lkml.org 
[lkml]   [2012]   [Jul]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRE: [PATCH 01/90] staging: comedi: comedidev.h: introduce comedi_to_pci_dev() helper
On Thursday, July 19, 2012 9:32 AM, Dan Carpenter wrote:
> On Thu, Jul 19, 2012 at 11:20:52AM -0500, H Hartley Sweeten wrote:
>> On Thursday, July 19, 2012 2:23 AM, Ian Abbott wrote:
>>> That needs to be something like:
>>>
>>> return dev->hw_dev ? to_pci_dev(dev->hw_dev) : NULL;
>>
>> Hmm.. I'm not really sure.
>>
>> I assumed that the container_of() macro would return NULL if the ptr passed to
>> it was NULL. But, I'm not sure how this actually unwinds for that case.
>>
>> Greg, do you know if the NULL check is needed? It's is possible that the dev->hw_dev
>> pointer could be NULL.
>>
>
> container_of() just does pointer math with the offset. Since
> ->hw_dev is not the first member of the pci_dev struct then
> to_pci_dev() never returns NULL. If you give it a NULL pointer it
> returns a bogus pointer back.

Thanks for the information.

I'll update PATCH 01/90 and repost it as v2.

Thanks,
Hartley



\
 
 \ /
  Last update: 2012-07-19 20:01    [W:0.494 / U:0.176 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site