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Miller" , Linux Kernel Network Developers , "idosch@mellanox.com" , "saeedm@mellanox.com" Subject: Re: [PATCH v2 net-next 4/7] ipv6: Plumb support for nexthop object in a fib6_info Thread-Topic: [PATCH v2 net-next 4/7] ipv6: Plumb support for nexthop object in a fib6_info Thread-Index: AQHVGcH9d/t3D+2G4E2ABG2B/dN1r6aKO5OAgAAqigCAABVZAIAACmiAgAAIXYCAAAN5gP//prsAgAB/zgCAAEE1gA== Date: Tue, 4 Jun 2019 05:29:32 +0000 Message-ID: <20190604052929.4mlxa5sswm46mwrq@kafai-mbp.dhcp.thefacebook.com> References: <20190603040817.4825-1-dsahern@kernel.org> <20190603040817.4825-5-dsahern@kernel.org> <5263d3ae-1865-d935-cb03-f6dfd4604d15@gmail.com> <4cdcdf65-4d34-603e-cb21-d649b399d760@gmail.com> <20190604005840.tiful44xo34lpf6d@kafai-mbp.dhcp.thefacebook.com> <453565b0-d08a-be96-3cd7-5608d4c21541@gmail.com> In-Reply-To: <453565b0-d08a-be96-3cd7-5608d4c21541@gmail.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: MWHPR1001CA0014.namprd10.prod.outlook.com (2603:10b6:301:2a::27) To MWHPR15MB1790.namprd15.prod.outlook.com (2603:10b6:301:53::10) x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [2620:10d:c090:180::fce9] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 1c0e0246-98ad-4422-502f-08d6e8ad9f11 x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600148)(711020)(4605104)(1401327)(2017052603328)(7193020);SRVR:MWHPR15MB1376; x-ms-traffictypediagnostic: MWHPR15MB1376: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-forefront-prvs: 0058ABBBC7 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(346002)(366004)(396003)(39860400002)(136003)(376002)(189003)(199004)(64756008)(66446008)(6246003)(53936002)(66556008)(54906003)(478600001)(14454004)(86362001)(73956011)(66946007)(81166006)(8676002)(81156014)(4326008)(66476007)(8936002)(25786009)(229853002)(256004)(14444005)(6486002)(5660300002)(6916009)(476003)(11346002)(46003)(446003)(1076003)(486006)(186003)(71200400001)(71190400001)(6436002)(9686003)(6512007)(68736007)(1411001)(53546011)(316002)(7736002)(6506007)(386003)(102836004)(76176011)(305945005)(52116002)(99286004)(6116002)(2906002);DIR:OUT;SFP:1102;SCL:1;SRVR:MWHPR15MB1376;H:MWHPR15MB1790.namprd15.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; received-spf: None (protection.outlook.com: fb.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: fMU0HRZ4RnqpJUKOrIZxEE2zD2cdCbNC4Q1egz9ZTnNbf0Vb5/JoweGsIQ1+kR+y0swT9o7pNPiG+wF6qGEKw38+dVQyvO9jQj1UUFtGhy2PkOsVtehSjCK36N8oCVRoEYxsI25zd0Nb9gcDdkmMnwPEkGx63Li1qNjv8cOscJiJPZgEi7q/5QTuZtXyTFP+tuDtLqgSl87dpcEJ/JtDfrqi7A2L/+WQtJPhtTfkeF0o0mis0IwJzuin2cSsyKiMjKujKrVQCRgSnQs82JZO0Z8mHpcApvyCwCX/pSgrkCvAAPdyy7MNfULKVRFAJ8EV40m7+wYyLAX0rba9RRScVzQDgetMj5TIE8mrJmLu4SYgfooDwWBxSY7Qt6yuQ15EmsYG1D9QdzI6GTRB1chhTpZEbqRhgya+vHJB/BYCgmI= Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 1c0e0246-98ad-4422-502f-08d6e8ad9f11 X-MS-Exchange-CrossTenant-originalarrivaltime: 04 Jun 2019 05:29:32.8302 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: kafai@fb.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR15MB1376 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-04_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=972 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906040037 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Jun 03, 2019 at 07:36:06PM -0600, David Ahern wrote: > On 6/3/19 6:58 PM, Martin Lau wrote: > > I have concern on calling ip6_create_rt_rcu() in general which seems > > to trace back to this commit > > dec9b0e295f6 ("net/ipv6: Add rt6_info create function for ip6_pol_route= _lookup") > >=20 > > This rt is not tracked in pcpu_rt, rt6_uncached_list or exception bucke= t. > > In particular, how to react to NETDEV_UNREGISTER/DOWN like > > the rt6_uncached_list_flush_dev() does and calls dev_put()? > >=20 > > The existing callers seem to do dst_release() immediately without > > caching it, but still concerning. >=20 > those are the callers that don't care about the dst_entry, but are > forced to deal with it. Removing the tie between fib lookups an > dst_entry is again the right solution. Great to know that there will be a solution. It would be great if there is patch (or repo) to show how that may look like on those rt6_lookup() callers. Before that, although it seems fine now (__ip6_route_redirect() is harder to confirm since rt is passed around but it seems to be ok), instead of risking for "unregister_netdevice: waiting for eth0 to become fr= ee" in case some future patch is caching this rt, why pcpu_rt cannot be used in all occasions? and also avoid re-creating the same rt.