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>

1 files changed, 4 insertions, 8 deletions

diff --git a/docs/devel/writing-qmp-commands.txt b/docs/devel/writing-qmp-commands.txt
index 28984686c9..258e63bff5 100644
--- a/docs/devel/writing-qmp-commands.txt
+++ b/docs/devel/writing-qmp-commands.txt
@@ -531,15 +531,11 @@ TimerAlarmMethodList *qmp_query_alarm_methods(Error **errp)
     bool current = true;
 
     for (p = alarm_timers; p->name; p++) {
-        TimerAlarmMethodList *info = g_malloc0(sizeof(*info));
-        info->value = g_malloc0(sizeof(*info->value));
-        info->value->method_name = g_strdup(p->name);
-        info->value->current = current;
-
+        TimerAlarmMethod *value = g_malloc0(*value);
+        value->method_name = g_strdup(p->name);
+        value->current = current;
+        QAPI_LIST_PREPEND(method_list, value);
         current = false;
-
-        info->next = method_list;
-        method_list = info;
     }
 
     return method_list;