[RFC v5 049/126] USB (serial adapter): 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 <address@hidden>
Reported-by: Greg Kurz <address@hidden>
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 hw/usb/dev-serial.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
index 45cc74128a..72959b4005 100644
--- a/hw/usb/dev-serial.c
+++ b/hw/usb/dev-serial.c
@@ -484,8 +484,8 @@ static void usb_serial_event(void *opaque, int event)
 
 static void usb_serial_realize(USBDevice *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     USBSerialState *s = USB_SERIAL_DEV(dev);
-    Error *local_err = NULL;
 
     usb_desc_create_serial(dev);
     usb_desc_init(dev);
@@ -496,9 +496,8 @@ static void usb_serial_realize(USBDevice *dev, Error **errp)
         return;
     }
 
-    usb_check_attach(dev, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    usb_check_attach(dev, errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0