Re: [RFC v5 119/126] hw/core/bus.c: introduce ERRP_AUTO_PROPAGATE

[Philippe Mathieu-Daudé]

On 10/11/19 6:05 PM, Vladimir Sementsov-Ogievskiy wrote:

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 <kw...@redhat.com>
Reported-by: Greg Kurz <gr...@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
  hw/core/bus.c | 15 +++++++--------
  1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/hw/core/bus.c b/hw/core/bus.c
index 7f3d2a3dbd..0a1e508963 100644
--- a/hw/core/bus.c
+++ b/hw/core/bus.c
@@ -146,14 +146,14 @@ static bool bus_get_realized(Object *obj, Error **errp)

static void bus_set_realized(Object *obj, bool value, Error **errp)

  {
+    ERRP_AUTO_PROPAGATE();
      BusState *bus = BUS(obj);
      BusClass *bc = BUS_GET_CLASS(bus);
      BusChild *kid;
-    Error *local_err = NULL;

if (value && !bus->realized) {

          if (bc->realize) {
-            bc->realize(bus, &local_err);
+            bc->realize(bus, errp);
          }

/* TODO: recursive realization */

@@ -161,18 +161,17 @@ static void bus_set_realized(Object *obj, bool value, 
Error **errp)
          QTAILQ_FOREACH(kid, &bus->children, sibling) {
              DeviceState *dev = kid->child;
              object_property_set_bool(OBJECT(dev), false, "realized",
-                                     &local_err);
-            if (local_err != NULL) {
+                                     errp);

You can add it at the end of the previous line.

Regardless:
Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>

+            if (*errp) {
                  break;
              }
          }
-        if (bc->unrealize && local_err == NULL) {
-            bc->unrealize(bus, &local_err);
+        if (bc->unrealize && *errp == NULL) {
+            bc->unrealize(bus, errp);
          }
      }

- if (local_err != NULL) {

-        error_propagate(errp, local_err);
+    if (*errp) {
          return;
      }