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 a8aa94b "qga: update
schema for guest-get-disks 'dependents' field" and commit a10b453
"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>

block/gluster.c

@@ -359,8 +359,8 @@ static int qemu_gluster_parse_uri(BlockdevOptionsGluster *gconf,
         return -EINVAL;
     }
 
-    gconf->server = g_new0(SocketAddressList, 1);
-    gconf->server->value = gsconf = g_new0(SocketAddress, 1);
+    gsconf = g_new0(SocketAddress, 1);
+    QAPI_LIST_PREPEND(gconf->server, gsconf);
 
     /* transport */
     if (!uri->scheme || !strcmp(uri->scheme, "gluster")) {

block/qapi.c

@@ -486,12 +486,7 @@ static void bdrv_query_blk_stats(BlockDeviceStats *ds, BlockBackend *blk)
     ds->account_failed = stats->account_failed;
 
     while ((ts = block_acct_interval_next(stats, ts))) {
-        BlockDeviceTimedStatsList *timed_stats =
-            g_malloc0(sizeof(*timed_stats));
         BlockDeviceTimedStats *dev_stats = g_malloc0(sizeof(*dev_stats));
-        timed_stats->next = ds->timed_stats;
-        timed_stats->value = dev_stats;
-        ds->timed_stats = timed_stats;
 
         TimedAverage *rd = &ts->latency[BLOCK_ACCT_READ];
         TimedAverage *wr = &ts->latency[BLOCK_ACCT_WRITE];
@@ -515,6 +510,8 @@ static void bdrv_query_blk_stats(BlockDeviceStats *ds, BlockBackend *blk)
             block_acct_queue_depth(ts, BLOCK_ACCT_READ);
         dev_stats->avg_wr_queue_depth =
             block_acct_queue_depth(ts, BLOCK_ACCT_WRITE);
+
+        QAPI_LIST_PREPEND(ds->timed_stats, dev_stats);
     }
 
     bdrv_latency_histogram_stats(&stats->latency_histogram[BLOCK_ACCT_READ],

chardev/char.c

@@ -776,15 +776,13 @@ static int qmp_query_chardev_foreach(Object *obj, void *data)
 {
     Chardev *chr = CHARDEV(obj);
     ChardevInfoList **list = data;
-    ChardevInfoList *info = g_malloc0(sizeof(*info));
+    ChardevInfo *value = g_malloc0(sizeof(*value));
 
-    info->value = g_malloc0(sizeof(*info->value));
-    info->value->label = g_strdup(chr->label);
-    info->value->filename = g_strdup(chr->filename);
-    info->value->frontend_open = chr->be && chr->be->fe_open;
+    value->label = g_strdup(chr->label);
+    value->filename = g_strdup(chr->filename);
+    value->frontend_open = chr->be && chr->be->fe_open;
 
-    info->next = *list;
-    *list = info;
+    QAPI_LIST_PREPEND(*list, value);
 
     return 0;
 }
@@ -803,12 +801,10 @@ static void
 qmp_prepend_backend(const char *name, void *opaque)
 {
     ChardevBackendInfoList **list = opaque;
-    ChardevBackendInfoList *info = g_malloc0(sizeof(*info));
+    ChardevBackendInfo *value = g_new0(ChardevBackendInfo, 1);
 
-    info->value = g_malloc0(sizeof(*info->value));
-    info->value->name = g_strdup(name);
-    info->next = *list;
-    *list = info;
+    value->name = g_strdup(name);
+    QAPI_LIST_PREPEND(*list, value);
 }
 
 ChardevBackendInfoList *qmp_query_chardev_backends(Error **errp)

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;

hw/core/machine-qmp-cmds.c

@@ -215,7 +215,6 @@ MachineInfoList *qmp_query_machines(Error **errp)
 
     for (el = machines; el; el = el->next) {
         MachineClass *mc = el->data;
-        MachineInfoList *entry;
         MachineInfo *info;
 
         info = g_malloc0(sizeof(*info));
@@ -243,10 +242,7 @@ MachineInfoList *qmp_query_machines(Error **errp)
             info->has_default_ram_id = true;
         }
 
-        entry = g_malloc0(sizeof(*entry));
-        entry->value = info;
-        entry->next = mach_list;
-        mach_list = entry;
+        QAPI_LIST_PREPEND(mach_list, info);
     }
 
     g_slist_free(machines);

hw/core/machine.c

@@ -504,11 +504,7 @@ static void machine_set_nvdimm_persistence(Object *obj, const char *value,
 
 void machine_class_allow_dynamic_sysbus_dev(MachineClass *mc, const char *type)
 {
-    strList *item = g_new0(strList, 1);
-
-    item->value = g_strdup(type);
-    item->next = mc->allowed_dynamic_sysbus_devices;
-    mc->allowed_dynamic_sysbus_devices = item;
+    QAPI_LIST_PREPEND(mc->allowed_dynamic_sysbus_devices, g_strdup(type));
 }
 
 static void validate_sysbus_device(SysBusDevice *sbdev, void *opaque)
@@ -569,7 +565,6 @@ HotpluggableCPUList *machine_query_hotpluggable_cpus(MachineState *machine)
 
     for (i = 0; i < machine->possible_cpus->len; i++) {
         Object *cpu;
-        HotpluggableCPUList *list_item = g_new0(typeof(*list_item), 1);
         HotpluggableCPU *cpu_item = g_new0(typeof(*cpu_item), 1);
 
         cpu_item->type = g_strdup(machine->possible_cpus->cpus[i].type);
@@ -582,9 +577,7 @@ HotpluggableCPUList *machine_query_hotpluggable_cpus(MachineState *machine)
             cpu_item->has_qom_path = true;
             cpu_item->qom_path = object_get_canonical_path(cpu);
         }
-        list_item->value = cpu_item;
-        list_item->next = head;
-        head = list_item;
+        QAPI_LIST_PREPEND(head, cpu_item);
     }
     return head;
 }

hw/net/rocker/rocker_of_dpa.c

@@ -2296,7 +2296,6 @@ static void of_dpa_flow_fill(void *cookie, void *value, void *user_data)
     struct of_dpa_flow_key *key = &flow->key;
     struct of_dpa_flow_key *mask = &flow->mask;
     struct of_dpa_flow_fill_context *flow_context = user_data;
-    RockerOfDpaFlowList *new;
     RockerOfDpaFlow *nflow;
     RockerOfDpaFlowKey *nkey;
     RockerOfDpaFlowMask *nmask;
@@ -2307,8 +2306,7 @@ static void of_dpa_flow_fill(void *cookie, void *value, void *user_data)
         return;
     }
 
-    new = g_malloc0(sizeof(*new));
-    nflow = new->value = g_malloc0(sizeof(*nflow));
+    nflow = g_malloc0(sizeof(*nflow));
     nkey = nflow->key = g_malloc0(sizeof(*nkey));
     nmask = nflow->mask = g_malloc0(sizeof(*nmask));
     naction = nflow->action = g_malloc0(sizeof(*naction));
@@ -2424,8 +2422,7 @@ static void of_dpa_flow_fill(void *cookie, void *value, void *user_data)
         naction->new_vlan_id = flow->action.apply.new_vlan_id;
     }
 
-    new->next = flow_context->list;
-    flow_context->list = new;
+    QAPI_LIST_PREPEND(flow_context->list, nflow);
 }
 
 RockerOfDpaFlowList *qmp_query_rocker_of_dpa_flows(const char *name,
@@ -2469,18 +2466,15 @@ static void of_dpa_group_fill(void *key, void *value, void *user_data)
 {
     struct of_dpa_group *group = value;
     struct of_dpa_group_fill_context *flow_context = user_data;
-    RockerOfDpaGroupList *new;
     RockerOfDpaGroup *ngroup;
-    struct uint32List *id;
     int i;
 
     if (flow_context->type != 9 &&
         flow_context->type != ROCKER_GROUP_TYPE_GET(group->id)) {
         return;
     }
 
-    new = g_malloc0(sizeof(*new));
-    ngroup = new->value = g_malloc0(sizeof(*ngroup));
+    ngroup = g_malloc0(sizeof(*ngroup));
 
     ngroup->id = group->id;
 
@@ -2525,10 +2519,7 @@ static void of_dpa_group_fill(void *key, void *value, void *user_data)
         ngroup->index = ROCKER_GROUP_INDEX_GET(group->id);
         for (i = 0; i < group->l2_flood.group_count; i++) {
             ngroup->has_group_ids = true;
-            id = g_malloc0(sizeof(*id));
-            id->value = group->l2_flood.group_ids[i];
-            id->next = ngroup->group_ids;
-            ngroup->group_ids = id;
+            QAPI_LIST_PREPEND(ngroup->group_ids, group->l2_flood.group_ids[i]);
         }
         break;
     case ROCKER_OF_DPA_GROUP_TYPE_L3_UCAST:
@@ -2557,8 +2548,7 @@ static void of_dpa_group_fill(void *key, void *value, void *user_data)
         break;
     }
 
-    new->next = flow_context->list;
-    flow_context->list = new;
+    QAPI_LIST_PREPEND(flow_context->list, ngroup);
 }
 
 RockerOfDpaGroupList *qmp_query_rocker_of_dpa_groups(const char *name,

hw/net/virtio-net.c

@@ -437,17 +437,14 @@ static void rxfilter_notify(NetClientState *nc)
 
 static intList *get_vlan_table(VirtIONet *n)
 {
-    intList *list, *entry;
+    intList *list;
     int i, j;
 
     list = NULL;
     for (i = 0; i < MAX_VLAN >> 5; i++) {
         for (j = 0; n->vlans[i] && j <= 0x1f; j++) {
             if (n->vlans[i] & (1U << j)) {
-                entry = g_malloc0(sizeof(*entry));
-                entry->value = (i << 5) + j;
-                entry->next = list;
-                list = entry;
+                QAPI_LIST_PREPEND(list, (i << 5) + j);
             }
         }
     }
@@ -460,7 +457,7 @@ static RxFilterInfo *virtio_net_query_rxfilter(NetClientState *nc)
     VirtIONet *n = qemu_get_nic_opaque(nc);
     VirtIODevice *vdev = VIRTIO_DEVICE(n);
     RxFilterInfo *info;
-    strList *str_list, *entry;
+    strList *str_list;
     int i;
 
     info = g_malloc0(sizeof(*info));
@@ -491,19 +488,15 @@ static RxFilterInfo *virtio_net_query_rxfilter(NetClientState *nc)
 
     str_list = NULL;
     for (i = 0; i < n->mac_table.first_multi; i++) {
-        entry = g_malloc0(sizeof(*entry));
-        entry->value = qemu_mac_strdup_printf(n->mac_table.macs + i * ETH_ALEN);
-        entry->next = str_list;
-        str_list = entry;
+        QAPI_LIST_PREPEND(str_list,
+                      qemu_mac_strdup_printf(n->mac_table.macs + i * ETH_ALEN));
     }
     info->unicast_table = str_list;
 
     str_list = NULL;
     for (i = n->mac_table.first_multi; i < n->mac_table.in_use; i++) {
-        entry = g_malloc0(sizeof(*entry));
-        entry->value = qemu_mac_strdup_printf(n->mac_table.macs + i * ETH_ALEN);
-        entry->next = str_list;
-        str_list = entry;
+        QAPI_LIST_PREPEND(str_list,
+                      qemu_mac_strdup_printf(n->mac_table.macs + i * ETH_ALEN));
     }
     info->multicast_table = str_list;
     info->vlan_table = get_vlan_table(n);

migration/migration.c

@@ -406,12 +406,9 @@ int migration_incoming_enable_colo(void)
 void migrate_add_address(SocketAddress *address)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
-    SocketAddressList *addrs;
 
-    addrs = g_new0(SocketAddressList, 1);
-    addrs->next = mis->socket_address_list;
-    mis->socket_address_list = addrs;
-    addrs->value = QAPI_CLONE(SocketAddress, address);
+    QAPI_LIST_PREPEND(mis->socket_address_list,
+                      QAPI_CLONE(SocketAddress, address));
 }
 
 static void qemu_start_incoming_migration(const char *uri, Error **errp)

migration/postcopy-ram.c

@@ -145,14 +145,11 @@ static struct PostcopyBlocktimeContext *blocktime_context_new(void)
 static uint32List *get_vcpu_blocktime_list(PostcopyBlocktimeContext *ctx)
 {
     MachineState *ms = MACHINE(qdev_get_machine());
-    uint32List *list = NULL, *entry = NULL;
+    uint32List *list = NULL;
     int i;
 
     for (i = ms->smp.cpus - 1; i >= 0; i--) {
-        entry = g_new0(uint32List, 1);
-        entry->value = ctx->vcpu_blocktime[i];
-        entry->next = list;
-        list = entry;
+        QAPI_LIST_PREPEND(list, ctx->vcpu_blocktime[i]);
     }
 
     return list;

monitor/hmp-cmds.c

@@ -1255,22 +1255,23 @@ 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);
     if (val < 0) {
         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);
 }
 

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;

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;