migration: Unfold control_save_page()

control_save_page() is for RDMA only, unfold it to make the code more
clear.
In addition:
 - Similar to other branches style in ram_save_target_page(), involve RDMA
   only if the condition 'migrate_rdma()' is true.
 - Further simplify the code by removing the RAM_SAVE_CONTROL_NOT_SUPP.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Message-ID: <20250305062825.772629-6-lizhijian@fujitsu.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>

3 files changed, 10 insertions, 34 deletions

diff --git a/migration/ram.c b/migration/ram.c
index cb8b2ed493..1181a99cf6 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1144,32 +1144,6 @@ static int save_zero_page(RAMState *rs, PageSearchStatus *pss,
 }
 
 /*
- * @pages: the number of pages written by the control path,
- *        < 0 - error
- *        > 0 - number of pages written
- *
- * Return true if the pages has been saved, otherwise false is returned.
- */
-static bool control_save_page(PageSearchStatus *pss,
-                              ram_addr_t offset, int *pages)
-{
-    int ret;
-
-    ret = rdma_control_save_page(pss->pss_channel, pss->block->offset, offset,
-                                 TARGET_PAGE_SIZE);
-    if (ret == RAM_SAVE_CONTROL_NOT_SUPP) {
-        return false;
-    }
-
-    if (ret == RAM_SAVE_CONTROL_DELAYED) {
-        *pages = 1;
-        return true;
-    }
-    *pages = ret;
-    return true;
-}
-
-/*
  * directly send the page to the stream
  *
  * Returns the number of pages written.
@@ -1965,7 +1939,13 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss)
     int res;
 
     /* Hand over to RDMA first */
-    if (control_save_page(pss, offset, &res)) {
+    if (migrate_rdma()) {
+        res = rdma_control_save_page(pss->pss_channel, pss->block->offset,
+                                     offset, TARGET_PAGE_SIZE);
+
+        if (res == RAM_SAVE_CONTROL_DELAYED) {
+            res = 1;
+        }
         return res;
     }
 
diff --git a/migration/rdma.c b/migration/rdma.c
index a3c3b432d1..4875ca1987 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -3284,14 +3284,11 @@ err:
 int rdma_control_save_page(QEMUFile *f, ram_addr_t block_offset,
                            ram_addr_t offset, size_t size)
 {
-    if (!migrate_rdma()) {
-        return RAM_SAVE_CONTROL_NOT_SUPP;
-    }
+    assert(migrate_rdma());
 
     int ret = qemu_rdma_save_page(f, block_offset, offset, size);
 
-    if (ret != RAM_SAVE_CONTROL_DELAYED &&
-        ret != RAM_SAVE_CONTROL_NOT_SUPP) {
+    if (ret != RAM_SAVE_CONTROL_DELAYED) {
         if (ret < 0) {
             qemu_file_set_error(f, ret);
         }
diff --git a/migration/rdma.h b/migration/rdma.h
index 4d3386b84a..f74f16a459 100644
--- a/migration/rdma.h
+++ b/migration/rdma.h
@@ -33,7 +33,6 @@ void rdma_start_incoming_migration(InetSocketAddress *host_port, Error **errp);
 #define RAM_CONTROL_ROUND     1
 #define RAM_CONTROL_FINISH    3
 
-#define RAM_SAVE_CONTROL_NOT_SUPP -1000
 #define RAM_SAVE_CONTROL_DELAYED  -2000
 
 #ifdef CONFIG_RDMA
@@ -56,7 +55,7 @@ static inline
 int rdma_control_save_page(QEMUFile *f, ram_addr_t block_offset,
                            ram_addr_t offset, size_t size)
 {
-    return RAM_SAVE_CONTROL_NOT_SUPP;
+    g_assert_not_reached();
 }
 #endif
 #endif