[RFC v5 058/126] virtio-serial: 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/char/virtio-serial-bus.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index 4e0ed829ae..8ab7f29d0a 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -935,12 +935,12 @@ static void remove_port(VirtIOSerial *vser, uint32_t 
port_id)
 
 static void virtser_port_device_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(dev);
     VirtIOSerialPortClass *vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
     VirtIOSerialBus *bus = VIRTIO_SERIAL_BUS(qdev_get_parent_bus(dev));
     int max_nr_ports;
     bool plugging_port0;
-    Error *err = NULL;
 
     port->vser = bus->vser;
     port->bh = qemu_bh_new(flush_queued_data_bh, port);
@@ -986,9 +986,8 @@ static void virtser_port_device_realize(DeviceState *dev, 
Error **errp)
         return;
     }
 
-    vsc->realize(dev, &err);
-    if (err != NULL) {
-        error_propagate(errp, err);
+    vsc->realize(dev, errp);
+    if (*errp) {
         return;
     }
 
-- 
2.21.0