fw_cfg: Use ERRP_GUARD()

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

If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_GUARD() macro.
Otherwise, this info will not be added when errp == &error_fatal
(the program will exit prior to the error_append_hint() or
error_prepend() call).  No such cases are being fixed here.

This commit is generated by command

    sed -n '/^Firmware configuration (fw_cfg)$/,/^$/{s/^F: //p}' \
        MAINTAINERS | \
    xargs git ls-files | grep '\.[hc]$' | \
    xargs spatch \
        --sp-file scripts/coccinelle/errp-guard.cocci \
        --macro-file scripts/cocci-macro-file.h \
        --in-place --no-show-diff --max-width 80

Reported-by: Kevin Wolf <[email protected]>
Reported-by: Greg Kurz <[email protected]>
Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <[email protected]>
Message-Id: <[email protected]>
[ERRP_AUTO_PROPAGATE() renamed to ERRP_GUARD(), and
auto-propagated-errp.cocci to errp-guard.cocci.  Commit message
tweaked again.  Coccinelle script rerun for commit 3203148
"hw/nvram/fw_cfg: Add the FW_CFG_DATA_GENERATOR interface"]

Author: Vladimir Sementsov-Ogievskiy

hw/nvram/fw_cfg.c

@@ -1035,8 +1035,8 @@ void *fw_cfg_modify_file(FWCfgState *s, const char *filename,
 void fw_cfg_add_from_generator(FWCfgState *s, const char *filename,
                                const char *gen_id, Error **errp)
 {
+    ERRP_GUARD();
     FWCfgDataGeneratorClass *klass;
-    Error *local_err = NULL;
     GByteArray *array;
     Object *obj;
     gsize size;
@@ -1052,9 +1052,8 @@ void fw_cfg_add_from_generator(FWCfgState *s, const char *filename,
         return;
     }
     klass = FW_CFG_DATA_GENERATOR_GET_CLASS(obj);
-    array = klass->get_data(obj, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    array = klass->get_data(obj, errp);
+    if (*errp) {
         return;
     }
     size = array->len;
@@ -1260,12 +1259,11 @@ static Property fw_cfg_io_properties[] = {
 
 static void fw_cfg_io_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_GUARD();
     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;
     }
 
@@ -1311,14 +1309,13 @@ static Property fw_cfg_mem_properties[] = {
 
 static void fw_cfg_mem_realize(DeviceState *dev, Error **errp)
 {
+    ERRP_GUARD();
     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;
     }