error: Eliminate error_propagate() with Coccinelle, part 2

When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.  The previous commit did that with a Coccinelle script I
consider fairly trustworthy.  This commit uses the same script with
the matching of return taken out, i.e. we convert

    if (!foo(..., &err)) {
        ...
        error_propagate(errp, err);
        ...
    }

to

    if (!foo(..., errp)) {
        ...
        ...
    }

This is unsound: @err could still be read between afterwards.  I don't
know how to express "no read of @err without an intervening write" in
Coccinelle.  Instead, I manually double-checked for uses of @err.

Suboptimal line breaks tweaked manually.  qdev_realize() simplified
further to placate scripts/checkpatch.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-36-armbru@redhat.com>

1 files changed, 2 insertions, 6 deletions

diff --git a/block/nbd.c b/block/nbd.c
index 1331307ffb..6876da04a7 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -1726,7 +1726,6 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
     SocketAddress *saddr = NULL;
     QDict *addr = NULL;
     Visitor *iv = NULL;
-    Error *local_err = NULL;
 
     qdict_extract_subqdict(options, &addr, "server.");
     if (!qdict_size(addr)) {
@@ -1739,8 +1738,7 @@ static SocketAddress *nbd_config(BDRVNBDState *s, QDict *options,
         goto done;
     }
 
-    if (!visit_type_SocketAddress(iv, NULL, &saddr, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!visit_type_SocketAddress(iv, NULL, &saddr, errp)) {
         goto done;
     }
 
@@ -1835,12 +1833,10 @@ static int nbd_process_options(BlockDriverState *bs, QDict *options,
 {
     BDRVNBDState *s = bs->opaque;
     QemuOpts *opts;
-    Error *local_err = NULL;
     int ret = -EINVAL;
 
     opts = qemu_opts_create(&nbd_runtime_opts, NULL, 0, &error_abort);
-    if (!qemu_opts_absorb_qdict(opts, options, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!qemu_opts_absorb_qdict(opts, options, errp)) {
         goto error;
     }