qapi: Smooth another visitor error checking pattern

Convert

    visit_type_FOO(v, ..., &ptr, &err);
    ...
    if (err) {
        ...
    }

to

    visit_type_FOO(v, ..., &ptr, errp);
    ...
    if (!ptr) {
        ...
    }

for functions that set @ptr to non-null / null on success / error.

Eliminate error_propagate() that are now unnecessary.  Delete @err
that are now unused.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-40-armbru@redhat.com>

3 files changed, 7 insertions, 11 deletions

diff --git a/hw/acpi/core.c b/hw/acpi/core.c
index 8b240c3..f6d9ec4 100644
--- a/hw/acpi/core.c
+++ b/hw/acpi/core.c
@@ -239,7 +239,6 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen,
 void acpi_table_add(const QemuOpts *opts, Error **errp)
 {
     AcpiTableOptions *hdrs = NULL;
-    Error *err = NULL;
     char **pathnames = NULL;
     char **cur;
     size_t bloblen = 0;
@@ -249,11 +248,11 @@ void acpi_table_add(const QemuOpts *opts, Error **errp)
         Visitor *v;
 
         v = opts_visitor_new(opts);
-        visit_type_AcpiTableOptions(v, NULL, &hdrs, &err);
+        visit_type_AcpiTableOptions(v, NULL, &hdrs, errp);
         visit_free(v);
     }
 
-    if (err) {
+    if (!hdrs) {
         goto out;
     }
     if (hdrs->has_file == hdrs->has_data) {
diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index 96c6c00..a775fba 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -682,11 +682,9 @@ static char *xen_block_blockdev_add(const char *id, QDict *qdict,
     trace_xen_block_blockdev_add(node_name);
 
     v = qobject_input_visitor_new(QOBJECT(qdict));
-    visit_type_BlockdevOptions(v, NULL, &options, &local_err);
+    visit_type_BlockdevOptions(v, NULL, &options, errp);
     visit_free(v);
-
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (!options) {
         goto fail;
     }
 
diff --git a/hw/core/numa.c b/hw/core/numa.c
index 1b3267a..d1a94a1 100644
--- a/hw/core/numa.c
+++ b/hw/core/numa.c
@@ -516,10 +516,10 @@ static int parse_numa(void *opaque, QemuOpts *opts, Error **errp)
     Error *err = NULL;
     Visitor *v = opts_visitor_new(opts);
 
-    visit_type_NumaOptions(v, NULL, &object, &err);
+    visit_type_NumaOptions(v, NULL, &object, errp);
     visit_free(v);
-    if (err) {
-        goto end;
+    if (!object) {
+        return -1;
     }
 
     /* Fix up legacy suffix-less format */
@@ -530,7 +530,6 @@ static int parse_numa(void *opaque, QemuOpts *opts, Error **errp)
 
     set_numa_options(ms, object, &err);
 
-end:
     qapi_free_NumaOptions(object);
     if (err) {
         error_propagate(errp, err);