Re: [PATCH 2/2] xen/tools: remove dead code

["Ariel Otilibili-Anieli" <Ariel.Otilibili-Anieli@eurecom.fr>]

On Tuesday, December 24, 2024 09:43 CET, Jan Beulich <jbeulich@suse.com> wrote:

> On 20.12.2024 17:55, Ariel Otilibili wrote:
> > Default switch case exits directly; these instructions are never reached.
> > 
> > The file was taken from Linux; the copies have diverged a lot since:
> > 
> > ```
> > $ diff -u xen/xen/tools/kconfig/expr.c linux/scripts/kconfig/expr.c | wc -l
> > 984
> > ```
> > 
> > Therefore the change is only applied locally.
> > 
> > Coverity-ID: 1458052
> > Fixes: 8c271b7584 ("build: import Kbuild/Kconfig from Linux 4.3")
> > Signed-off-by: Ariel Otilibili <Ariel.Otilibili-Anieli@eurecom.fr>
> 
> As the title of the commit referenced already clarifies - this is once
> again code we took from elsewhere, so imo wants updating at the origin
> first. Then import that commit into Xen.

Indeed, Jan; thanks for the feedback. I am pushing a new series for this hunk; it was fixed in Linux.
I think in commits dfe8e56fc604 ("kconfig: add fallthrough comments to expr_compare_type()"), & 9ad86d747c46 ("kconfig: remove unreachable printf()").

```
$ diff -u xen/xen/tools/kconfig/expr.c linux/scripts/kconfig/expr.c | sed -ne '/expr_compare_type/,/return 0/{N;p}'
 static int expr_compare_type(enum expr_type t1, enum expr_type t2)
 {
        if (t1 == t2)
@@ -1106,30 +999,27 @@
        case E_GTH:
                if (t2 == E_EQUAL || t2 == E_UNEQUAL)
                        return 1;
+               /* fallthrough */
        case E_EQUAL:
        case E_UNEQUAL:
                if (t2 == E_NOT)
                        return 1;
+               /* fallthrough */
        case E_NOT:
                if (t2 == E_AND)
                        return 1;
+               /* fallthrough */
        case E_AND:
                if (t2 == E_OR)
                        return 1;
-       case E_OR:
-               if (t2 == E_LIST)
-                       return 1;
-       case E_LIST:
-               if (t2 == 0)
-                       return 1;
+               /* fallthrough */
        default:
-               return -1;
+               break;
        }
-       printf("[%dgt%d?]", t1, t2);
        return 0;
 }

$ cd linux/; 
$ git log --oneline -1 --pretty='%h ("%s")'
8155b4ef3466 ("Add linux-next specific files for 20241220")
$ git remote -v 
next    git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git (fetch)
next    git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git (push)

$ cd ../xen/
$ git log --oneline -1 --pretty='%h ("%s")'
6419020270 ("CHANGELOG: Mention LLC coloring feature on Arm")

$ git remote -v 
up      git://xenbits.xen.org/xen.git (fetch)
up      git://xenbits.xen.org/xen.git (push)
```
> 
> Jan