From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "jianchao.w.wang@oracle.com" , "axboe@kernel.dk" CC: "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" Subject: Re: [PATCH] blk-mq: use mutex_trylock to avoid lock inversion Date: Wed, 20 Jun 2018 16:18:49 +0000 Message-ID: <2c2003ff1baac05688495677f67239d52f6d9527.camel@wdc.com> References: <1529391637-1704-1-git-send-email-jianchao.w.wang@oracle.com> <2409013d789ca266879d24c815b76c2193e23fe3.camel@wdc.com> In-Reply-To: Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 List-ID: T24gV2VkLCAyMDE4LTA2LTIwIGF0IDEwOjA5ICswODAwLCBqaWFuY2hhby53YW5nIHdyb3RlOg0K PiBJdCBpcyB2ZXJ5IGVhc3kgdG8gcmVwcm9kdWNlIHdpdGggZm9sbG93aW5nIHNjcmlwdHMuDQo+ IA0KPiBzY3JpcHQgMA0KPiB3aGlsZSB0cnVlDQo+IGRvDQo+IAltb2Rwcm9iZSBudWxsX2JsayBx dWV1ZV9tb2RlPTIgc2hhcmVkX3RhZ3M9MQ0KPiAJc2xlZXAgMC4xDQo+IAlybW1vZCBudWxsX2Js aw0KPiAJc2xlZXAgMC4xDQo+IGRvbmUNCj4gDQo+IHNjcmlwdCAxDQo+IGZpbGUwPSIvc3lzL2Js b2NrL251bGxiMC9tcS8wL25yX3RhZ3MiDQo+IGZpbGUxPSIvc3lzL2Jsb2NrL251bGxiMC9tcS8w L2NwdTAvcnFfbGlzdCINCj4gd2hpbGUgdHJ1ZTsNCj4gZG8NCj4gCWlmIFsgLWUgJGZpbGUwIF07 dGhlbg0KPiAJCWNhdCAkZmlsZTANCj4gCWZpDQo+IAlpZiBbIC1lICRmaWxlMSBdO3RoZW4NCj4g CQljYXQgJGZpbGUxDQo+IAlmaQ0KPiBkb25lDQoNCkhlbGxvIEppYW5jaGFvLA0KDQpUaGFua3Mg Zm9yIGhhdmluZyBzaGFyZWQgYSByZXByb2R1Y2VyLiBIb3dldmVyLCB0aGUgYXBwcm9hY2ggb2Yg dGhlIHBhdGNoIHlvdQ0KcG9zdGVkIGRvZXNuJ3Qgc2VlbSBsaWtlIHRoZSByaWdodCBhcHByb2Fj aCB0byBtZS4gSSBwcm9wb3NlIHRvIHByb2NlZWQgYXMNCmZvbGxvd3M6DQoqIENvbnZlcnQgdGhl IHJlcHJvZHVjZXIgaW50byBhIGJsa3Rlc3RzIHRlc3QgYW5kIHN1Ym1pdCBpcyBhcyBhIHBhdGNo IHRvIHRoZQ0KICBibGt0ZXN0cyBwcm9qZWN0IChodHRwczovL2dpdGh1Yi5jb20vb3NhbmRvdi9i bGt0ZXN0cykuDQoqIFJlbW92ZSB0aGUgbXV0ZXhfbG9jay91bmxvY2soJnN5c2ZzX2xvY2spIGNh bGxzIGZyb20gYmxrX2NsZWFudXBfcXVldWUoKS4NCiAgVGhlc2UgY2FsbHMgYXJlIHVzZWxlc3Mu ICBCbG9jayBkcml2ZXJzIGFyZSByZXF1aXJlZCB0byBjYWxsIGRlbF9nZW5kaXNrKCkNCiAgYmVm b3JlIGNhbGxpbmcgYmxrX2NsZWFudXBfcXVldWUoKS4gVGhhdCBtZWFucyB0aGF0IHN5c2ZzIGF0 dHJpYnV0ZXMgYXJlDQogIHJlbW92ZWQgc3luY2hyb25vdXNseSBiZWZvcmUgYmxrX2NsZWFudXBf cXVldWUoKSBpcyBjYWxsZWQuIFRoZSBmb2xsb3dpbmcNCiAgc3RhdGVtZW50IGluIGJsa19jbGVh bnVwX3F1ZXVlKCkgdmVyaWZpZXMgdGhhdDoNCiAgICBXQVJOX09OX09OQ0UocS0+a29iai5zdGF0 ZV9pbl9zeXNmcyk7DQogIEJUVywgdGhpcyBhbHNvIG1lYW5zIHRoYXQgdGhlIGJsa19xdWV1ZV9k eWluZygpIGNoZWNrcyBpbiB2YXJpb3VzIHNob3cgYW5kDQogIHN0b3JlIG1ldGhvZHMgYXJlIHN1 cGVyZmx1b3VzLg0KKiBJbnRyb2R1Y2UgYSBuZXcgbXV0ZXggdG8gc2VyaWFsaXplIGJsa19tcV9y ZWdpc3Rlcl9kZXYoKSBhbmQNCiAgYmxrX21xX3N5c2ZzX3JlZ2lzdGVyKCkgYW5kIGJsa19tcV9z eXNmc191bnJlZ2lzdGVyKCkuIEkgdGhpbmsgaXQgaXMgd3JvbmcNCiAgdGhhdCB0aGVzZSBmdW5j dGlvbnMgdXNlIHN5c2ZzX211dGV4Lg0KKiBEb2N1bWVudCB0aGUgcHVycG9zZSBvZiBzeXNmc19t dXRleCBpbiBpbmNsdWRlL2xpbnV4L2Jsa2Rldi5oLCBuYW1lbHkgdG8NCiAgc2VyaWFsaXplIHRo ZSBzeXNmcyAuc2hvdygpIGFuZCAuc3RvcmUoKSBjYWxsYmFjayBmdW5jdGlvbnMgYW5kIGFsc28g dG8NCiAgc2VyaWFsaXplIGVsZXZhdG9yIGNoYW5nZXMuDQoNClRoYW5rcywNCg0KQmFydC4NCg0K DQo=