migrate_set_error() used one error_copy() so it always copy an error.
However that's not the major use case - the major use case is one would
like to pass the error to migrate_set_error() without further touching the
error.
It can be proved if we see most of the callers are freeing the error
explicitly right afterwards. There're a few outliers (only if when the
caller) where we can use error_copy() explicitly there.
Signed-off-by: Peter Xu <pet...@redhat.com>
---
migration/migration.h | 6 +++---
migration/channel.c | 1 -
migration/migration.c | 20 ++++++++++++++------
migration/multifd.c | 10 ++++------
migration/postcopy-ram.c | 1 -
migration/ram.c | 1 -
6 files changed, 21 insertions(+), 18 deletions(-)
diff --git a/migration/migration.h b/migration/migration.h
index 721b1c9473..32f87e3834 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -468,8 +468,8 @@ bool migration_has_all_channels(void);
uint64_t migrate_max_downtime(void);
-void migrate_set_error(MigrationState *s, const Error *error);
-void migrate_fd_error(MigrationState *s, const Error *error);
+void migrate_set_error(MigrationState *s, Error *error);
+void migrate_fd_error(MigrationState *s, Error *error);
void migrate_fd_connect(MigrationState *s, Error *error_in);
@@ -513,7 +513,7 @@ int foreach_not_ignored_block(RAMBlockIterFunc func, void
*opaque);
void migration_make_urgent_request(void);
void migration_consume_urgent_request(void);
bool migration_rate_limit(void);
-void migration_cancel(const Error *error);
+void migration_cancel(Error *error);
void populate_vfio_info(MigrationInfo *info);
void postcopy_temp_page_reset(PostcopyTmpPage *tmp_page);
diff --git a/migration/channel.c b/migration/channel.c
index ca3319a309..48b3f6abd6 100644
--- a/migration/channel.c
+++ b/migration/channel.c
@@ -90,7 +90,6 @@ void migration_channel_connect(MigrationState *s,
}
}
migrate_fd_connect(s, error);
- error_free(error);
}
diff --git a/migration/migration.c b/migration/migration.c
index 203d40d4c9..13dccc4c12 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -160,7 +160,7 @@ void migration_object_init(void)
dirty_bitmap_mig_init();
}
-void migration_cancel(const Error *error)
+void migration_cancel(Error *error)
{
if (error) {
migrate_set_error(current_migration, error);
@@ -1197,11 +1197,20 @@ static void migrate_fd_cleanup_bh(void *opaque)
object_unref(OBJECT(s));
}
-void migrate_set_error(MigrationState *s, const Error *error)
+/*
+ * Set error for current migration state. The `error' ownership will be
+ * moved from the caller to MigrationState, so the caller doesn't need to
+ * free the error.
+ *
+ * If the caller still needs to reference the `error' passed in, one should
+ * use error_copy() explicitly.
+ */
+void migrate_set_error(MigrationState *s, Error *error)
{
QEMU_LOCK_GUARD(&s->error_mutex);
if (!s->error) {
- s->error = error_copy(error);
+ /* Record the first error triggered */
+ s->error = error;
}
}
@@ -1214,7 +1223,7 @@ static void migrate_error_free(MigrationState *s)
}
}
-void migrate_fd_error(MigrationState *s, const Error *error)
+void migrate_fd_error(MigrationState *s, Error *error)
{
trace_migrate_fd_error(error_get_pretty(error));
assert(s->to_dst_file == NULL);
@@ -1678,7 +1687,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
if (!(has_resume && resume)) {
yank_unregister_instance(MIGRATION_YANK_INSTANCE);
}
- migrate_fd_error(s, local_err);
+ migrate_fd_error(s, error_copy(local_err));
error_propagate(errp, local_err);
return;
}
@@ -2595,7 +2604,6 @@ static MigThrError migration_detect_error(MigrationState
*s)
if (local_error) {
migrate_set_error(s, local_error);
- error_free(local_error);
}
if (state == MIGRATION_STATUS_POSTCOPY_ACTIVE && ret) {
diff --git a/migration/multifd.c b/migration/multifd.c
index 3387d8277f..62bc2dbf49 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -551,7 +551,6 @@ void multifd_save_cleanup(void)
multifd_send_state->ops->send_cleanup(p, &local_err);
if (local_err) {
migrate_set_error(migrate_get_current(), local_err);
- error_free(local_err);
}
}
qemu_sem_destroy(&multifd_send_state->channels_ready);
@@ -750,7 +749,6 @@ out:
if (local_err) {
trace_multifd_send_error(p->id);
multifd_send_terminate_threads(local_err);
- error_free(local_err);
}
/*
@@ -883,7 +881,6 @@ static void
multifd_new_send_channel_cleanup(MultiFDSendParams *p,
*/
p->quit = true;
object_unref(OBJECT(ioc));
- error_free(err);
}
static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque)
@@ -1148,7 +1145,6 @@ static void *multifd_recv_thread(void *opaque)
if (local_err) {
multifd_recv_terminate_threads(local_err);
- error_free(local_err);
}
qemu_mutex_lock(&p->mutex);
p->running = false;
@@ -1240,7 +1236,8 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
**errp)
id = multifd_recv_initial_packet(ioc, &local_err);
if (id < 0) {
- multifd_recv_terminate_threads(local_err);
+ /* Copy local error because we'll also return it to caller */
+ multifd_recv_terminate_threads(error_copy(local_err));
error_propagate_prepend(errp, local_err,
"failed to receive packet"
" via multifd channel %d: ",
@@ -1253,7 +1250,8 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
**errp)
if (p->c != NULL) {
error_setg(&local_err, "multifd: received id '%d' already setup'",
id);
- multifd_recv_terminate_threads(local_err);
+ /* Copy local error because we'll also return it to caller */
+ multifd_recv_terminate_threads(error_copy(local_err));
error_propagate(errp, local_err);
return;
}
diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
index 5615ec29eb..6f6fb52bf1 100644
--- a/migration/postcopy-ram.c
+++ b/migration/postcopy-ram.c
@@ -1594,7 +1594,6 @@ postcopy_preempt_send_channel_done(MigrationState *s,
{
if (local_err) {
migrate_set_error(s, local_err);
- error_free(local_err);
} else {
migration_ioc_register_yank(ioc);
s->postcopy_qemufile_src = qemu_file_new_output(ioc);
diff --git a/migration/ram.c b/migration/ram.c
index 5283a75f02..ba4890563d 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -4267,7 +4267,6 @@ static void ram_mig_ram_block_resized(RAMBlockNotifier
*n, void *host,
*/
error_setg(&err, "RAM block '%s' resized during precopy.", rb->idstr);
migration_cancel(err);
- error_free(err);
}
switch (ps) {
--
2.41.0
