Re: [RFC v5 086/126] TPM: introduce ERRP_AUTO_PROPAGATE

[Stefan Berger]

On 10/11/19 12:05 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>

Reviewed-by: Stefan Berger <stef...@linux.ibm.com>

---
  hw/tpm/tpm_util.c | 7 +++----
  tpm.c             | 7 +++----
  2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/hw/tpm/tpm_util.c b/hw/tpm/tpm_util.c
index 62b091f0c0..b0657bbbf2 100644
--- a/hw/tpm/tpm_util.c
+++ b/hw/tpm/tpm_util.c
@@ -47,8 +47,8 @@ static void get_tpm(Object *obj, Visitor *v, const char 
*name, void *opaque,
  static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
                      Error **errp)
  {
+    ERRP_AUTO_PROPAGATE();
      DeviceState *dev = DEVICE(obj);
-    Error *local_err = NULL;
      Property *prop = opaque;
      TPMBackend *s, **be = qdev_get_prop_ptr(dev, prop);
      char *str;
@@ -58,9 +58,8 @@ static void set_tpm(Object *obj, Visitor *v, const char 
*name, void *opaque,
          return;
      }

- visit_type_str(v, name, &str, &local_err);

-    if (local_err) {
-        error_propagate(errp, local_err);
+    visit_type_str(v, name, &str, errp);
+    if (*errp) {
          return;
      }

diff --git a/tpm.c b/tpm.c

index 9c9e20bbb7..359ebb7f68 100644
--- a/tpm.c
+++ b/tpm.c
@@ -81,11 +81,11 @@ TPMBackend *qemu_find_tpm_be(const char *id)

static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, Error **errp)

  {
+    ERRP_AUTO_PROPAGATE();
      const char *value;
      const char *id;
      const TPMBackendClass *be;
      TPMBackend *drv;
-    Error *local_err = NULL;
      int i;

if (!QLIST_EMPTY(&tpm_backends)) {

@@ -116,9 +116,8 @@ static int tpm_init_tpmdev(void *dummy, QemuOpts *opts, 
Error **errp)
      }

/* validate backend specific opts */

-    qemu_opts_validate(opts, be->opts, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    qemu_opts_validate(opts, be->opts, errp);
+    if (*errp) {
          return 1;
      }