* Peter Jones <pjones@xxxxxxxxxx> wrote:
> On Tue, Jun 02, 2015 at 08:45:57AM +0200, Ingo Molnar wrote:
> > @@ -167,7 +167,6 @@ static struct kset *esrt_kset;
> >
> > static int esre_create_sysfs_entry(void *esre, int entry_num)
> > {
> > - int rc = 0;
> > struct esre_entry *entry;
> > char name[20];
> >
> > @@ -180,13 +179,15 @@ static int esre_create_sysfs_entry(void *esre, int entry_num)
> > entry->kobj.kset = esrt_kset;
> >
> > if (esrt->fw_resource_version == 1) {
> > + int rc = 0;
> > +
> > entry->esre.esre1 = esre;
> > rc = kobject_init_and_add(&entry->kobj, &esre1_ktype, NULL,
> > "%s", name);
> > - }
> > - if (rc) {
> > - kfree(entry);
> > - return rc;
> > + if (rc) {
> > + kfree(entry);
> > + return rc;
> > + }
> > }
> >
> > list_add_tail(&entry->list, &entry_list);
> >
> > How can a compiler ever have warned about 'rc' being uninitialized? It's defined
> > straight at function entry, with initialization to 0. It can never be
> > uninitialized.
> >
> > I pulled it, because I agree with the change itself, as it's always better to
> > define and use variables in the narrowest scope possible, but I think it's a
> > cleanup, not a compiler warning fix.
>
> Well, apparently I failed to explain it well - the warning was about
> "esre" rather than "rc". Basically before we were testing the version in
> register_entries() (i.e. this function's caller) and never calling the
> this function if it's not version 1. The compiler didn't figure out
> that when we set "entry->esre.esre1 = esre;", esre can not be null
> because the function wouldn't be called. Adding the explicit check
> on the version here silenced the warning about entry plausibly being
> NULL.
>
> I'm guessing that this is because it's checking that the same
> conditional test is involved - that the initialization is in the same
> "...version == 1" test that the usage is. But that's just a guess.
>
> Would you like another patch to add this email to the commit message, or do you
> want to add it in your tree, or what?
No need, I already pulled, because the changes themselves seemed OK - just wanted
to ask in case there's something subtle going on.
Thanks,
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-efi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
