Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Oleksandr Mazur <oleksandr.mazur@plvision.eu>
To:     Ido Schimmel <idosch@idosch.org>
CC:     "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "jiri@nvidia.com" <jiri@nvidia.com>,
        "davem@davemloft.net" <davem@davemloft.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "kuba@kernel.org" <kuba@kernel.org>
Subject: Re: [PATCH net-next] net: core: devlink: add new trap action
 HARD_DROP
Thread-Topic: [PATCH net-next] net: core: devlink: add new trap action
 HARD_DROP
Thread-Index: AQHW7+i5SANyTFamkUKbFKKw5ahdBKoyAC0AgAFQP3o=
Date:   Fri, 22 Jan 2021 08:30:13 +0000
Message-ID: <AM0P190MB0738E480C28682A1744562EBE4A00@AM0P190MB0738.EURP190.PROD.OUTLOOK.COM>
References: <20210121112937.30989-1-oleksandr.mazur@plvision.eu>,<20210121122152.GA2647590@shredder.lan>
In-Reply-To: <20210121122152.GA2647590@shredder.lan>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="Windows-1252"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 225e31f9-962c-4c66-8177-08d8beaff097
X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Jan 2021 08:30:13.7492
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 03707b74-30f3-46b6-a0e0-ff0a7438c9c4
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: xsSigI7vBWfrSdw89A6cUVBqVcflMfqLdUovCG/oVide+1Pp6LP0Ak4ezUJ6dtFz+To1vhCeGMU8VLucGSsrXDoXMbVqJ2nijFX52Y7aupQ=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM9P190MB1282
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Ido Schimmel <idosch@idosch.org>=0A=
Sent: Thursday, January 21, 2021 2:21 PM=0A=
To: Oleksandr Mazur <oleksandr.mazur@plvision.eu>=0A=
Cc: netdev@vger.kernel.org <netdev@vger.kernel.org>; jiri@nvidia.com <jiri@=
nvidia.com>; davem@davemloft.net <davem@davemloft.net>; linux-kernel@vger.k=
ernel.org <linux-kernel@vger.kernel.org>; kuba@kernel.org <kuba@kernel.org>=
=0A=
Subject: Re: [PATCH net-next] net: core: devlink: add new trap action HARD_=
DROP =0A=
=A0=0A=
On Thu, Jan 21, 2021 at 01:29:37PM +0200, Oleksandr Mazur wrote:=0A=
>> Add new trap action HARD_DROP, which can be used by the=0A=
>> drivers to register traps, where it's impossible to get=0A=
>> packet reported to the devlink subsystem by the device=0A=
>> driver, because it's impossible to retrieve dropped packet=0A=
>> from the device itself.=0A=
>> In order to use this action, driver must also register=0A=
>> additional devlink operation - callback that is used=0A=
>> to retrieve number of packets that have been dropped by=0A=
>> the device.=0A=
=0A=
>Are these global statistics about number of packets the hardware dropped=
=0A=
> for a specific reason or are these per-port statistics?=0A=
=0A=
Global statistics. Basically, it=92s the DROP action, with the only differe=
nce that device might be unable to post the packet to the devlink subsystem=
.=0A=
Also, as this is an action, it could also be altered: e.g. changed to =91mi=
rror=92 or else.=0A=
=0A=
> Anyway, this patch really needs to be marked as "RFC" since we cannot=0A=
> add infrastructure without anyone using it.=0A=
=0A=
Will do.=0A=
Also, should I make a V2 patch, that will already hold the RFC tag and the =
changes (which include the commentaries fixes)?=0A=
=0A=
> Additionally, the documentation=0A=
> (Documentation/networking/devlink/devlink-trap.rst) needs to be updated,=
=0A=
> netdevsim needs to be patched and the test over netdevsim=0A=
> (tools/testing/selftests/drivers/net/netdevsim/devlink_trap.sh) needs to=
=0A=
> be extended to cover the new functionality.=0A=
=0A=
Okay. Will do.=0A=
=0A=
>> @@ -9876,6 +9915,9 @@ void devlink_trap_report(struct devlink *devlink, =
struct sk_buff *skb,=0A=
>>  {=0A=
>>        struct devlink_trap_item *trap_item =3D trap_ctx;=0A=
>> =0A=
>> +     if (trap_item->action =3D=3D DEVLINK_TRAP_ACTION_HARD_DROP)=0A=
>> +             return;=0A=
=0A=
>How can this happen?=0A=
=0A=
My bad. Will get removed in V2.=