From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "tj@kernel.org" CC: "hch@lst.de" , "linux-block@vger.kernel.org" , "axboe@kernel.dk" Subject: Re: [PATCH v2] blk-mq: Fix race between resetting the timer and completion handling Date: Wed, 7 Feb 2018 17:27:10 +0000 Message-ID: <1518024428.2870.35.camel@wdc.com> References: <20180207011133.25957-1-bart.vanassche@wdc.com> <20180207170612.GB695913@devbig577.frc2.facebook.com> In-Reply-To: <20180207170612.GB695913@devbig577.frc2.facebook.com> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 List-ID: T24gV2VkLCAyMDE4LTAyLTA3IGF0IDA5OjA2IC0wODAwLCBUZWp1biBIZW8gd3JvdGU6DQo+IE9u IFR1ZSwgRmViIDA2LCAyMDE4IGF0IDA1OjExOjMzUE0gLTA4MDAsIEJhcnQgVmFuIEFzc2NoZSB3 cm90ZToNCj4gPiBUaGUgZm9sbG93aW5nIHJhY2UgY2FuIG9jY3VyIGJldHdlZW4gdGhlIGNvZGUg dGhhdCByZXNldHMgdGhlIHRpbWVyDQo+ID4gYW5kIGNvbXBsZXRpb24gaGFuZGxpbmc6DQo+ID4g LSBUaGUgY29kZSB0aGF0IGhhbmRsZXMgQkxLX0VIX1JFU0VUX1RJTUVSIHJlc2V0cyBhYm9ydGVk X2dzdGF0ZS4NCj4gPiAtIEEgY29tcGxldGlvbiBvY2N1cnMgYW5kIGJsa19tcV9jb21wbGV0ZV9y ZXF1ZXN0KCkgY2FsbHMNCj4gPiAgIF9fYmxrX21xX2NvbXBsZXRlX3JlcXVlc3QoKS4NCj4gPiAt IFRoZSB0aW1lb3V0IGNvZGUgY2FsbHMgYmxrX2FkZF90aW1lcigpIGFuZCB0aGF0IGZ1bmN0aW9u IHNldHMgdGhlDQo+ID4gICByZXF1ZXN0IGRlYWRsaW5lIGFuZCBhZGp1c3RzIHRoZSB0aW1lci4N Cj4gPiAtIF9fYmxrX21xX2NvbXBsZXRlX3JlcXVlc3QoKSBmcmVlcyB0aGUgcmVxdWVzdCB0YWcu DQo+ID4gLSBUaGUgdGltZXIgZmlyZXMgYW5kIHRoZSB0aW1lb3V0IGhhbmRsZXIgZ2V0cyBjYWxs ZWQgZm9yIGEgZnJlZWQNCj4gPiAgIHJlcXVlc3QuDQo+IA0KPiBDYW4geW91IHNlZSB3aGV0aGVy IGJ5IGFueSBjaGFuY2UgdGhlIGZvbGxvd2luZyBwYXRjaCBmaXhlcyB0aGUgaXNzdWU/DQo+IElm IG5vdCwgY2FuIHlvdSBzaGFyZSB0aGUgcmVwcm8gY2FzZT8NCj4gDQo+IFRoYW5rcy4NCj4gDQo+ IGRpZmYgLS1naXQgYS9ibG9jay9ibGstbXEuYyBiL2Jsb2NrL2Jsay1tcS5jDQo+IGluZGV4IGRm OTMxMDIuLjY1MWQxOGMgMTAwNjQ0DQo+IC0tLSBhL2Jsb2NrL2Jsay1tcS5jDQo+ICsrKyBiL2Js b2NrL2Jsay1tcS5jDQo+IEBAIC04MzYsOCArODM2LDggQEAgc3RhdGljIHZvaWQgYmxrX21xX3Jx X3RpbWVkX291dChzdHJ1Y3QgcmVxdWVzdCAqcmVxLCBib29sIHJlc2VydmVkKQ0KPiAgCQkgKiAt PmFib3J0ZWRfZ3N0YXRlIGlzIHNldCwgdGhpcyBtYXkgbGVhZCB0byBpZ25vcmVkDQo+ICAJCSAq IGNvbXBsZXRpb25zIGFuZCBmdXJ0aGVyIHNwdXJpb3VzIHRpbWVvdXRzLg0KPiAgCQkgKi8NCj4g LQkJYmxrX21xX3JxX3VwZGF0ZV9hYm9ydGVkX2dzdGF0ZShyZXEsIDApOw0KPiAgCQlibGtfYWRk X3RpbWVyKHJlcSk7DQo+ICsJCWJsa19tcV9ycV91cGRhdGVfYWJvcnRlZF9nc3RhdGUocmVxLCAw KTsNCj4gIAkJYnJlYWs7DQo+ICAJY2FzZSBCTEtfRUhfTk9UX0hBTkRMRUQ6DQo+ICAJCWJyZWFr Ow0KDQpIZWxsbyBUZWp1biwNCg0KRXZlbiB3aXRoIHRoZSBhYm92ZSBjaGFuZ2UgSSB0aGluayB0 aGF0IHRoZXJlIGlzIHN0aWxsIGEgcmFjZSBiZXR3ZWVuIHRoZQ0KY29kZSB0aGF0IGhhbmRsZXMg dGltZXIgcmVzZXRzIGFuZCB0aGUgY29tcGxldGlvbiBoYW5kbGVyLiBBbnl3YXksIHRoZSB0ZXN0 DQp3aXRoIHdoaWNoIEkgdHJpZ2dlcmVkIHRoZXNlIHJhY2VzIGlzIGFzIGZvbGxvd3M6DQotIFN0 YXJ0IGZyb20gd2hhdCB3aWxsIGJlY29tZSBrZXJuZWwgdjQuMTYtcmMxIGFuZCBhcHBseSB0aGUg cGF0Y2ggdGhhdCBhZGRzDQogIFNSUCBvdmVyIFJvQ0Ugc3VwcG9ydCB0byB0aGUgaWJfc3JwdCBk cml2ZXIuIFNlZSBhbHNvIHRoZSAiW1BBVENIIHYyIDAwLzE0XQ0KICBJQi9zcnB0OiBBZGQgUkRN QS9DTSBzdXBwb3J0IiBwYXRjaCBzZXJpZXMNCiAgKGh0dHBzOi8vd3d3LnNwaW5pY3MubmV0L2xp c3RzL2xpbnV4LXJkbWEvbXNnNTk1ODkuaHRtbCkuDQotIEFwcGx5IG15IHBhdGNoIHNlcmllcyB0 aGF0IGZpeGVzIGEgcmFjZSBiZXR3ZWVuIHRoZSBTQ1NJIGVycm9yIGhhbmRsZXIgYW5kDQogIFND U0kgdHJhbnNwb3J0IHJlY292ZXJ5Lg0KLSBBcHBseSBteSBwYXRjaCBzZXJpZXMgdGhhdCBpbXBy b3ZlcyB0aGUgc3RhYmlsaXR5IG9mIHRoZSBTQ1NJIHRhcmdldCBjb3JlDQogIChMSU8pLg0KLSBC dWlsZCBhbmQgaW5zdGFsbCB0aGF0IGtlcm5lbC4NCi0gQ2xvbmUgdGhlIGZvbGxvd2luZyByZXBv c2l0b3J5OiBodHRwczovL2dpdGh1Yi5jb20vYnZhbmFzc2NoZS9zcnAtdGVzdC4NCi0gUnVuIHRo ZSBmb2xsb3dpbmcgdGVzdDoNCiAgd2hpbGUgdHJ1ZTsgZG8gc3JwLXRlc3QvcnVuX3Rlc3RzIC1j IC10IDAyLW1xOyBkb25lDQotIFdoaWxlIHRoZSB0ZXN0IGlzIHJ1bm5pbmcsIGNoZWNrIHdoZXRo ZXIgb3Igbm90IHNvbWV0aGluZyB3ZWlyZCBoYXBwZW5zLg0KICBTb21ldGltZXMgSSBzZWUgdGhh dCBzY3NpX3RpbWVzX291dCgpIGNyYXNoZXMuIFNvbWV0aW1lcyBJIHNlZSB3aGlsZSBydW5uaW5n DQogIHRoaXMgdGVzdCB0aGF0IGEgc29mdCBsb2NrdXAgaXMgcmVwb3J0ZWQgaW5zaWRlIGJsa19t cV9kb19kaXNwYXRjaF9jdHgoKS4NCg0KSWYgeW91IHdhbnQgSSBjYW4gc2hhcmUgdGhlIHRyZWUg b24gZ2l0aHViIHRoYXQgSSB1c2UgbXlzZWxmIGZvciBteSB0ZXN0cy4NCg0KVGhhbmtzLA0KDQpC YXJ0Lg==