[cocci] Checking addition of local error code checks

[cocci] Checking addition of local error code checks

[Markus Elfring]

Hello,

I applied the following SmPL script also together with the software
combination “Coccinelle 1.1.1-00628-gd7ca09d1” on a known source file.


@addition@
@@
+{
+int rc =
 fb_alloc_cmap(...);
+if (rc)
+   return rc;
+}


See also:
https://elixir.bootlin.com/linux/v6.7-rc8/source/drivers/video/fbdev/atafb.c#L2988
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/video/fbdev/atafb.c?id=425562be861b46ba8dac78e3927c1cbff5fbb514#n2988


Test result:
Markus_Elfring@Sonne:…/Projekte/Linux/next-analyses> spatch …/Projekte/Coccinelle/janitor/return_error_code_for_fb_alloc_cmap_call_failure.cocci drivers/video/fbdev/atafb.c
…
@@ -3126,7 +3126,11 @@ static int __init atafb_probe(struct pla

        atafb_set_disp(&fb_info);

-       fb_alloc_cmap(&(fb_info.cmap), 1 << fb_info.var.bits_per_pixel, 0);
+       {
+               int rc =fb_alloc_cmap(&(fb_info.cmap), 1 << fb_info.var.bits_per_pixel, 0);
+               if (rc)
+                       return rc;
+       }
…


Such diff output indicates opportunities for pretty-printing improvements.

* Additional space character for variable initialisation

* Line length limit


Regards,
Markus

Re: [cocci] [RFC] fbdev: Completing error handling for fb_alloc_cmap() calls

[Markus Elfring]

> @addition@
> @@
> +{
> +int rc =
>  fb_alloc_cmap(...);
> +if (rc)
> +   return rc;
> +}

How do you think about to apply this script for the semantic patch language
so that remaining update candidates will be found?


See also:
Clarification approach “Checking addition of local error code checks”
https://lore.kernel.org/cocci/913bb6fa-c168-46f7-ba39-5fdaae586b6e@web.de/
https://sympa.inria.fr/sympa/arc/cocci/2024-01/msg00000.html


Do you find further change possibilities still relevant for 23 source files?

Regards,
Markus