From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jon Rosen (jrosen)" Subject: RE: [RFC PATCH] packet: mark ring entry as in-use inside spin_lock to prevent RX ring overrun Date: Wed, 4 Apr 2018 22:31:49 +0000 Message-ID: References: <20180403215526.15934-1-jrosen@cisco.com> <057239cdf1c34bc69636009c9e099214@XCH-RTP-016.cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Cc: "David S. Miller" , Willem de Bruijn , Eric Dumazet , Kees Cook , David Windsor , "Rosen, Rami" , "Reshetova, Elena" , "Mike Maloney" , Benjamin Poirier , "open list:NETWORKING [GENERAL]" , open list To: Willem de Bruijn Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org PiA+PiA+ICAgIE9uZSBpc3N1ZSB3aXRoIHRoZSBhYm92ZSBwcm9wb3NlZCBjaGFuZ2UgdG8gdXNl IFRQX1NUQVRVU19JTl9QUk9HUkVTUw0KPiA+PiA+ICAgIGlzIHRoYXQgdGhlIGRvY3VtZW50YXRp b24gb2YgdGhlIHRwX3N0YXR1cyBmaWVsZCBpcyBzb21ld2hhdA0KPiA+PiA+ICAgIGluY29uc2lz dGVudC4gIEluIHNvbWUgcGxhY2VzIGl0J3MgZGVzY3JpYmVkIGFzIFRQX1NUQVRVU19LRVJORUwo MCkNCj4gPj4gPiAgICBtZWFuaW5nIHRoZSBlbnRyeSBpcyBvd25lZCBieSB0aGUga2VybmVsIGFu ZCAhVFBfU1RBVFVTX0tFUk5FTCgwKQ0KPiA+PiA+ICAgIG1lYW5pbmcgdGhlIGVudHJ5IGlzIG93 bmVkIGJ5IHVzZXIgc3BhY2UuICBJbiBvdGhlciBwbGFjZXMgb3duZXJzaGlwDQo+ID4+ID4gICAg YnkgdXNlciBzcGFjZSBpcyBkZWZpbmVkIGJ5IHRoZSBUUF9TVEFUVVNfVVNFUigxKSBiaXQgYmVp bmcgc2V0Lg0KPiA+Pg0KPiA+PiBCdXQgaW5kZWVkIHRoaXMgZXhhbXBsZSBpbiBwYWNrZXRfbW1h cC50eHQgaXMgcHJvYmxlbWF0aWMNCj4gPj4NCj4gPj4gICAgIGlmIChzdGF0dXMgPT0gVFBfU1RB VFVTX0tFUk5FTCkNCj4gPj4gICAgICAgICByZXR2YWwgPSBwb2xsKCZwZmQsIDEsIHRpbWVvdXQp Ow0KPiA+Pg0KPiA+PiBJdCBkb2VzIG5vdCByZWFsbHkgbWF0dGVyIHdoZXRoZXIgdGhlIGRvY3Mg YXJlIHBvc3NpYmx5IGluY29uc2lzdGVudCBhbmQNCj4gPj4gd2hpY2ggb25lIGlzIGF1dGhvcml0 YXRpdmUuIEV4YW1wbGVzIGxpa2UgdGhlIGFib3ZlIG1ha2UgaXQgbGlrZWx5IHRoYXQNCj4gPj4g c29tZSB1c2VyIGNvZGUgZXhwZWN0cyBzdWNoIGNvZGUgdG8gd29yay4NCj4gPg0KPiA+IFllcywg dGhhdCdzIGV4YWN0bHkgbXkgY29uY2Vybi4gIFlldCBhbm90aGVyIHRyb3VibGluZyBleGFtcGxl IHNlZW1zIHRvIGJlDQo+ID4gbGlwYmNhcCB3aGljaCBhbHNvIGlzIGxvb2tpbmcgc3BlY2lmaWNh bGx5IGZvciBzdGF0dXMgdG8gYmUgYW55dGhpbmcgb3RoZXIgdGhhbg0KPiA+IFRQX1NUQVRVU19L RVJORUwoMCkgdG8gaW5kaWNhdGUgYSBmcmFtZSBpcyBhdmFpbGFibGUgaW4gdXNlciBzcGFjZS4N Cj4gDQo+IEdvb2QgY2F0Y2guIElmIHBjYXAtbGludXguYyByZWxpZXMgb24gdGhpcyB0aGVuIHRo ZSBzdGF0dXMgZmllbGQNCj4gY2Fubm90IGJlIGNoYW5nZWQuIE90aGVyIGZpZWxkcyBjYW4gYmUg bW9kaWZpZWQgZnJlZWx5IHdoaWxlIHRwX3N0YXR1cw0KPiByZW1haW5zIDAsIHBlcmhhcHMgdGhh dCdzIGFuIG9wdGlvbi4NCg0KUG9zc2libHkuIFNvbWVvbmUgZWxzZSBzdWdnZXN0ZWQgc29tZXRo aW5nIHNpbWlsYXIgYnV0IGluIGF0IGxlYXN0IHRoZQ0Kb25lIGV4YW1wbGUgd2UgdGhvdWdodCB0 aHJvdWdoIGl0IHN0aWxsIHNlZW1lZCBsaWtlIGl0IGRpZG4ndCBhZGRyZXNzIHRoZSBwcm9ibGVt Lg0KDQpGb3IgZXhhbXBsZSwgbGV0J3Mgc2F5IHdlIHVzZWQgdHBfbGVuID09IC0xIHRvIGluZGlj YXRlIHRvIG90aGVyIGtlcm5lbCB0aHJlYWRzDQp0aGF0IHRoZSBlbnRyeSB3YXMgYWxyZWFkeSBp biBwcm9ncmVzcy4gIFRoaXMgd291bGQgcmVxdWlyZSB0aGF0IHVzZXIgc3BhY2UgbmV2ZXINCnNl dCB0cF9sZW4gPSAtMSBiZWZvcmUgcmV0dXJuaW5nIHRoZSBlbnRyeSBiYWNrIHRvIHRoZSBrZXJu ZWwuICBJZiBpdCBkaWQgdGhlbiBubw0Ka2VybmVsIHRocmVhZCB3b3VsZCBldmVyIGNsYWltIG93 bmVyc2hpcCBhbmQgdGhlIHJpbmcgd291bGQgaGFuZy4NCg0KTm93LCBpdCBzZWVtcyBwcmV0dHkg dW5saWtlbHkgdGhhdCB1c2VyIHNwYWNlIHdvdWxkIGRvIHN1Y2ggYSB0aGluZyBzbyBtYXliZSB3 ZQ0KY291bGQgbG9vayBwYXN0IHRoYXQsIGJ1dCB0aGVuIHdlIHJ1biBpbnRvIHRoZSBpc3N1ZSB0 aGF0IHRoZXJlIGlzIHN0aWxsIGEgd2luZG93DQpvZiBvcHBvcnR1bml0eSBmb3Igb3RoZXIga2Vy bmVsIHRocmVhZHMgdG8gY29tZSBpbiBhbmQgd3JhcCB0aGUgcmluZy4NCg0KVGhlIHJlYXNvbiBp cyB3ZSBjYW4ndCBzZXQgdHBfbGVuIHRvIHRoZSBjb3JyZWN0IGxlbmd0aCBhZnRlciBzZXR0aW5n IHRwX3N0YXR1cyBiZWNhdXNlDQp1c2VyIHNwYWNlIGNvdWxkIGdyYWIgdGhlIGVudHJ5IGFuZCBz ZWUgdHBfbGVuID09IC0xIHNvIHdlIGhhdmUgdG8gc2V0IHRwX2xlbg0KYmVmb3JlIHdlIHNldCB0 cF9zdGF0dXMuIFRoaXMgbWVhbnMgdGhhdCB0aGVyZSBpcyBzdGlsbCBhIHdpbmRvdyB3aGVyZSBv dGhlcg0Ka2VybmVsIHRocmVhZHMgY291bGQgY29tZSBpbiBhbmQgc2VlIHRwX2xlbiBhcyBzb21l dGhpbmcgb3RoZXIgdGhhbiAtMSBhbmQNCmEgdHBfc3RhdHVzIG9mIFRQX1NUQVRVU19LRVJORUwg YW5kIHRoaW5rIGl0J3Mgb2sgdG8gYWxsb2NhdGUgdGhlIGVudHJ5Lg0KVGhpcyBwdXRzIHVzIGJh Y2sgdG8gd2hlcmUgd2UgYXJlIHRvZGF5IChhcmd1YWJseSB3aXRoIGEgc21hbGxlciB3aW5kb3cs DQpidXQgYSB3aW5kb3cgbm9uZSB0aGUgbGVzcykuDQoNCkFsdGVybmF0aXZlbHkgd2UgY291bGQg cmVhY3F1aXJlIHRoZSBzcGluX2xvY2sgdG8gdGhlbiBzZXQgdHBfbGVuIGZvbGxvd2VkIGJ5DQp0 cF9zdGF0dXMuICBUaGlzIHdvdWxkIGdpdmUgdGhlIG5lY2Vzc2FyeSBpbmRpdmlzaWJpbGl0eSBp biB0aGUga2VybmVsIHdoaWxlIA0KcHJlc2VydmluZyBwcm9wZXIgb3JkZXIgYXMgbWFkZSB2aXNp YmxlIHRvIHVzZXIgc3BhY2UsIGJ1dCBpdCBjb21lcyBhdCB0aGUgY29zdA0Kb2YgYW5vdGhlciBz cGluX2xvY2suDQoNClRoYW5rcyBmb3IgdGhlIHN1Z2dlc3Rpb24uICBJZiB5b3UgY2FuIHRoaW5r IG9mIGEgd2F5IGFyb3VuZCB0aGlzIEknbSBhbGwgZWFycy4NCkknbGwgdGhpbmsgb24gdGhpcyBz b21lIG1vcmUgYnV0IHNvIGZhciBJJ20gc3R1Y2sgb24gaG93IHRvIGdldCBwYXN0IGhhdmluZyB0 bw0KYnJvYWRlbiB0aGUgc2NvcGUgb2YgdGhlIHNwaW5fbG9jaywgcmVhY3F1aXJlIHRoZSBzcGlu X2xvY2ssIG9yIHVzZSBzb21lIHNvcnQNCm9mIGF0b21pYyBjb25zdHJ1Y3QgYWxvbmcgd2l0aCBh IHBhcmFsbGVsIHNoYWRvdyByaW5nIHN0cnVjdHVyZSAoc3RpbGwgdGhpbmtpbmcNCnRocm91Z2gg dGhhdCBvbmUgYXMgd2VsbCkuDQoNCg==