linux-kernel - Re: [PATCH v1 08/12] i2c: isch: Use read_poll

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

Message-ID: <45bkfzv7peff2gfdf4h2ot6z4fv3uxcmiljsnlhyy5ltzhehca@bsa5ojshvlcb>
Date: Thu, 12 Sep 2024 18:43:21 +0200
From: Andi Shyti <andi.shyti@...nel.org>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org, Jean Delvare <jdelvare@...e.com>
Subject: Re: [PATCH v1 08/12] i2c: isch: Use read_poll_timeout()

On Thu, Sep 12, 2024 at 07:06:19PM GMT, Andy Shevchenko wrote:
> On Thu, Sep 12, 2024 at 6:55 PM Andi Shyti <andi.shyti@...nel.org> wrote:
> > On Thu, Sep 12, 2024 at 06:35:46PM GMT, Andy Shevchenko wrote:
> > > Thu, Sep 12, 2024 at 09:29:38AM +0200, Andi Shyti kirjoitti:
> 
> ...
> 
> > > > > -         sch_io_wr8(priv, SMBHSTSTS, temp);
> > > > > +         sch_io_wr8(priv, SMBHSTSTS, temp & 0x0f);
> > > >
> > > > there is still a dev_dbg() using temp. To be on the safe side, do
> > > > we want to do a "temp &= 0x0f" after the read_poll_timeout?
> > >
> > > Isn't it even better that we have more information in the debug output?
> >
> > I think not, because:
> >
> >  1. It's information that we don't need, and we intentionally
> >     discard in every check. If we print a value we ignore, we
> >     risk providing incorrect information.
> >
> >  2. It’s more future-proof. In future development, cleanups,
> >     refactorings, or copy-paste, temp can be used as is
> >     without needing to continuously & it with 0xf. This
> >     avoids unnecessary operations being repeated later on.
> >
> >  3. It maintains the original design.
> 
> Okay, but where do you see this debug message? I looked again into the
> code and do not see that _this_ value of temp is used in the
> messaging. What did I miss?

Indeed nowhere :-)
'temp' is re-read right after and &-ed with 0x0f.
Nevermind!

Andi