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>

1 files changed, 2 insertions, 5 deletions

diff --git a/block/nfs.c b/block/nfs.c
index b1718d125a..61a249a9fc 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -563,18 +563,15 @@ static BlockdevOptionsNfs *nfs_options_qdict_to_qapi(QDict *options,
     BlockdevOptionsNfs *opts = NULL;
     Visitor *v;
     const QDictEntry *e;
-    Error *local_err = NULL;
 
     v = qobject_input_visitor_new_flat_confused(options, errp);
     if (!v) {
         return NULL;
     }
 
-    visit_type_BlockdevOptionsNfs(v, NULL, &opts, &local_err);
+    visit_type_BlockdevOptionsNfs(v, NULL, &opts, errp);
     visit_free(v);
-
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (!opts) {
         return NULL;
     }