From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "joseph.qi@linux.alibaba.com" , "axboe@kernel.dk" CC: "hch@lst.de" , "ulf.hansson@linaro.org" , "linux-block@vger.kernel.org" , "philipp.reisner@linbit.com" , "stable@vger.kernel.org" , "keescook@chromium.org" Subject: Re: [PATCH v2 2/2] block: Fix a race between the throttling code and request queue initialization Date: Thu, 1 Feb 2018 16:16:02 +0000 Message-ID: <1517501761.2746.21.camel@wdc.com> References: <20180131235300.12773-1-bart.vanassche@wdc.com> <20180131235300.12773-3-bart.vanassche@wdc.com> <1ff1b2fa-ffe1-20f4-6be9-919c6a5b8227@linux.alibaba.com> In-Reply-To: <1ff1b2fa-ffe1-20f4-6be9-919c6a5b8227@linux.alibaba.com> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 List-ID: T24gVGh1LCAyMDE4LTAyLTAxIGF0IDA5OjUzICswODAwLCBKb3NlcGggUWkgd3JvdGU6DQo+IEkn bSBhZnJhaWQgdGhlIHJpc2sgbWF5IGFsc28gZXhpc3QgaW4gYmxrX2NsZWFudXBfcXVldWUsIHdo aWNoIHdpbGwNCj4gc2V0IHF1ZXVlX2xvY2sgdG8gdG8gdGhlIGRlZmF1bHQgaW50ZXJuYWwgbG9j ay4NCj4gDQo+IHNwaW5fbG9ja19pcnEobG9jayk7DQo+IGlmIChxLT5xdWV1ZV9sb2NrICE9ICZx LT5fX3F1ZXVlX2xvY2spDQo+IAlxLT5xdWV1ZV9sb2NrID0gJnEtPl9fcXVldWVfbG9jazsNCj4g c3Bpbl91bmxvY2tfaXJxKGxvY2spOw0KPiANCj4gSSdtIHRoaW5raW5nIG9mIGdldHRpbmcgYmxr Zy0+cS0+cXVldWVfbG9jayB0byBsb2NhbCBmaXJzdCwgYnV0IHRoaXMNCj4gd2lsbCByZXN1bHQg aW4gc3RpbGwgdXNpbmcgZHJpdmVyIGxvY2sgZXZlbiB0aGUgcXVldWVfbG9jayBoYXMgYWxyZWFk eQ0KPiBiZWVuIHNldCB0byB0aGUgZGVmYXVsdCBpbnRlcm5hbCBsb2NrLg0KDQpIZWxsbyBKb3Nl cGgsDQoNCkkgdGhpbmsgdGhlIHJhY2UgYmV0d2VlbiB0aGUgcXVldWVfbG9jayBhc3NpZ25tZW50 IGluIGJsa19jbGVhbnVwX3F1ZXVlKCkNCmFuZCB0aGUgdXNlIG9mIHRoYXQgcG9pbnRlciBieSBj Z3JvdXAgYXR0cmlidXRlcyBjb3VsZCBiZSBzb2x2ZWQgYnkNCnJlbW92aW5nIHRoZSB2aXNpYmls aXR5IG9mIHRoZXNlIGF0dHJpYnV0ZXMgZnJvbSBibGtfY2xlYW51cF9xdWV1ZSgpIGluc3RlYWQN Cm9mIF9fYmxrX3JlbGVhc2VfcXVldWUoKS4gSG93ZXZlciwgbGFzdCB0aW1lIEkgcHJvcG9zZWQg dG8gbW92ZSBjb2RlIGZyb20NCl9fYmxrX3JlbGVhc2VfcXVldWUoKSBpbnRvIGJsa19jbGVhbnVw X3F1ZXVlKCkgSSByZWNlaXZlZCB0aGUgZmVlZGJhY2sgdGhhdA0KZnJvbSBzb21lIGtlcm5lbCBk ZXZlbG9wZXJzIHRoYXQgdGhleSBkaWRuJ3QgbGlrZSB0aGlzLg0KDQpJcyB0aGUgYmxvY2sgZHJp dmVyIHRoYXQgdHJpZ2dlcmVkIHRoZSByYWNlIG9uIHRoZSBxLT5xdWV1ZV9sb2NrIGFzc2lnbm1l bnQNCnVzaW5nIGxlZ2FjeSAoc2luZ2xlIHF1ZXVlKSBvciBtdWx0aXF1ZXVlIChibGstbXEpIG1v ZGU/IElmIHRoYXQgZHJpdmVyIGlzDQp1c2luZyBsZWdhY3kgbW9kZSwgYXJlIHlvdSBhd2FyZSB0 aGF0IHRoZXJlIGFyZSBwbGFucyB0byByZW1vdmUgbGVnYWN5IG1vZGUNCmZyb20gdGhlIHVwc3Ry ZWFtIGtlcm5lbD8gQW5kIGlmIHlvdXIgZHJpdmVyIGlzIHVzaW5nIG11bHRpcXVldWUgbW9kZSwg aG93DQphYm91dCB0aGUgZm9sbG93aW5nIGNoYW5nZSBpbnN0ZWFkIG9mIHRoZSB0d28gcGF0Y2hl cyBpbiB0aGlzIHBhdGNoIHNlcmllczoNCg0KLS0tIGEvYmxvY2svYmxrLWNvcmUuYw0KKysrIGIv YmxvY2svYmxrLWNvcmUuYw0KQEAgLTEwOTMsNyArMTA5Myw3IEBAIGJsa19pbml0X3F1ZXVlX25v ZGUocmVxdWVzdF9mbl9wcm9jICpyZm4sIHNwaW5sb2NrX3QgKmxvY2ssIGludCBub2RlX2lkKQ0K IAkJcmV0dXJuIE5VTEw7DQogDQogCXEtPnJlcXVlc3RfZm4gPSByZm47DQotCWlmIChsb2NrKQ0K KwlpZiAoIXEtPm1xX29wcyAmJiBsb2NrKQ0KIAkJcS0+cXVldWVfbG9jayA9IGxvY2s7DQogCWlm IChibGtfaW5pdF9hbGxvY2F0ZWRfcXVldWUocSkgPCAwKSB7DQogCQlibGtfY2xlYW51cF9xdWV1 ZShxKTsNCg0KVGhhbmtzLA0KDQpCYXJ0Lg==