Re: [PATCH V1 03/26] migration: SAVEVM_FOREACH

[Fabiano Rosas <farosas@suse.de>]

Steve Sistare <steven.sistare@oracle.com> writes:

> Define an abstraction SAVEVM_FOREACH to loop over all savevm state
> handlers, and replace QTAILQ_FOREACH.  Define variants for ALL so
> we can loop over all handlers vs a subset of handlers in a subsequent
> patch, but at this time there is no distinction between the two.
> No functional change.
>
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  migration/savevm.c | 55 +++++++++++++++++++++++++++++++-----------------------
>  1 file changed, 32 insertions(+), 23 deletions(-)
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 4509482..6829ba3 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -237,6 +237,15 @@ static SaveState savevm_state = {
>      .global_section_id = 0,
>  };
>  
> +#define SAVEVM_FOREACH(se, entry)                                    \
> +    QTAILQ_FOREACH(se, &savevm_state.handlers, entry)                \
> +
> +#define SAVEVM_FOREACH_ALL(se, entry)                                \
> +    QTAILQ_FOREACH(se, &savevm_state.handlers, entry)

This feels worse than SAVEVM_FOREACH_NOT_PRECREATED. We'll have to keep
coming back to the definition to figure out which FOREACH is the real
deal.

> +
> +#define SAVEVM_FOREACH_SAFE_ALL(se, entry, new_se)                   \
> +    QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se)
> +
>  static SaveStateEntry *find_se(const char *idstr, uint32_t instance_id);
>  
>  static bool should_validate_capability(int capability)
> @@ -674,7 +683,7 @@ static uint32_t calculate_new_instance_id(const char *idstr)
>      SaveStateEntry *se;
>      uint32_t instance_id = 0;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH_ALL(se, entry) {

In this patch we can't have both instances...

>          if (strcmp(idstr, se->idstr) == 0
>              && instance_id <= se->instance_id) {
>              instance_id = se->instance_id + 1;
> @@ -690,7 +699,7 @@ static int calculate_compat_instance_id(const char *idstr)
>      SaveStateEntry *se;
>      int instance_id = 0;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {

...otherwise one of the two changes will go undocumented because the
actual reason for it will only be described in the next patch.

>          if (!se->compat) {
>              continue;
>          }
> @@ -816,7 +825,7 @@ void unregister_savevm(VMStateIf *obj, const char *idstr, void *opaque)
>      }
>      pstrcat(id, sizeof(id), idstr);
>  
> -    QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) {
> +    SAVEVM_FOREACH_SAFE_ALL(se, entry, new_se) {
>          if (strcmp(se->idstr, id) == 0 && se->opaque == opaque) {
>              savevm_state_handler_remove(se);
>              g_free(se->compat);
> @@ -939,7 +948,7 @@ void vmstate_unregister(VMStateIf *obj, const VMStateDescription *vmsd,
>  {
>      SaveStateEntry *se, *new_se;
>  
> -    QTAILQ_FOREACH_SAFE(se, &savevm_state.handlers, entry, new_se) {
> +    SAVEVM_FOREACH_SAFE_ALL(se, entry, new_se) {
>          if (se->vmsd == vmsd && se->opaque == opaque) {
>              savevm_state_handler_remove(se);
>              g_free(se->compat);
> @@ -1223,7 +1232,7 @@ bool qemu_savevm_state_blocked(Error **errp)
>  {
>      SaveStateEntry *se;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->vmsd && se->vmsd->unmigratable) {
>              error_setg(errp, "State blocked by non-migratable device '%s'",
>                         se->idstr);
> @@ -1237,7 +1246,7 @@ void qemu_savevm_non_migratable_list(strList **reasons)
>  {
>      SaveStateEntry *se;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->vmsd && se->vmsd->unmigratable) {
>              QAPI_LIST_PREPEND(*reasons,
>                                g_strdup_printf("non-migratable device: %s",
> @@ -1276,7 +1285,7 @@ bool qemu_savevm_state_guest_unplug_pending(void)
>  {
>      SaveStateEntry *se;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->vmsd && se->vmsd->dev_unplug_pending &&
>              se->vmsd->dev_unplug_pending(se->opaque)) {
>              return true;
> @@ -1291,7 +1300,7 @@ int qemu_savevm_state_prepare(Error **errp)
>      SaveStateEntry *se;
>      int ret;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->save_prepare) {
>              continue;
>          }
> @@ -1321,7 +1330,7 @@ int qemu_savevm_state_setup(QEMUFile *f, Error **errp)
>      json_writer_start_array(ms->vmdesc, "devices");
>  
>      trace_savevm_state_setup();
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->vmsd && se->vmsd->early_setup) {
>              ret = vmstate_save(f, se, ms->vmdesc, errp);
>              if (ret) {
> @@ -1365,7 +1374,7 @@ int qemu_savevm_state_resume_prepare(MigrationState *s)
>  
>      trace_savevm_state_resume_prepare();
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->resume_prepare) {
>              continue;
>          }
> @@ -1396,7 +1405,7 @@ int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy)
>      int ret;
>  
>      trace_savevm_state_iterate();
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->save_live_iterate) {
>              continue;
>          }
> @@ -1461,7 +1470,7 @@ void qemu_savevm_state_complete_postcopy(QEMUFile *f)
>      SaveStateEntry *se;
>      int ret;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->save_live_complete_postcopy) {
>              continue;
>          }
> @@ -1495,7 +1504,7 @@ int qemu_savevm_state_complete_precopy_iterable(QEMUFile *f, bool in_postcopy)
>      SaveStateEntry *se;
>      int ret;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops ||
>              (in_postcopy && se->ops->has_postcopy &&
>               se->ops->has_postcopy(se->opaque)) ||
> @@ -1543,7 +1552,7 @@ int qemu_savevm_state_complete_precopy_non_iterable(QEMUFile *f,
>      Error *local_err = NULL;
>      int ret;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->vmsd && se->vmsd->early_setup) {
>              /* Already saved during qemu_savevm_state_setup(). */
>              continue;
> @@ -1649,7 +1658,7 @@ void qemu_savevm_state_pending_estimate(uint64_t *must_precopy,
>      *must_precopy = 0;
>      *can_postcopy = 0;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->state_pending_estimate) {
>              continue;
>          }
> @@ -1670,7 +1679,7 @@ void qemu_savevm_state_pending_exact(uint64_t *must_precopy,
>      *must_precopy = 0;
>      *can_postcopy = 0;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->state_pending_exact) {
>              continue;
>          }
> @@ -1693,7 +1702,7 @@ void qemu_savevm_state_cleanup(void)
>      }
>  
>      trace_savevm_state_cleanup();
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->ops && se->ops->save_cleanup) {
>              se->ops->save_cleanup(se->opaque);
>          }
> @@ -1778,7 +1787,7 @@ int qemu_save_device_state(QEMUFile *f)
>      }
>      cpu_synchronize_all_states();
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          int ret;
>  
>          if (se->is_ram) {
> @@ -1801,7 +1810,7 @@ static SaveStateEntry *find_se(const char *idstr, uint32_t instance_id)
>  {
>      SaveStateEntry *se;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH_ALL(se, entry) {
>          if (!strcmp(se->idstr, idstr) &&
>              (instance_id == se->instance_id ||
>               instance_id == se->alias_id))
> @@ -2680,7 +2689,7 @@ qemu_loadvm_section_part_end(QEMUFile *f, MigrationIncomingState *mis,
>      }
>  
>      trace_qemu_loadvm_state_section_partend(section_id);
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->load_section_id == section_id) {
>              break;
>          }
> @@ -2755,7 +2764,7 @@ static void qemu_loadvm_state_switchover_ack_needed(MigrationIncomingState *mis)
>  {
>      SaveStateEntry *se;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->switchover_ack_needed) {
>              continue;
>          }
> @@ -2775,7 +2784,7 @@ static int qemu_loadvm_state_setup(QEMUFile *f, Error **errp)
>      int ret;
>  
>      trace_loadvm_state_setup();
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (!se->ops || !se->ops->load_setup) {
>              continue;
>          }
> @@ -2801,7 +2810,7 @@ void qemu_loadvm_state_cleanup(void)
>      SaveStateEntry *se;
>  
>      trace_loadvm_state_cleanup();
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +    SAVEVM_FOREACH(se, entry) {
>          if (se->ops && se->ops->load_cleanup) {
>              se->ops->load_cleanup(se->opaque);
>          }