From: Ryan Mallon <rmallon@gmail.com>
To: Jesper Juhl <jj@chaosbits.net>
Cc: "David S. Miller" <davem@davemloft.net>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Eric Dumazet <eric.dumazet@gmail.com>,
Changli Gao <xiaosuo@gmail.com>,
Ben Greear <greearb@candelatech.com>,
Chetan Loke <loke.chetan@gmail.com>,
waltje@uWalt.NL.Mugnet.ORG, gw4pts@gw4pts.ampr.org,
waltje@linux.com, ross.biro@gmail.com, alan@linux.intel.com
Subject: Re: [PATCH] net/packet: remove dead code and unneeded variable from prb_setup_retire_blk_timer()
Date: Tue, 15 Nov 2011 10:38:06 +1100 [thread overview]
Message-ID: <4EC1A65E.5040607@gmail.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1111150034120.9919@swampdragon.chaosbits.net>
On 15/11/11 10:37, Jesper Juhl wrote:
> On Mon, 14 Nov 2011, Ryan Mallon wrote:
>
>> On 14/11/11 08:55, Jesper Juhl wrote:
>>
>>> We test for 'tx_ring' being != zero and BUG() if that's the case. So after
>>> that check there is no way that 'tx_ring' could be anything _but_ zero, so
>>> testing it again is just dead code. Once that dead code is removed, the
>>> 'pkc' local variable becomes entirely redundant, so remove that as well.
>>
>>
>> What if CONFIG_BUG=n?
>>
>
> Arrgh, I didn't consider that (should have, but didn't).. In that case
> we'll have
> #define BUG() do {} while(0)
> which is not going to work all that peachy with my change...
>
> David: You may want to pass on this one. I obviously didn't think it
> through properly - sorry :-(
>
It's something I've never been entirely clear on. How are you meant to
handle something which really is a fatal bug if CONFIG_BUG=n?
I think there are several places in the kernel where the expectation is
that BUG() causes a panic that probably don't behave nicely at all
(though I guess that might be the expected behaviour) if CONFIG_BUG=n.
~Ryan
next prev parent reply other threads:[~2011-11-14 23:38 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-13 21:55 [PATCH] net/packet: remove dead code and unneeded variable from prb_setup_retire_blk_timer() Jesper Juhl
2011-11-14 5:09 ` David Miller
2011-11-14 5:42 ` Ryan Mallon
2011-11-14 23:37 ` Jesper Juhl
2011-11-14 23:38 ` Ryan Mallon [this message]
2011-11-14 23:48 ` Jesper Juhl
2011-11-15 0:00 ` Ryan Mallon
2011-11-14 23:43 ` David Miller
2011-11-14 23:51 ` Jesper Juhl
2011-11-14 23:47 ` David Miller
2011-11-15 0:08 ` Jesper Juhl
2011-11-14 15:54 ` chetan loke
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