Re: [Qemu-devel] [PATCH] vfio/pci: replace 1 with PCI_CAP_LIST_NEXT to make code self-explain

[Wei Yang <richard.weiyang@gmail.com>]

On Wed, Mar 16, 2016 at 12:52:52PM +0100, Paolo Bonzini wrote:
>
>
>On 16/03/2016 12:27, Michael Tokarev wrote:
>>> >      for (tmp = pdev->config[PCI_CAPABILITY_LIST]; tmp;
>>> > -         tmp = pdev->config[tmp + 1]) {
>>> > +         tmp = pdev->config[tmp + PCI_CAP_LIST_NEXT]) {
>>> > -    next = pdev->config[pos + 1];
>>> > +    next = pdev->config[pos + PCI_CAP_LIST_NEXT];
>> Hmm. I'm not sure the new version is better, to me "+1" reads
>> easier than the new symbolic constant variant.
>> 
>> If it were something like pdev->config[PCI_CAP_LIST_NEXT], that'd be
>> nice, but not "pos + PCI_CAP_LIST_NEXT".
>> 
>> But again, I'm not pci config space expert and don't understand
>> the basics :)

Thanks Michael for your comment. By using the macro, audience is more easy to
understand it tries to get the position of next capability.

>
>Each capability is a node of a linked list, and the position of the next
>capability is at offset 1 inside the capability (here it is at offset 1
>from the tmp or pos base).  I think the patch is an improvement.
>

Thanks Paolo for your reply. :-) 

>Paolo

-- 
Wei Yang
Help you, Help me