From: "H. Peter Anvin" <hpa@linux.intel.com>
To: "Theodore Ts'o" <tytso@mit.edu>, "H. Peter Anvin" <hpa@zytor.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
greg@kroah.com, w@1wt.eu, ewust@umich.edu, zakir@umich.edu,
mpm@selenic.com, nadiah@cs.ucsd.edu, jhalderm@umich.edu,
tglx@linutronix.de, davem@davemloft.net, mingo@kernel.org,
DJ Johnston <dj.johnston@intel.com>,
stable@vger.kernel.org
Subject: Re: [PATCH RFC] random: Account for entropy loss due to overwrites
Date: Mon, 15 Oct 2012 21:45:23 -0700 [thread overview]
Message-ID: <507CE663.2060502@linux.intel.com> (raw)
In-Reply-To: <20121016040848.GE17446@thunk.org>
On 10/15/2012 09:08 PM, Theodore Ts'o wrote:
> On Sat, Sep 29, 2012 at 12:47:04PM -0700, H. Peter Anvin wrote:
>>> -static struct poolinfo {
>>> +static const struct poolinfo {
>>> + int poolshift; /* log2(POOLBITS) */
>>> int poolwords;
>>> int tap1, tap2, tap3, tap4, tap5;
>
> Poolshift is duplicated information; it's just log2(poolwords) + 5
> (since POOLBITS is poolwords*32).
>
> Granted you don't want to recalculate it every single time you need to
> use it, but perhaps it would be better to add poolshift to struct
> entropy_store, and set it in init_std_data()?
>
Or we could compute poolwords (and poolbits, and poolbytes) from it,
since shifts generally are cheap. I don't strongly care, whatever your
preference is.
-hpa
next prev parent reply other threads:[~2012-10-16 4:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-13 17:26 H. Peter Anvin
2012-08-15 19:30 ` Matt Mackall
2012-08-15 20:37 ` H. Peter Anvin
2012-09-29 19:47 ` H. Peter Anvin
2012-10-16 4:08 ` Theodore Ts'o
2012-10-16 4:45 ` H. Peter Anvin [this message]
2012-10-16 15:53 ` Theodore Ts'o
2012-10-16 16:10 ` H. Peter Anvin
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