchange_send() and qemu_rdma_exchange_recv() violate this
> principle: they call error_report() via
> qemu_rdma_exchange_get_response().  I elected not to investigate how
> callers handle the error, i.e. precise impact is not known.
>
> Clean this up by converting qemu_rdma_exchange_get_response() to
> Error.
>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>
diff mbox series

Patch

diff --git a/migration/rdma.c b/migration/rdma.c
index f77bf1d453..2f6e22e1f2 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -1824,14 +1824,15 @@  static int qemu_rdma_post_recv_control(RDMAContext *rdma, int idx)
  * Block and wait for a RECV control channel message to arrive.
  */
 static int qemu_rdma_exchange_get_response(RDMAContext *rdma,
-                RDMAControlHeader *head, uint32_t expecting, int idx)
+                RDMAControlHeader *head, uint32_t expecting, int idx,
+                Error **errp)
 {
     uint32_t byte_len;
     int ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RECV_CONTROL + idx,
                                        &byte_len);
 
     if (ret < 0) {
-        error_report("rdma migration: recv polling control error!");
+        error_setg(errp, "rdma migration: recv polling control error!");
         return -1;
     }
 
@@ -1844,7 +1845,7 @@  static int qemu_rdma_exchange_get_response(RDMAContext *rdma,
         trace_qemu_rdma_exchange_get_response_none(control_desc(head->type),
                                              head->type);
     } else if (head->type != expecting || head->type == RDMA_CONTROL_ERROR) {
-        error_report("Was expecting a %s (%d) control message"
+        error_setg(errp, "Was expecting a %s (%d) control message"
                 ", but got: %s (%d), length: %d",
                 control_desc(expecting), expecting,
                 control_desc(head->type), head->type, head->len);
@@ -1854,11 +1855,12 @@  static int qemu_rdma_exchange_get_response(RDMAContext *rdma,
         return -1;
     }
     if (head->len > RDMA_CONTROL_MAX_BUFFER - sizeof(*head)) {
-        error_report("too long length: %d", head->len);
+        error_setg(errp, "too long length: %d", head->len);
         return -1;
     }
     if (sizeof(*head) + head->len != byte_len) {
-        error_report("Malformed length: %d byte_len %d", head->len, byte_len);
+        error_setg(errp, "Malformed length: %d byte_len %d",
+                   head->len, byte_len);
         return -1;
     }
 
@@ -1908,10 +1910,10 @@  static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
      */
     if (rdma->control_ready_expected) {
         RDMAControlHeader resp;
-        ret = qemu_rdma_exchange_get_response(rdma,
-                                    &resp, RDMA_CONTROL_READY, RDMA_WRID_READY);
+        ret = qemu_rdma_exchange_get_response(rdma, &resp,
+                                              RDMA_CONTROL_READY,
+                                              RDMA_WRID_READY, errp);
         if (ret < 0) {
-            error_setg(errp, "FIXME temporary error message");
             return -1;
         }
     }
@@ -1962,10 +1964,10 @@  static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head,
 
         trace_qemu_rdma_exchange_send_waiting(control_desc(resp->type));
         ret = qemu_rdma_exchange_get_response(rdma, resp,
-                                              resp->type, RDMA_WRID_DATA);
+                                              resp->type, RDMA_WRID_DATA,
+                                              errp);
 
         if (ret < 0) {
-            error_setg(errp, "FIXME temporary error message");
             return -1;
         }
 
@@ -2009,10 +2011,9 @@  static int qemu_rdma_exchange_recv(RDMAContext *rdma, RDMAControlHeader *head,
      * Block and wait for the message.
      */
     ret = qemu_rdma_exchange_get_response(rdma, head,
-                                          expecting, RDMA_WRID_READY);
+                                          expecting, RDMA_WRID_READY, errp);
 
     if (ret < 0) {
-        error_setg(errp, "FIXME temporary error message");
         return -1;
     }