netdev - Re: [PATCH net-next] net: replace macros net_random and net

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Message-ID: <52D192FD.90606@redhat.com>
Date:	Sat, 11 Jan 2014 19:52:45 +0100
From:	Daniel Borkmann <dborkman@...hat.com>
To:	Hannes Frederic Sowa <hannes@...essinduktion.org>
CC:	Joe Perches <joe@...ches.com>,
	Aruna-Hewapathirane <aruna.hewapathirane@...il.com>,
	netdev@...r.kernel.org
Subject: Re: [PATCH net-next] net: replace macros net_random and net_srandom
 with direct calls to prandom

On 01/11/2014 07:00 PM, Hannes Frederic Sowa wrote:
> On Sat, Jan 11, 2014 at 09:52:37AM -0800, Joe Perches wrote:
>> On Sat, 2014-01-11 at 07:15 -0500, Aruna-Hewapathirane wrote:
>>> This patch removes the net_random and net_srandom macros and replaces
>>> them with direct calls to the prandom ones. As new commits only seem to
>>> use prandom_u32 there is no use to keep them around.
>>> This change makes it easier to grep for users of prandom_u32.
>>
>> Seems sensible.
>>
>> Also, there may be some value in a future patch
>> to use reciprocal_divide in a few places
>>
>>> diff --git a/net/802/garp.c b/net/802/garp.c
>>> @@ -397,7 +397,7 @@ static void garp_join_timer_arm(struct garp_applicant *app)
>>>   {
>>>   	unsigned long delay;
>>>
>>> -	delay = (u64)msecs_to_jiffies(garp_join_time) * net_random() >> 32;
>>> +	delay = (u64)msecs_to_jiffies(garp_join_time) * prandom_u32() >> 32;
>>
>> reciprocal_divide()
>
> Does reciprocal_divide() make sense without reciprocal_value() from a
> stylish point of view?

No. ;-)

There was already some work, but I didn't have time to finish it:

http://www.spinics.net/lists/netdev/msg249395.html

Maybe it's time that we should revisit that.

> I wouldn't do that just because it expands into the same code.
>
> Greetings,
>
>    Hannes
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