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McKenney" , "roman.gushchin@linux.dev" Subject: RE: Question about the barrier() in hlist_nulls_for_each_entry_rcu() Thread-Topic: Question about the barrier() in hlist_nulls_for_each_entry_rcu() Thread-Index: AQHZu+cDW9UBwZmf30GL9p6MGC4yBq/EWe3Q Date: Fri, 21 Jul 2023 15:59:38 +0000 Message-ID: <962bb2b940e64e7da7b71d11b307defc@AcuMS.aculab.com> References: <1E0741E0-2BD9-4FA3-BA41-4E83315A10A8@joelfernandes.org> <1AF98387-B78C-4556-BE2E-E8F88ADACF8A@gmail.com> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Li4uLg0KPiBSaWdodCwgaXQgc2hvdWxkbid0IG5lZWQgdG8gY2FjaGUuIFRvIEVyaWMncyBwb2lu dCBpdCBtaWdodCBiZSByaXNreSB0byByZW1vdmUNCj4gdGhlIGJhcnJpZXIoKSBhbmQgc29tZW9u ZSBuZWVkcyB0byBleHBsYWluIHRoYXQgaXNzdWUgZmlyc3QgKG9yIElNTyB0aGVyZSBuZWVkcw0K PiB0byBiZSBhbm90aGVyIHRhbmdpYmxlIHJlYXNvbiBsaWtlIHBlcmZvcm1hbmNlIGV0YykuIEFu eXdheSwgRldJVyBJIHdyb3RlIGENCj4gc2ltcGxlIHByb2dyYW0gYW5kIEkgYW0gbm90IHNlZWlu ZyB0aGUgaGVhZC0+Zmlyc3QgY2FjaGVkIHdpdGggdGhlIHBhdHRlcm4geW91DQo+IHNoYXJlZCBh Ym92ZToNCj4gDQo+ICNpbmNsdWRlIDxzdGRsaWIuaD4NCj4gDQo+ICNkZWZpbmUgUkVBRF9PTkNF KHgpICgqKHZvbGF0aWxlIHR5cGVvZih4KSAqKSYoeCkpDQo+ICNkZWZpbmUgYmFycmllcigpIF9f YXNtX18gX192b2xhdGlsZV9fKCIiOiA6IDoibWVtb3J5IikNCj4gDQo+IHR5cGVkZWYgc3RydWN0 IGxpc3RfaGVhZCB7DQo+ICAgICAgaW50IGZpcnN0Ow0KPiAgICAgIHN0cnVjdCBsaXN0X2hlYWQg Km5leHQ7DQo+IH0gbGlzdF9oZWFkOw0KPiANCj4gaW50IG1haW4oKSB7DQo+ICAgICAgbGlzdF9o ZWFkICpoZWFkID0gKGxpc3RfaGVhZCAqKW1hbGxvYyhzaXplb2YobGlzdF9oZWFkKSk7DQo+ICAg ICAgaGVhZC0+Zmlyc3QgPSAxOw0KPiAgICAgIGhlYWQtPm5leHQgPSAwOw0KPiANCj4gICAgICBS RUFEX09OQ0UoaGVhZC0+Zmlyc3QpOw0KPiAgICAgIGJhcnJpZXIoKTsNCj4gICAgICBSRUFEX09O Q0UoaGVhZC0+Zmlyc3QpOw0KPiANCj4gICAgICBmcmVlKGhlYWQpOw0KPiAgICAgIHJldHVybiAw Ow0KPiB9DQoNCllvdSBwcm9iYWJseSBuZWVkIHRvIHRyeSBoYXJkZXIgdG8gZ2VuZXJhdGUgdGhl IGVycm9yLg0KSXQgcHJvYmFibHkgaGFzIHNvbWV0aGluZyB0byBkbyBjb2RlIHN1cnJvdW5kaW5n IHRoZQ0Kc2tfbnVsbHNfZm9yX2VhY2hfcmN1KCkgaW4gdGhlIGNhMDY1ZDBjXiB2ZXJzaW9uIG9m IHVkcC5jLg0KDQpUaGF0IHBhdGNoIHJlbW92ZXMgdGhlIHJldHJ5IGxvb3AgLSBhbmQgcHJvYmFi bHkgYnJlYWtzIHVkcCByZWNlaXZlLg0KVGhlIGlzc3VlIGlzIHRoYXQgc29ja2V0cyBjYW4gYmUg bW92ZWQgYmV0d2VlbiB0aGUgJ2hhc2gyJyBjaGFpbnMNCihlZyBieSBjb25uZWN0KCkpIHdpdGhv dXQgYmVpbmcgZnJlZWQuDQoNCglEYXZpZA0KDQotDQpSZWdpc3RlcmVkIEFkZHJlc3MgTGFrZXNp ZGUsIEJyYW1sZXkgUm9hZCwgTW91bnQgRmFybSwgTWlsdG9uIEtleW5lcywgTUsxIDFQVCwgVUsN ClJlZ2lzdHJhdGlvbiBObzogMTM5NzM4NiAoV2FsZXMpDQo=