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From: "Iremonger, Bernard" <bernard.iremonger@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
CC: "dev@dpdk.org" <dev@dpdk.org>, "thomas@monjalon.net" <thomas@monjalon.net>
Thread-Topic: [dpdk-dev] [PATCH v2 1/4] ethdev: modify callback process API
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Date: Wed, 21 Jun 2017 09:22:58 +0000
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Subject: Re: [dpdk-dev] [PATCH v2 1/4] ethdev: modify callback process API
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Hi Stephen,

> -----Original Message-----
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Thursday, June 15, 2017 4:43 PM
> To: Iremonger, Bernard <bernard.iremonger@intel.com>
> Cc: dev@dpdk.org; thomas@monjalon.net
> Subject: Re: [dpdk-dev] [PATCH v2 1/4] ethdev: modify callback process AP=
I
>=20
> On Mon, 12 Jun 2017 16:18:08 +0100
> Bernard Iremonger <bernard.iremonger@intel.com> wrote:
>=20
> > From: "Bernard.Iremonger" <Bernard.iremonger@intel.com>
> >
> > Change the rte_eth_dev_callback_process function to return int, and
> > add a void *ret_param parameter.
>=20
> What is the motivation for this? What is return value used for?

Since DPDK 16.11 the i40e and ixgbe PMD's have been returning data to the c=
alling process using the "void *cb_arg"  parameter of the callback_process =
API

void _rte_eth_dev_callback_process(struct rte_eth_dev *dev, enum rte_eth_ev=
ent_type event, void *cb_arg);

This was not considered to be ideal by Thomas who suggested adding a "void =
*ret_param"   parameter to API to return data to the calling process and at=
 the same time to change the return value from void to int to allow returni=
ng an error code if required. =20

Regards,

Bernard.