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Wed, 11 Jul 2018 22:48:01 -0700 (PDT) Date: Wed, 11 Jul 2018 22:48:01 -0700 (PDT) Message-Id: <20180711.224801.1129067473269289703.davem@davemloft.net> To: neilb@suse.com Cc: herbert@gondor.apana.org.au, tgraf@suug.ch, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, eric.dumazet@gmail.com Subject: Re: [PATCH resend] rhashtable: detect when object movement might have invalidated a lookup From: David Miller In-Reply-To: <20180711.224658.2077863065492745521.davem@davemloft.net> References: <20180601160613.7ud25g2ux55k3bma@gondor.apana.org.au> <87k1q8yh70.fsf@notabene.neil.brown.name> <20180711.224658.2077863065492745521.davem@davemloft.net> X-Mailer: Mew version 6.7 on Emacs 25.3 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=iso-8859-7 Content-Transfer-Encoding: base64 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 11 Jul 2018 22:48:01 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RnJvbTogRGF2aWQgTWlsbGVyIDxkYXZlbUBkYXZlbWxvZnQubmV0Pg0KRGF0ZTogV2VkLCAxMSBK dWwgMjAxOCAyMjo0Njo1OCAtMDcwMCAoUERUKQ0KDQo+IEZyb206IE5laWxCcm93biA8bmVpbGJA c3VzZS5jb20+DQo+IERhdGU6IEZyaSwgMDYgSnVsIDIwMTggMTc6MDg6MzUgKzEwMDANCj4gDQo+ PiANCj4+IFNvbWUgdXNlcnMgb2Ygcmhhc2h0YWJsZSBtaWdodCBuZWVkIHRvIGNoYW5nZSB0aGUg a2V5DQo+PiBvZiBhbiBvYmplY3QgYW5kIG1vdmUgaXQgdG8gYSBkaWZmZXJlbnQgbG9jYXRpb24g aW4gdGhlIHRhYmxlLg0KPj4gT3RoZXIgdXNlcnMgbWlnaHQgd2FudCB0byBhbGxvY2F0ZSBvYmpl Y3RzIHVzaW5nDQo+PiBTTEFCX1RZUEVTQUZFX0JZX1JDVSB3aGljaCBjYW4gcmVzdWx0IGluIHRo ZSBzYW1lIG1lbW9yeSBhbGxvY2F0aW9uDQo+PiBiZWluZyB1c2VkIGZvciBhIGRpZmZlcmVudCAo dHlwZS1jb21wYXRpYmxlKSBwdXJwb3NlIGFuZCBzaW1pbGFybHkNCj4+IGVuZCB1cCBpbiBhIGRp ZmZlcmVudCBoYXNoLWNoYWluLg0KPj4gDQo+PiBUbyBzdXBwb3J0IHRoZXNlLCB3ZSBzdG9yZSBh IHVuaXF1ZSBOVUxMU19NQVJLRVIgYXQgdGhlIGVuZCBvZg0KPj4gZWFjaCBjaGFpbiwgYW5kIHdo ZW4gYSBzZWFyY2ggZmFpbHMgdG8gZmluZCBhIG1hdGNoLCB3ZSBjaGVjaw0KPj4gaWYgdGhlIE5V TExTIG1hcmtlciBmb3VuZCB3YXMgdGhlIGV4cGVjdGVkIG9uZS4gIElmIG5vdCwNCj4+IHRoZSBz ZWFyY2ggaXMgcmVwZWF0ZWQuDQo+PiANCj4+IFRoZSB1bmlxdWUgTlVMTFNfTUFSS0VSIGlzIGRl cml2ZWQgZnJvbSB0aGUgYWRkcmVzcyBvZiB0aGUNCj4+IGhlYWQgb2YgdGhlIGNoYWluLg0KPj4g DQo+PiBJZiBhbiBvYmplY3QgaXMgcmVtb3ZlZCBhbmQgcmUtYWRkZWQgdG8gdGhlIHNhbWUgaGFz aCBjaGFpbiwgd2Ugd29uJ3QNCj4+IG5vdGljZSBieSBsb29raW5nIHRoYXQgdGhlIE5VTExTIG1h cmtlci4gIEluIHRoaXMgY2FzZSB3ZSBtdXN0IGJlIHN1cmUNCj4+IHRoYXQgaXQgd2FzIG5vdCBy ZS1hZGRlZCAqYWZ0ZXIqIGl0cyBvcmlnaW5hbCBsb2NhdGlvbiwgb3IgYSBsb29rdXAgbWF5DQo+ PiBpbmNvcnJlY3RseSBmYWlsLiAgVGhlIGVhc2llc3Qgc29sdXRpb24gaXMgdG8gZW5zdXJlIGl0 IGlzIGluc2VydGVkIGF0DQo+PiB0aGUgc3RhcnQgb2YgdGhlIGNoYWluLiAgaW5zZXJ0X3Nsb3co KSBhbHJlYWR5IGRvZXMgdGhhdCwNCj4+IGluc2VydF9mYXN0KCkgZG9lcyBub3QuICBTbyB0aGlz IHBhdGNoIGNoYW5nZXMgaW5zZXJ0X2Zhc3QgdG8gYWx3YXlzDQo+PiBpbnNlcnQgYXQgdGhlIGhl YWQgb2YgdGhlIGNoYWluLg0KPj4gDQo+PiBOb3RlIHRoYXQgc3VjaCBhIHVzZXIgbXVzdCBkbyB0 aGVpciBvd24gZG91YmxlLWNoZWNraW5nIG9mDQo+PiB0aGUgb2JqZWN0IGZvdW5kIGJ5IHJoYXNo dGFibGVfbG9va3VwX2Zhc3QoKSBhZnRlciBlbnN1cmluZw0KPj4gbXV0dWFsIGV4Y2x1c2lvbiB3 aGljaCBhbnl0aGluZyB0aGF0IG1pZ2h0IGNoYW5nZSB0aGUga2V5LCBzdWNoIGFzDQo+PiBzdWNj ZXNzZnVsbHkgdGFraW5nIGEgbmV3IHJlZmVyZW5jZS4NCj4+IA0KPj4gU2lnbmVkLW9mZi1ieTog TmVpbEJyb3duIDxuZWlsYkBzdXNlLmNvbT4NCj4gDQo+IEFwcGxpZWQgdG8gbmV0LW5leHQuDQoN CkFjdHVhbGx5LCByZXZlcnRlZCwgaXQgZG9lc24ndCBldmVuIGNvbXBpbGUuDQoNCmxpYi9yaGFz aHRhYmxlLmM6IEluIGZ1bmN0aW9uIKFyaHRfYnVja2V0X25lc3RlZKI6DQpsaWIvcmhhc2h0YWJs ZS5jOjExODc6Mzk6IGVycm9yOiBtYWNybyAiSU5JVF9SSFRfTlVMTFNfSEVBRCIgcGFzc2VkIDMg YXJndW1lbnRzLCBidXQgdGFrZXMganVzdCAxDQogICAgSU5JVF9SSFRfTlVMTFNfSEVBRChyaG51 bGwsIE5VTEwsIDApOw0KICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgICAgXg0K bGliL3JoYXNodGFibGUuYzoxMTg3OjQ6IGVycm9yOiChSU5JVF9SSFRfTlVMTFNfSEVBRKIgdW5k ZWNsYXJlZCAoZmlyc3QgdXNlIGluIHRoaXMgZnVuY3Rpb24pOyBkaWQgeW91IG1lYW4goUlOSVRf TElTVF9IRUFEoj8NCiAgICBJTklUX1JIVF9OVUxMU19IRUFEKHJobnVsbCwgTlVMTCwgMCk7DQog ICAgXn5+fn5+fn5+fn5+fn5+fn5+fg0KICAgIElOSVRfTElTVF9IRUFEDQpsaWIvcmhhc2h0YWJs ZS5jOjExODc6NDogbm90ZTogZWFjaCB1bmRlY2xhcmVkIGlkZW50aWZpZXIgaXMgcmVwb3J0ZWQg b25seSBvbmNlIGZvciBlYWNoIGZ1bmN0aW9uIGl0IGFwcGVhcnMgaW4NCg==