[RFC v5 064/126] fw_cfg: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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/nvram/fw_cfg.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 7dc3ac378e..e10687c876 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -1104,12 +1104,11 @@ static Property fw_cfg_io_properties[] = {
 
 static void fw_cfg_io_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     FWCfgIoState *s = FW_CFG_IO(dev);
-    Error *local_err = NULL;
 
-    fw_cfg_file_slots_allocate(FW_CFG(s), &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    fw_cfg_file_slots_allocate(FW_CFG(s), errp);
+    if (*errp) {
         return;
     }
 
@@ -1155,14 +1154,13 @@ static Property fw_cfg_mem_properties[] = {
 
 static void fw_cfg_mem_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     FWCfgMemState *s = FW_CFG_MEM(dev);
     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
     const MemoryRegionOps *data_ops = &fw_cfg_data_mem_ops;
-    Error *local_err = NULL;
 
-    fw_cfg_file_slots_allocate(FW_CFG(s), &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    fw_cfg_file_slots_allocate(FW_CFG(s), errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0