Re: [dpdk-dev] [PATCH] ethdev: missing typecast from void in eth_dev_pci_specific_init

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 4/12/2019 10:31 PM, Stephen Hemminger wrote:
> On Fri, 12 Apr 2019 18:29:46 +0100
> Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> 
>> On 4/12/2019 6:25 PM, Ferruh Yigit wrote:
>>> On 4/12/2019 6:15 PM, Ananyev, Konstantin wrote:  
>>>>
>>>>  
>>>>> -----Original Message-----
>>>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ferruh Yigit
>>>>> Sent: Friday, April 12, 2019 6:09 PM
>>>>> To: Stephen Hemminger <stephen@networkplumber.org>; Richardson, Bruce <bruce.richardson@intel.com>
>>>>> Cc: David Christensen <drc@linux.vnet.ibm.com>; thomas@monjalon.net; arybchenko@solarflare.com; dev@dpdk.org;
>>>>> radhika.chirra@ibm.com; stable@dpdk.org
>>>>> Subject: Re: [dpdk-dev] [PATCH] ethdev: missing typecast from void in eth_dev_pci_specific_init
>>>>>
>>>>> On 4/11/2019 12:08 AM, Stephen Hemminger wrote:  
>>>>>> On Wed, 10 Apr 2019 22:00:18 +0100
>>>>>> Bruce Richardson <bruce.richardson@intel.com> wrote:
>>>>>>  
>>>>>>> On Wed, Apr 10, 2019 at 03:16:16PM -0500, David Christensen wrote:  
>>>>>>>> The function eth_dev_pci_specific_init is missing a typecast to
>>>>>>>> (struct rte_pci_device *) for the input argument bus_device.
>>>>>>>>
>>>>>>>> Cc: stable@dpdk.org
>>>>>>>>
>>>>>>>> Signed-off-by: David Christensen <drc@linux.vnet.ibm.com>
>>>>>>>> Tested-by: Radhika Chirra <radhika.chirra@ibm.com>
>>>>>>>> ---
>>>>>>>>  lib/librte_ethdev/rte_ethdev_pci.h | 2 +-
>>>>>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>>>>
>>>>>>>> diff --git a/lib/librte_ethdev/rte_ethdev_pci.h b/lib/librte_ethdev/rte_ethdev_pci.h
>>>>>>>> index 23257e9..a325311 100644
>>>>>>>> --- a/lib/librte_ethdev/rte_ethdev_pci.h
>>>>>>>> +++ b/lib/librte_ethdev/rte_ethdev_pci.h
>>>>>>>> @@ -72,7 +72,7 @@
>>>>>>>>
>>>>>>>>  static inline int
>>>>>>>>  eth_dev_pci_specific_init(struct rte_eth_dev *eth_dev, void *bus_device) {
>>>>>>>> -	struct rte_pci_device *pci_dev = bus_device;
>>>>>>>> +	struct rte_pci_device *pci_dev = (struct rte_pci_device *)bus_device;
>>>>>>>>  
>>>>>>>
>>>>>>> Is this needed for building some C++ apps that are including the header
>>>>>>> file (directly, or indirectly), because for pure C, "void *" types should
>>>>>>> be assignable to any other pointer type without casting?
>>>>>>>
>>>>>>> /Bruce  
>>>>>>
>>>>>> Another example of Why the Hell is this inline?
>>>>>>  
>>>>>
>>>>> It has been done inline intentionally at the time as far as remember, this
>>>>> header is for drivers not for applications, it has helper functions.
>>>>>
>>>>> The common code from drivers related to the bus put into header files, so the
>>>>> code itself belongs to drivers not ethdev and reduces duplicates in them.  
>>>>
>>>> Ok that's the common code used by the drivers...
>>>> But why it still can't be in .c file?  
>>>
>>> When it is in .c file, it will be either in ethdev library, single location in
>>> .c file and binary file, but location is not exactly right, because code belongs
>>> to drivers.
>>> Or code should be in .c files of each drivers, this will be code duplication.
>>>
>>> Having in .h file makes code in single place, but when compiled code will be in
>>> each driver object file/ library.
>>>
>>> Of course it works when put into a .c file in ehtdev, but bus (pci and vdev)
>>> related code are not belongs to ethdev library and I believe shouldn't be part
>>> of ethdev binary. And those bus helper headers are only for drivers to include,
>>> so having inline shouldn't be a problem at all because there is not stability
>>> concern in that interface.
>>>   
>>
>> btw, if you put those into .c file in ethdev, you will be creating a dependency
>> from ethdev to bus code, to all available buses which will make impossible to
>> disable any bus type if you use ethdev.
> 
> The problem I see is rte_ethdev_pci.h, it should be headers only and then put
> code rte_ethdev_pci.c
> 

Where this 'rte_ethdev_pci.c' should be? Because of reasons explained above,
ehtdev is not good place.
Perhaps a 'common' folder for net drivers may work, create a 'rte_ethdev_pci.o'
and link it with relevant drivers.?