linux-kernel - Re: [PATCH] docs/core-api: Fix circular buffer examples

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <8723a37f-0a04-4e46-80a1-7bb817ecae03@paulmck-laptop>
Date: Wed, 23 Jul 2025 13:47:39 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: Akira Yokosawa <akiyks@...il.com>
Cc: carlos.bilbao@...nel.org, bilbao@...edu, corbet@....net,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	David Howells <dhowells@...hat.com>
Subject: Re: [PATCH] docs/core-api: Fix circular buffer examples

On Mon, Jul 21, 2025 at 11:47:25AM +0900, Akira Yokosawa wrote:
> +CC David and Paul, who are the authors of this doc.
> 
> On Sun, 20 Jul 2025 11:02:43 -0500, Carlos Bilbao wrote:
> > From: Carlos Bilbao <carlos.bilbao@...nel.org>
> > 
> > Fix circular buffer usage in producer/consumer examples in
> > circular-buffers.rst. They incorrectly access items using buffer[head] and
> > buffer[tail], as if buffer was a flat array; but the examples also use
> > buffer->head and buffer->tail, so it's a struct. Use buffer->vals[head] and
> > buffer->vals[tail] instead to match the intended layout.>
> > 
> > Signed-off-by: Carlos Bilbao <carlos.bilbao@...nel.org>

Hello, Carlos, and thank you for your attention to detail!

This one could likely use more help, as the last substantive change was
more than ten years ago.

But are you referring to a particular use of CIRC_SPACE() and CIRC_CNT()
for this change?  If so, could you please identify it in the commit log?

							Thanx, Paul

> > ---
> >  Documentation/core-api/circular-buffers.rst | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/Documentation/core-api/circular-buffers.rst b/Documentation/core-api/circular-buffers.rst
> > index 50966f66e398..b697915a2bd0 100644
> > --- a/Documentation/core-api/circular-buffers.rst
> > +++ b/Documentation/core-api/circular-buffers.rst
> > @@ -161,7 +161,7 @@ The producer will look something like this::
> >  
> >  	if (CIRC_SPACE(head, tail, buffer->size) >= 1) {
> >  		/* insert one item into the buffer */
> > -		struct item *item = buffer[head];
> > +		struct item *item = buffer->vals[head];
> >  
> >  		produce_item(item);
> >  
> > @@ -203,7 +203,7 @@ The consumer will look something like this::
> >  	if (CIRC_CNT(head, tail, buffer->size) >= 1) {
> >  
> >  		/* extract one item from the buffer */
> > -		struct item *item = buffer[tail];
> > +		struct item *item = buffer->vals[tail];
> >  
> >  		consume_item(item);
> >  
> > -- 
> > 2.43.0
> 
>         Thanks, Akira
>