If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and than propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatel, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit (together with its neighbors) was generated by

for f in $(git grep -l errp \*.[ch]); do \
    spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
    --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
done;

then fix a bit of compilation problems: coccinelle for some reason
leaves several
f() {
    ...
    goto out;
    ...
    out:
}
patterns, with "out:" at function end.

then
./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 hw/cpu/core.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/hw/cpu/core.c b/hw/cpu/core.c
index 9874c5c870..9620bd7939 100644
--- a/hw/cpu/core.c
+++ b/hw/cpu/core.c
@@ -27,13 +27,12 @@ static void core_prop_get_core_id(Object *obj, Visitor *v, const char *name,
 static void core_prop_set_core_id(Object *obj, Visitor *v, const char *name,
                                   void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     CPUCore *core = CPU_CORE(obj);
-    Error *local_err = NULL;
     int64_t value;
 
-    visit_type_int(v, name, &value, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_int(v, name, &value, errp);
+    if (*errp) {
         return;
     }
 
@@ -57,13 +56,12 @@ static void core_prop_get_nr_threads(Object *obj, Visitor *v, const char *name,
 static void core_prop_set_nr_threads(Object *obj, Visitor *v, const char *name,
                                      void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     CPUCore *core = CPU_CORE(obj);
-    Error *local_err = NULL;
     int64_t value;
 
-    visit_type_int(v, name, &value, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_int(v, name, &value, errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0