Instead introduce a extra parameter to trigger the compress thread.
Now, when the compress thread is done, we know what RAMBlock and
offset it did compress.

This will be used in the next commits to move save_page_header()
out of compress code.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 migration/ram.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index ade6638a96..820b4ebaeb 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -503,6 +503,7 @@ typedef enum CompressResult CompressResult;
 struct CompressParam {
     bool done;
     bool quit;
+    bool trigger;
     CompressResult result;
     QEMUFile *file;
     QemuMutex mutex;
@@ -576,10 +577,10 @@ static void *do_data_compress(void *opaque)

     qemu_mutex_lock(&param->mutex);
     while (!param->quit) {
-        if (param->block) {
+        if (param->trigger) {
             block = param->block;
             offset = param->offset;
-            param->block = NULL;
+            param->trigger = false;
             qemu_mutex_unlock(&param->mutex);

             result = do_compress_ram_page(param->file, &param->stream,
@@ -1556,6 +1557,7 @@ static inline void set_compress_params(CompressParam *param, RAMBlock *block,
 {
     param->block = block;
     param->offset = offset;
+    param->trigger = true;
 }

 static int compress_page_with_multi_thread(RAMBlock *block, ram_addr_t offset)
--
2.40.0

Lukas Straub <lukasstraub2@web.de> wrote:
> Instead introduce a extra parameter to trigger the compress thread.
> Now, when the compress thread is done, we know what RAMBlock and
> offset it did compress.
>
> This will be used in the next commits to move save_page_header()
> out of compress code.
>
> Signed-off-by: Lukas Straub <lukasstraub2@web.de>

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

Much better, thanks.