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 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.