From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sergey Senozhatsky <sergey.senozhatsky.work-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH] mm: Use fallthrough;
Date: Mon, 9 Mar 2020 15:48:06 +0900
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To: Joe Perches <joe-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Vladimir Davydov <vdavydov.dev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Hugh Dickins <hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>, Minchan Kim <minchan-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Nitin Gupta <ngupta-KNmc09w0p+Ednm+yROfE0A@public.gmane.org>, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Sergey Senozhatsky <sergey.senozhatsky.work-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

On (20/03/09 15:20), Sergey Senozhatsky wrote:
[..]
> > <shrug, maybe>  I've no real opinion about that necessity.
> > 
> > fallthrough commments are relatively rarely used as a
> > separating element between case labels.
> > 
> > It's by far most common to just have consecutive case labels
> > without any other content.
> > 
> > It's somewhere between 500:1 to 1000:1 in the kernel.
> 
> I thought that those labels were used by some static code analysis
> tools, so that the removal of some labels raised questions. But I
> don't think I have opinions otherwise.

... I guess GCC counts as a static code analysis tool :)

Looking at previous commits, people wanted to have proper 'fall through'


    Replace "fallthru" with a proper "fall through" annotation.
    This fix is part of the ongoing efforts to enabling
    -Wimplicit-fallthrough

---

-       case ZPOOL_MM_RW: /* fallthru */
+       case ZPOOL_MM_RW: /* fall through */

---


> Consecutive case labels do not need an interleaving fallthrough;

I suppose this means that GCC -Wimplicit-fallthrough handles it?

	-ss