Return-Path: linux-nfs-owner@vger.kernel.org Received: from exprod6og114.obsmtp.com ([64.18.1.33]:55797 "HELO exprod6og114.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1759162Ab1LOR15 (ORCPT ); Thu, 15 Dec 2011 12:27:57 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Subject: RE: copy offload support in Linux - new system call needed? Date: Thu, 15 Dec 2011 12:27:55 -0500 Message-ID: In-Reply-To: <1323968015.14317.28.camel@lade.trondhjem.org> References: <4EE8F75F.6070800@gmail.com> <20111214192739.GN2203@ZenIV.linux.org.uk> <4EE8FC2E.3010207@gmail.com> <20111214222723.GD7623@fieldses.org> <1323961140.14317.2.camel@lade.trondhjem.org> <1323965498.14317.13.camel@lade.trondhjem.org> <1323968015.14317.28.camel@lade.trondhjem.org> From: "Loke, Chetan" To: "Trond Myklebust" Cc: "J. Bruce Fields" , "Ric Wheeler" , "Al Viro" , , "linux-fsdevel" , "Hannes Reinecke" , "Andrew Morton" , , "Joel Becker" , "James Bottomley" Sender: linux-nfs-owner@vger.kernel.org List-ID: PiA+IHZpcnR1YWxpemF0aW9uIHZlbmRvcnMgd2hvIHN1cHBvcnQgdGhpcyBvZmZsb2FkIGRvIGl0 IGF0IGEgbGF5ZXINCj4gYWJvdmUgdGhlIGd1ZXN0LU9TKEludHJhLUxVTih0bSkgbG9ja2luZyBv ciB3aGF0ZXZlciBmYW5jeSBsb2NraW5nKS4gU28NCj4gSSB0aGluayAnY29weWZpbGUnIGlzIGdv aW5nIHRvIGJlIGFwcGVhbGluZyB0byBhcHBsaWNhdGlvbi1kZXZlbG9wZXJzDQo+IG1vcmUgdGhh biB0aGUgaHlwZXJ2aXNvci12ZW5kb3JzLg0KPiANCj4gVGhlIGFwcGxpY2F0aW9uIGlzIHRoaW4g cHJvdmlzaW9uaW5nLCBub3QgdGhlICdjcCcgY29tbWFuZC4gV2hlbg0KDQoNCnRoaW4tcHJvdmlz aW9uaW5nIGlzIG9uZSB1c2UtY2FzZS4gVGhlcmUgYXJlIHF1aXRlIGEgZmV3IHVzZS1jYXNlcyBv ZiAnY29weWZpbGUnIGRlcGVuZGluZyBvbiB5b3VyIGJ1c2luZXNzLWxvZ2ljIGFuZCB0aGUgdHlw ZSBvZiBhcHBsaWFuY2UgeW91IHNlbGwuDQoNCg0KPiB2aXJ0dWFsaXNhdGlvbiB2ZW5kb3JzIGRv IHN1cHBvcnQgdGhpcywgaXQgd2lsbCBtYWlubHkgYmUgYXMgcGFydCBvZg0KPiB0aGVpciBpbWFn ZSBtYW5hZ2VtZW50IHRvb2xraXRzLCBub3QgdGhlIGh5cGVydmlzb3IuDQo+IA0KDQpUb29sa2l0 cz8gTWF5IG5vdCBiZSB0cnVlLiBUaGUgdG9vbGtpdCBtaWdodCBuZWVkIHRvIHRhbGsgdG8gc29t ZSBoeXBlcnZpc29yLWNvbXBvbmVudCB0byBlbnN1cmUgTFVOLWxvY2tpbmcgZXRjIG9uIHRoZSB0 YXJnZXQuIFNvIHRoaXMgaXMgbm90IGVudGlyZWx5IGlzb2xhdGVkIGFzIHlvdSBtaWdodCB0aGlu ay4gVGhlcmUgaXMgc29tZSBpbnRlZ3JhdGlvbi4gQXMgYW4gZXhhbXBsZShqdXN0IHRvIHByb3Zl IHRoZSBwb2ludCkgLSBIYXZlIHlvdSBldmVyIHNlZW4gYW55b25lIG5vdCB1c2UgdnNwaGVyZS1j bGllbnQgb24gVk13YXJlIGZvciBjb3B5aW5nIFZNIHRlbXBsYXRlcz8NCg0KDQo+ID4gU28gbGV0 J3MgdGhpbmsgYWJvdXQgaXQgZnJvbSBlbmQtdXNlcnMgcGVyc3BlY3RpdmU6DQo+ID4gV29uJ3Qg ZXZlcnlvbmUgcmVwbGljYXRlIGNvZGUgdG8gY2hlY2sgLSAnQW0gSSBkb25lJz8gSXQgd2lsbCBq dXN0DQo+IG1ha2UgYXBwbGljYXRpb24gZm9sa3Mgd3JpdGUgbW9yZSAodWdseSljb2RlLiBCZWNh dXNlIHlvdSB3b3VsZCB0aGVuDQo+IGhhdmUgdG8gbWFpbnRhaW4gYW5vdGhlciBxdWV1ZS9ldGMg dG8gY2hlY2sgZm9yIHRoaXMgb3BlcmF0aW9uLg0KPiANCj4gJ0FtIEkgZG9uZScgaXMgZWFzeTog Y29weWZpbGUoKSByZXR1cm5zIHdpdGggdGhlIG51bWJlciBvZiBieXRlcyB0aGF0DQo+IGhhdmUg YmVlbiBjb3BpZWQuDQo+IA0KPiAnSXMgbXkgY29weWZpbGUoKSBzeXNjYWxsIG1ha2luZyBwcm9n cmVzcycgaXMgdGhlIHF1ZXN0aW9uIHRoYXQgbmVlZHMNCj4gYW5zd2VyaW5nLg0KPiANCg0KVW5k ZXJzdG9vZC4gQnV0IGFzIGEgdXNlciwgd2UgZG9uJ3Qga25vdyB3aGF0ICdhbSBJIGRvbmUnIGlz IGdvaW5nIHRvIHJlcG9ydC4NCg0KJ2FtIEkgZG9uZScgY2FuIHJldHVybjoNCjEpQUNLW2NvcHkg ZG9uZV0gLSBzaW1wbGlzdGljIGNhc2UuDQoyKUlOLXByb2dyZXNzLg0KMylOQUNLW2NvcHkgZmFp bGVkKHdpdGggc3RhdHVzIHZhbHVlcykgb3IgY29weSBwYXJ0aWFsbHkgY29tcGxldGVkXQ0KDQpB bmQgaWYgeW91IGFyZSB1c2luZyB0aGUgY29weS1WTSB1c2UtY2FzZSB0aGVuIHZlcnkgZmV3IFZN cyBhcmUgdW5kZXIgNEdCcy4gU28gd2Ugd2lsbCBoaXQgMikgYWJvdmUgbW9yZSBmcmVxdWVudGx5 IHRoYW4gMSkgYW5kIDMpLg0KDQoNCj4gPiBXZSBjYW4ganVzdCBzdXBwb3J0IGZ1bGwtY29weS4g UGFydGlhbCBjb3BpZXMgY2FuIGJlIHJldHVybmVkIGFzDQo+IGZhaWx1cmUuDQo+IA0KPiBUaGVu IHlvdSBoYXZlIHRvIGNoZWNrIHRoZSBlbnRpcmUgcmFuZ2Ugb24gZXJyb3IgaW5zdGVhZCBvZiBq dXN0DQo+IHJlc3VtaW5nIHRoZSBjb3B5IGZyb20gd2hlcmUgaXQgc3RvcHBlZC4NCj4gDQoNCldo eSBub3QgcmVzdGFydD8gV2hhdCBpZiB0aGUgTFVOIHdhcyBpbXBsZW1lbnRpbmcgdGhpbi1wcm92 aXNpb25pbmcgYW5kIG5vdyBpdCByYW4gb3V0LW9mLXNwYWNlIGFmdGVyIHBhcnRpYWxseSBjb3B5 aW5nIHlvdXIgZGF0YS4NClNvIHdoeSBub3QgcmVzdGFydCB0aGUgY29weT8gSWYgdGhlIHRhcmdl dCBkb2Vzbid0IHN1cHBvcnQgYXV0by1leHRlbmQsIHNvbWVvbmUoc3RvcmFnZS1hZG1pbiBldGMp IHdvdWxkIGhhdmUgdG8gc3RlcC1pbiBhbmQgbWFuYWdlIHRoYXQgTFVOLg0KWW91IG1pZ2h0IGFz LXdlbGwgcmVzdGFydCB0aGUgY29weSBpbiB0aGlzIGNhc2UuDQoNCg0KDQpDaGV0YW4gTG9rZQ0K DQoNCg==