[PULL 10/16] migration/rdma: Check for postcopy sooner

[Juan Quintela <quintela@redhat.com>]

It makes no sense first try to see if there is an rdma error and then
do nothing on postcopy stage.  Change it so we check we are in
postcopy before doing anything.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20230504114443.23891-6-quintela@redhat.com>
---
 migration/rdma.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/migration/rdma.c b/migration/rdma.c
index 17c4b9206f..2cd8f1cc66 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -3234,19 +3234,19 @@ static size_t qemu_rdma_save_page(QEMUFile *f,
     RDMAContext *rdma;
     int ret;
 
-    RCU_READ_LOCK_GUARD();
-    rdma = qatomic_rcu_read(&rioc->rdmaout);
-
-    if (!rdma) {
-        return -EIO;
-    }
-
-    CHECK_ERROR_STATE();
-
     if (migration_in_postcopy()) {
         return RAM_SAVE_CONTROL_NOT_SUPP;
     }
 
+    RCU_READ_LOCK_GUARD();
+    rdma = qatomic_rcu_read(&rioc->rdmaout);
+
+    if (!rdma) {
+        return -EIO;
+    }
+
+    CHECK_ERROR_STATE();
+
     qemu_fflush(f);
 
     /*
@@ -3866,6 +3866,10 @@ static int qemu_rdma_registration_start(QEMUFile *f,
     QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(qemu_file_get_ioc(f));
     RDMAContext *rdma;
 
+    if (migration_in_postcopy()) {
+        return 0;
+    }
+
     RCU_READ_LOCK_GUARD();
     rdma = qatomic_rcu_read(&rioc->rdmaout);
     if (!rdma) {
@@ -3874,10 +3878,6 @@ static int qemu_rdma_registration_start(QEMUFile *f,
 
     CHECK_ERROR_STATE();
 
-    if (migration_in_postcopy()) {
-        return 0;
-    }
-
     trace_qemu_rdma_registration_start(flags);
     qemu_put_be64(f, RAM_SAVE_FLAG_HOOK);
     qemu_fflush(f);
@@ -3897,6 +3897,10 @@ static int qemu_rdma_registration_stop(QEMUFile *f,
     RDMAControlHeader head = { .len = 0, .repeat = 1 };
     int ret = 0;
 
+    if (migration_in_postcopy()) {
+        return 0;
+    }
+
     RCU_READ_LOCK_GUARD();
     rdma = qatomic_rcu_read(&rioc->rdmaout);
     if (!rdma) {
@@ -3905,10 +3909,6 @@ static int qemu_rdma_registration_stop(QEMUFile *f,
 
     CHECK_ERROR_STATE();
 
-    if (migration_in_postcopy()) {
-        return 0;
-    }
-
     qemu_fflush(f);
     ret = qemu_rdma_drain_cq(f, rdma);
 
-- 
2.40.0