On Wed, Dec 14, 2016 at 6:12 AM, Shreyansh Jain <shreyansh.j...@nxp.com> wrote:
> On Wednesday 14 December 2016 03:54 AM, Jan Blunck wrote:
>>
>> On Tue, Dec 13, 2016 at 2:37 PM, Shreyansh Jain <shreyansh.j...@nxp.com>
>> wrote:
>>>
>>> From: Jan Blunck <jblu...@infradead.org>
>>>
>>> This macro is based on Jan Viktorin's original patch but also checks the
>>> type of the passed pointer against the type of the member.
>>>
>>> Signed-off-by: Jan Viktorin <vikto...@rehivetech.com>
>>> [shreyansh.j...@nxp.com: Fix checkpatch error]
>>> Signed-off-by: Shreyansh Jain <shreyansh.j...@nxp.com>
>>> [jblu...@infradead.org: add type checking and __extension__]
>>> Signed-off-by: Jan Blunck <jblu...@infradead.org>
>>>
>>> --
>>> v2:
>>> - fix checkpatch error
>>> ---
>>> lib/librte_eal/common/include/rte_common.h | 21 +++++++++++++++++++++
>>> 1 file changed, 21 insertions(+)
>>>
>>> diff --git a/lib/librte_eal/common/include/rte_common.h
>>> b/lib/librte_eal/common/include/rte_common.h
>>> index db5ac91..3eb8d11 100644
>>> --- a/lib/librte_eal/common/include/rte_common.h
>>> +++ b/lib/librte_eal/common/include/rte_common.h
>>> @@ -331,6 +331,27 @@ rte_bsf32(uint32_t v)
>>> #define offsetof(TYPE, MEMBER) __builtin_offsetof (TYPE, MEMBER)
>>> #endif
>>>
>>> +/**
>>> + * Return pointer to the wrapping struct instance.
>>> + *
>>> + * Example:
>>> + *
>>> + * struct wrapper {
>>> + * ...
>>> + * struct child c;
>>> + * ...
>>> + * };
>>> + *
>>> + * struct child *x = obtain(...);
>>> + * struct wrapper *w = container_of(x, struct wrapper, c);
>>> + */
>>> +#ifndef container_of
>>> +#define container_of(ptr, type, member) (__extension__ ({
>>> \
>>> + typeof(((type *)0)->member) * _ptr = (ptr); \
>>> + (type *)(((char *)_ptr) - offsetof(type,
>>> member));\
>>> + }))
>>
>>
>> This is a checkpatch false positive. It should be fine to ignore this.
>> IIRC we already discussed this before.
>
>
> I too thought something similar was discussed. I tried searching the
> archives but couldn't find anything - thus, I thought probably I was
> hallucinating :P
>
> So, you want me to revert back the '()' change? Does it impact the expansion
> of this macro?
We haven't added this on any other usage of the __extension__ keyword
in the existing code. From my perspective it is more consistent to
revert it.
Anyone else with an opinion here? David? Thomas?
>
>>
>>
>>> +#endif
>>> +
>>> #define _RTE_STR(x) #x
>>> /** Take a macro value and get a string version of it */
>>> #define RTE_STR(x) _RTE_STR(x)
>>> --
>>> 2.7.4
>>>
>>
>
