Migration fixes

From: "Dr. David Alan Gilbert" <[email protected]>

Hi,
These are 3 migration fixes that fix things I messed up.
Only the 1st one (set last_sent_block) fixes a problem, the other two fix coverity findings.

Dave

Dr. David Alan Gilbert (3):
Set last_sent_block
migration: Dead assignment of current_time
Unneeded NULL check

 migration/migration.c | 3 +--
 migration/ram.c       | 1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

2.5.0

From: "Dr. David Alan Gilbert" <[email protected]>

In a82d593b61054b3dea43 I accidentally removed the setting of last_sent_block, put it back.

Symptoms:
Multithreaded compression only uses one thread. Migration is a bit less efficient since it won't use 'cont' flags.

---
 migration/ram.c | 1 +
 1 file changed, 1 insertion(+)

index 7f32696..1eb155a 100644
@@ -1249,6 +1249,7 @@ static int ram_save_target_page(MigrationState *ms, QEMUFile *f,
         if (unsentmap) {
             clear_bit(dirty_ram_abs >> TARGET_PAGE_BITS, unsentmap);
         }
+        last_sent_block = block;
     }
 
     return res;

2.5.0

From: "Dr. David Alan Gilbert" <[email protected]>

I set current_time before the postcopy test but never use it; (I think this was from the original version where it was time based). Spotted by coverity, CID 1339208

---
 migration/migration.c | 1 -
 1 file changed, 1 deletion(-)

index 7e4e27b..265d13a 100644
@@ -1643,7 +1643,6 @@ static void *migration_thread(void *opaque)
             if (pending_size && pending_size >= max_size) {
                 /* Still a significant amount to transfer */
 
-                current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
                 if (migrate_postcopy_ram() &&
                     s->state != MIGRATION_STATUS_POSTCOPY_ACTIVE &&
                     pend_nonpost <= max_size &&

2.5.0

From: "Dr. David Alan Gilbert" <[email protected]>

The check is unneccesary, we read the value at the start of the thread, use it, and never change it. The value is checked to be non-NULL before thread creation.

Spotted by coverity, CID 1339211

---
 migration/migration.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 265d13a..1a42aee 100644
@@ -1345,7 +1345,7 @@ static void *source_return_path_thread(void *opaque)
             break;
         }
     }
-    if (rp && qemu_file_get_error(rp)) {
+    if (qemu_file_get_error(rp)) {
         trace_source_return_path_thread_bad_end();
         mark_source_rp_bad(ms);
     }

2.5.0