Re: [PATCH for-4.5 7/8] xen/irq: Handle multiple action per IRQ

From: Julien Grall <julien.grall@linaro.org>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: xen-devel@lists.xenproject.org, tim@xen.org,
	Keir Fraser <keir@xen.org>,
	stefano.stabellini@citrix.com, patches@linaro.org
Subject: Re: [PATCH for-4.5 7/8] xen/irq: Handle multiple action per IRQ
Date: Wed, 02 Apr 2014 15:01:40 +0100	[thread overview]
Message-ID: <533C1844.907@linaro.org> (raw)
In-Reply-To: <1396362699.8667.217.camel@kazak.uk.xensource.com>

On 04/01/2014 03:31 PM, Ian Campbell wrote:
> On Tue, 2014-04-01 at 14:52 +0100, Julien Grall wrote:
>> On 04/01/2014 02:23 PM, Ian Campbell wrote:
>>> On Tue, 2014-04-01 at 14:13 +0100, Julien Grall wrote:
>>>>>> 	- I need to use 2 variables to search for an element in a list as there is
>>>>>> 	no way to know after the end of the loop if we found or not an element.
>>>>>
>>>>> You've written that a bit weirdly IMHO.
>>>>>
>>>>> list_for_each(...)
>>>>>    if (not the one we want)
>>>>> 	continue
>>>>>    free the one we wanted
>>>>>    break;
>>>>>
>>>>> don't worry about warning on a non-existent IRQ, or set a simple
>>>>> boolean.
>>>>
>>>> We have to worry about non-existent action otherwise Xen may segfault...
>>>
>>> Why? If it doesn't exist we don't do anything.
>>>
>>>
>>
>> We can't free in the loop because the action may be used on another CPU
>> at the same it. (see "active" loop at the end). So I still need two
>> variables (one for the loop and one for the real action).
> 
> Perhaps the "goto found" pattern might help here then?

I'm not a big fan of "goto". But in this case the code might be cleaner.

-- 
Julien Grall