migration/rdma: Simplify the function that saves a page

When we sent a page through QEMUFile hooks (RDMA) there are three
posiblities:
- We are not using RDMA. return RAM_SAVE_CONTROL_DELAYED and
  control_save_page() returns false to let anything else to proceed.
- There is one error but we are using RDMA.  Then we return a negative
  value, control_save_page() needs to return true.
- Everything goes well and RDMA start the sent of the page
  asynchronously.  It returns RAM_SAVE_CONTROL_DELAYED and we need to
  return 1 for ram_save_page_legacy.

Clear?

I know, I know, the interface is as bad as it gets.  I think that now
it is a bit clearer, but this needs to be done some other way.

Reviewed-by: Leonardo Bras <leobras@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230515195709.63843-16-quintela@redhat.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/migration/qemu-file.h b/migration/qemu-file.h
index 57b00c8562..03e718c264 100644
--- a/migration/qemu-file.h
+++ b/migration/qemu-file.h
@@ -49,11 +49,10 @@ typedef int (QEMURamHookFunc)(QEMUFile *f, uint64_t flags, void *data);
  * This function allows override of where the RAM page
  * is saved (such as RDMA, for example.)
  */
-typedef size_t (QEMURamSaveFunc)(QEMUFile *f,
-                                 ram_addr_t block_offset,
-                                 ram_addr_t offset,
-                                 size_t size,
-                                 uint64_t *bytes_sent);
+typedef int (QEMURamSaveFunc)(QEMUFile *f,
+                              ram_addr_t block_offset,
+                              ram_addr_t offset,
+                              size_t size);
 
 typedef struct QEMUFileHooks {
     QEMURamHookFunc *before_ram_iterate;
@@ -142,9 +141,8 @@ void ram_control_load_hook(QEMUFile *f, uint64_t flags, void *data);
 #define RAM_SAVE_CONTROL_NOT_SUPP -1000
 #define RAM_SAVE_CONTROL_DELAYED  -2000
 
-size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
-                             ram_addr_t offset, size_t size,
-                             uint64_t *bytes_sent);
+int ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
+                          ram_addr_t offset, size_t size);
 QIOChannel *qemu_file_get_ioc(QEMUFile *file);
 
 #endif