Re: [dpdk-dev] [RFC 19.11 v2 1/3] ethdev: hide key ethdev structures from public API

[Jerin Jacob <jerinjacobk@gmail.com>]

On Mon, Sep 9, 2019 at 3:54 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>
> On 9/9/2019 11:02 AM, Zapolski, MarcinX A wrote:
> >> -----Original Message-----
> >> From: Yigit, Ferruh
> >> Sent: Monday, September 9, 2019 12:00 PM
> >> To: Zapolski, MarcinX A <marcinx.a.zapolski@intel.com>; dev@dpdk.org
> >> Subject: Re: [dpdk-dev] [RFC 19.11 v2 1/3] ethdev: hide key ethdev
> >> structures from public API
> >>
> >> On 9/9/2019 9:07 AM, Zapolski, MarcinX A wrote:
> >>>> -----Original Message-----
> >>>> From: Yigit, Ferruh
> >>>> Sent: Friday, September 6, 2019 4:38 PM
> >>>> To: Zapolski, MarcinX A <marcinx.a.zapolski@intel.com>; dev@dpdk.org
> >>>> Subject: Re: [dpdk-dev] [RFC 19.11 v2 1/3] ethdev: hide key ethdev
> >>>> structures from public API
> >>>>
> >>>> On 9/6/2019 2:18 PM, Marcin Zapolski wrote:
> >>>>> Split rte_eth_dev structure to two parts: head that is available for
> >>>>> user applications, and rest which is DPDK internal.
> >>>>> Make an array of pointers to rte_eth_dev structures available for
> >>>>> user applications.
> >>>>>
> >>>>> Signed-off-by: Marcin Zapolski <marcinx.a.zapolski@intel.com>
> >>>>
> >>>> <...>
> >>>>
> >>>>> diff --git a/lib/librte_bitratestats/rte_bitrate.c
> >>>>> b/lib/librte_bitratestats/rte_bitrate.c
> >>>>> index 639e47547..82d469514 100644
> >>>>> --- a/lib/librte_bitratestats/rte_bitrate.c
> >>>>> +++ b/lib/librte_bitratestats/rte_bitrate.c
> >>>>> @@ -3,7 +3,7 @@
> >>>>>   */
> >>>>>
> >>>>>  #include <rte_common.h>
> >>>>> -#include <rte_ethdev.h>
> >>>>> +#include <rte_ethdev_driver.h>
> >>>>
> >>>> This is in the library, not sure if libraries should include the
> >>>> header file for the drivers, can you please explain why this change is
> >> needed?
> >>>>
> >>> It is needed to make rte_eth_dev structure available. But yes, I agree that
> >> it will be more appropriate to include rte_ethdev.h and rte_ethdev_core.h
> >> separately. I probably wanted less includes, silly me.
> >>>> <...>
> >>>>
> >>>>> @@ -6,6 +6,7 @@
> >>>>>  #define _RTE_ETHDEV_PROFILE_H_
> >>>>>
> >>>>>  #include "rte_ethdev.h"
> >>>>> +#include "rte_ethdev_core.h"
> >>>>>
> >>>>>  /**
> >>>>>   * Initialization of the Ethernet device profiling.
> >>>>> diff --git a/lib/librte_ethdev/rte_ethdev.c
> >>>>> b/lib/librte_ethdev/rte_ethdev.c index 17d183e1f..5c6cc640a 100644
> >>>>> --- a/lib/librte_ethdev/rte_ethdev.c
> >>>>> +++ b/lib/librte_ethdev/rte_ethdev.c
> >>>>> @@ -40,6 +40,7 @@
> >>>>>
> >>>>>  #include "rte_ether.h"
> >>>>>  #include "rte_ethdev.h"
> >>>>> +#include "rte_ethdev_core.h"
> >>>>>  #include "rte_ethdev_driver.h"
> >>>>>  #include "ethdev_profile.h"
> >>>>>  #include "ethdev_private.h"
> >>>>
> >>>> I was hoping "rte_ethdev_core.h" can be removed completely by
> >>>> distributing its content to "ethdev_private.h", "rte_ethdev_driver.h"
> >>>> and perhaps even to "rte_ethdev.h".
> >>>>
> >>>> Can you please explain what prevents removing "rte_ethdev_core.h"?
> >>> I could rename it to rte_ethdev_private. There is just rte_eth_dev and
> >> rte_eth_dev_data left in it.
> >>>
> >>
> >> I think drivers access to both 'rte_eth_dev' and 'rte_eth_dev_data' so can't
> >> move them to 'ethdev_private.h' why not move it to 'rte_ethdev_driver.h'?
> >
> > Because the libraries use them as well.
> >
>
> These are 'librte_ethdev' library internal data, I think other libraries
> shouldn't access them directly.
>
> As far as I can see,
> librte_eventdev  => rte_eth_dev_data
> librte_eventdev  => rte_eth_dev
> librte_telemetry => rte_eth_dev
>
> Can you see any other library accessing 'rte_eth_dev' and 'rte_eth_dev_data' ?
>
>
> I am not sure about 'eventdev', specially because of the Rx/Tx adapters of it,
> perhaps they can include the "rte_ethdev_driver.h", cc'ed Jerin.

Yes.

Overall this patch theme looks good to me. I will wait for v3 to
change PMDs I maintains.

My only comment is, We should make rte_ethdev_driver.h as private
i.e it should not be included by applications.

Currently. On dpdk install, the private header file is copied to prefix

ie

make install T=x86_64-native-linux-gcc DESTDIR=install

[master][dpdk.org] $ ls install/include/dpdk/rte_ethdev_driver.h
install/include/dpdk/rte_ethdev_driver.h

The internal libraries can access the header file through the
following scheme without exposing it as public.

CFLAGS += -I$(RTE_SDK)/lib/librte_ethdev/

in .c file

#include "ethdev_driver.h"