Re: [PATCH 2/3] migration: Make save_snapshot() return bool, not 0/-1

[Pavel Dovgalyuk]

On 08.10.2020 20:48, Philippe Mathieu-Daudé wrote:

Just for consistency, following the example documented since
commit e3fe3988d7 ("error: Document Error API usage rules").
Document the function.

Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>

Acked-by: Pavel Dovgalyuk <pavel.dovgal...@ispras.ru>

---
  include/migration/snapshot.h |  9 ++++++++-
  migration/savevm.c           | 16 ++++++++--------
  replay/replay-debugging.c    |  2 +-
  replay/replay-snapshot.c     |  2 +-
  4 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/include/migration/snapshot.h b/include/migration/snapshot.h
index c85b6ec75b..a40c34307b 100644
--- a/include/migration/snapshot.h
+++ b/include/migration/snapshot.h
@@ -15,7 +15,14 @@
  #ifndef QEMU_MIGRATION_SNAPSHOT_H
  #define QEMU_MIGRATION_SNAPSHOT_H

-int save_snapshot(const char *name, Error **errp);

+/**
+ * save_snapshot: Save a snapshot.
+ * @name: path to snapshot
+ * @errp: pointer to error object
+ * On success, return %true.
+ * On failure, store an error through @errp and return %false.
+ */
+bool save_snapshot(const char *name, Error **errp);
  int load_snapshot(const char *name, Error **errp);

#endif

diff --git a/migration/savevm.c b/migration/savevm.c
index a52da440f4..fd2e5e8b66 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -2658,7 +2658,7 @@ int qemu_load_device_state(QEMUFile *f)
      return 0;
  }

-int save_snapshot(const char *name, Error **errp)

+bool save_snapshot(const char *name, Error **errp)
  {
      BlockDriverState *bs;
      QEMUSnapshotInfo sn1, *sn = &sn1, old_sn1, *old_sn = &old_sn1;
@@ -2671,29 +2671,29 @@ int save_snapshot(const char *name, Error **errp)
      AioContext *aio_context;

if (migration_is_blocked(errp)) {

-        return ret;
+        return false;
      }

if (!replay_can_snapshot()) {

          error_setg(errp, "Record/replay does not allow making snapshot "
                     "right now. Try once more later.");
-        return ret;
+        return false;
      }

if (!bdrv_all_can_snapshot(errp)) {

-        return ret;
+        return false;
      }

/* Delete old snapshots of the same name */

      if (name) {
          if (bdrv_all_delete_snapshot(name, errp) < 0) {
-            return ret;
+            return false;
          }
      }

bs = bdrv_all_find_vmstate_bs(errp);

      if (bs == NULL) {
-        return ret;
+        return false;
      }
      aio_context = bdrv_get_aio_context(bs);

@@ -2702,7 +2702,7 @@ int save_snapshot(const char *name, Error **errp)

      ret = global_state_store();
      if (ret) {
          error_setg(errp, "Error saving global state");
-        return ret;
+        return false;
      }
      vm_stop(RUN_STATE_SAVE_VM);

@@ -2779,7 +2779,7 @@ int save_snapshot(const char *name, Error **errp)

      if (saved_vm_running) {
          vm_start();
      }
-    return ret;
+    return ret == 0;
  }

void qmp_xen_save_devices_state(const char *filename, bool has_live, bool live,

diff --git a/replay/replay-debugging.c b/replay/replay-debugging.c
index 8785489c02..5458a73fce 100644
--- a/replay/replay-debugging.c
+++ b/replay/replay-debugging.c
@@ -327,7 +327,7 @@ void replay_gdb_attached(void)
       */
      if (replay_mode == REPLAY_MODE_PLAY
          && !replay_snapshot) {
-        if (save_snapshot("start_debugging", NULL) != 0) {
+        if (!save_snapshot("start_debugging", NULL)) {
              /* Can't create the snapshot. Continue conventional debugging. */
          }
      }
diff --git a/replay/replay-snapshot.c b/replay/replay-snapshot.c
index e26fa4c892..4f2560d156 100644
--- a/replay/replay-snapshot.c
+++ b/replay/replay-snapshot.c
@@ -77,7 +77,7 @@ void replay_vmstate_init(void)

if (replay_snapshot) {

          if (replay_mode == REPLAY_MODE_RECORD) {
-            if (save_snapshot(replay_snapshot, &err) != 0) {
+            if (!save_snapshot(replay_snapshot, &err)) {
                  error_report_err(err);
                  error_report("Could not create snapshot for icount record");
                  exit(1);