qapi: Use QAPI_LIST_PREPEND() where possible

Anywhere we create a list of just one item or by prepending items
(typically because order doesn't matter), we can use
QAPI_LIST_PREPEND().  But places where we must keep the list in order
by appending remain open-coded until later patches.

Note that as a side effect, this also performs a cleanup of two minor
issues in qga/commands-posix.c: the old code was performing
 new = g_malloc0(sizeof(*ret));
which 1) is confusing because you have to verify whether 'new' and
'ret' are variables with the same type, and 2) would conflict with C++
compilation (not an actual problem for this file, but makes
copy-and-paste harder).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20201113011340.463563-5-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
[Straightforward conflicts due to commit a8aa94b5f8 "qga: update
schema for guest-get-disks 'dependents' field" and commit a10b453a52
"target/mips: Move mips_cpu_add_definition() from helper.c to cpu.c"
resolved.  Commit message tweaked.]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

3 files changed, 21 insertions, 27 deletions

diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
index 65d8ff4849..73b79df7d8 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -1255,7 +1255,8 @@ void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict)
     const char *cap = qdict_get_str(qdict, "capability");
     bool state = qdict_get_bool(qdict, "state");
     Error *err = NULL;
-    MigrationCapabilityStatusList *caps = g_malloc0(sizeof(*caps));
+    MigrationCapabilityStatusList *caps = NULL;
+    MigrationCapabilityStatus *value;
     int val;
 
     val = qapi_enum_parse(&MigrationCapability_lookup, cap, -1, &err);
@@ -1263,14 +1264,14 @@ void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict)
         goto end;
     }
 
-    caps->value = g_malloc0(sizeof(*caps->value));
-    caps->value->capability = val;
-    caps->value->state = state;
-    caps->next = NULL;
+    value = g_malloc0(sizeof(*value));
+    value->capability = val;
+    value->state = state;
+    QAPI_LIST_PREPEND(caps, value);
     qmp_migrate_set_capabilities(caps, &err);
+    qapi_free_MigrationCapabilityStatusList(caps);
 
 end:
-    qapi_free_MigrationCapabilityStatusList(caps);
     hmp_handle_error(mon, err);
 }
 
diff --git a/monitor/misc.c b/monitor/misc.c
index fde6e36a0b..f2ee7cd77a 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -1430,33 +1430,26 @@ FdsetInfoList *qmp_query_fdsets(Error **errp)
 
     QEMU_LOCK_GUARD(&mon_fdsets_lock);
     QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
-        FdsetInfoList *fdset_info = g_malloc0(sizeof(*fdset_info));
-        FdsetFdInfoList *fdsetfd_list = NULL;
+        FdsetInfo *fdset_info = g_malloc0(sizeof(*fdset_info));
 
-        fdset_info->value = g_malloc0(sizeof(*fdset_info->value));
-        fdset_info->value->fdset_id = mon_fdset->id;
+        fdset_info->fdset_id = mon_fdset->id;
 
         QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
-            FdsetFdInfoList *fdsetfd_info;
+            FdsetFdInfo *fdsetfd_info;
 
             fdsetfd_info = g_malloc0(sizeof(*fdsetfd_info));
-            fdsetfd_info->value = g_malloc0(sizeof(*fdsetfd_info->value));
-            fdsetfd_info->value->fd = mon_fdset_fd->fd;
+            fdsetfd_info->fd = mon_fdset_fd->fd;
             if (mon_fdset_fd->opaque) {
-                fdsetfd_info->value->has_opaque = true;
-                fdsetfd_info->value->opaque = g_strdup(mon_fdset_fd->opaque);
+                fdsetfd_info->has_opaque = true;
+                fdsetfd_info->opaque = g_strdup(mon_fdset_fd->opaque);
             } else {
-                fdsetfd_info->value->has_opaque = false;
+                fdsetfd_info->has_opaque = false;
             }
 
-            fdsetfd_info->next = fdsetfd_list;
-            fdsetfd_list = fdsetfd_info;
+            QAPI_LIST_PREPEND(fdset_info->fds, fdsetfd_info);
         }
 
-        fdset_info->value->fds = fdsetfd_list;
-
-        fdset_info->next = fdset_list;
-        fdset_list = fdset_info;
+        QAPI_LIST_PREPEND(fdset_list, fdset_info);
     }
 
     return fdset_list;
diff --git a/monitor/qmp-cmds-control.c b/monitor/qmp-cmds-control.c
index a456762f6a..17514f4959 100644
--- a/monitor/qmp-cmds-control.c
+++ b/monitor/qmp-cmds-control.c
@@ -138,18 +138,18 @@ EventInfoList *qmp_query_events(Error **errp)
      * QAPIEvent_str() and QAPIEvent_lookup[].  When the command goes,
      * they should go, too.
      */
-    EventInfoList *info, *ev_list = NULL;
+    EventInfoList *ev_list = NULL;
     QAPIEvent e;
 
     for (e = 0 ; e < QAPI_EVENT__MAX ; e++) {
         const char *event_name = QAPIEvent_str(e);
+        EventInfo *info;
+
         assert(event_name != NULL);
         info = g_malloc0(sizeof(*info));
-        info->value = g_malloc0(sizeof(*info->value));
-        info->value->name = g_strdup(event_name);
+        info->name = g_strdup(event_name);
 
-        info->next = ev_list;
-        ev_list = info;
+        QAPI_LIST_PREPEND(ev_list, info);
     }
 
     return ev_list;