From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40767C11D0B for ; Thu, 20 Feb 2020 14:24:04 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1B0EE207FD for ; Thu, 20 Feb 2020 14:24:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B0EE207FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1j4mju-0003Cv-Rm; Thu, 20 Feb 2020 14:23:42 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1j4mjt-0003Cq-Gu for xen-devel@lists.xenproject.org; Thu, 20 Feb 2020 14:23:41 +0000 X-Inumbo-ID: 972a8e4c-53ec-11ea-8540-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 972a8e4c-53ec-11ea-8540-12813bfff9fa; Thu, 20 Feb 2020 14:23:40 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 7C76DB1B8; Thu, 20 Feb 2020 14:23:39 +0000 (UTC) To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Jan Beulich References: <20200220120231.86907-1-roger.pau@citrix.com> <20200220141117.GK4679@Air-de-Roger> From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= Message-ID: Date: Thu, 20 Feb 2020 15:23:38 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200220141117.GK4679@Air-de-Roger> Content-Language: en-US Subject: Re: [Xen-devel] [PATCH] rwlock: allow recursive read locking when already locked in write mode X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Julien Grall , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , xen-devel@lists.xenproject.org Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" T24gMjAuMDIuMjAgMTU6MTEsIFJvZ2VyIFBhdSBNb25uw6kgd3JvdGU6Cj4gT24gVGh1LCBGZWIg MjAsIDIwMjAgYXQgMDE6NDg6NTRQTSArMDEwMCwgSmFuIEJldWxpY2ggd3JvdGU6Cj4+IE9uIDIw LjAyLjIwMjAgMTM6MDIsIFJvZ2VyIFBhdSBNb25uZSB3cm90ZToKPj4+IEkndmUgZG9uZSBzb21l IHRlc3RpbmcgYW5kIGF0IGxlYXN0IHRoZSBDUFUgZG93biBjYXNlIGlzIGZpeGVkIG5vdy4KPj4+ IFBvc3RpbmcgZWFybHkgaW4gb3JkZXIgdG8gZ2V0IGZlZWRiYWNrIG9uIHRoZSBhcHByb2FjaCB0 YWtlbi4KPj4KPj4gTG9va3MgZ29vZCwgdGhhbmtzLCBqdXN0IGEgcXVlc3Rpb24gYW5kIHR3byBj b21tZW50czoKPj4KPj4+IC0tLSBhL3hlbi9pbmNsdWRlL3hlbi9yd2xvY2suaAo+Pj4gKysrIGIv eGVuL2luY2x1ZGUveGVuL3J3bG9jay5oCj4+PiBAQCAtMjAsMjEgKzIwLDMwIEBAIHR5cGVkZWYg c3RydWN0IHsKPj4+ICAgI2RlZmluZSBERUZJTkVfUldMT0NLKGwpIHJ3bG9ja190IGwgPSBSV19M T0NLX1VOTE9DS0VECj4+PiAgICNkZWZpbmUgcndsb2NrX2luaXQobCkgKCoobCkgPSAocndsb2Nr X3QpUldfTE9DS19VTkxPQ0tFRCkKPj4+ICAgCj4+PiAtLyoKPj4+IC0gKiBXcml0ZXIgc3RhdGVz ICYgcmVhZGVyIHNoaWZ0IGFuZCBiaWFzLgo+Pj4gLSAqCj4+PiAtICogV3JpdGVyIGZpZWxkIGlz IDggYml0IHRvIGFsbG93IGZvciBwb3RlbnRpYWwgb3B0aW1pc2F0aW9uLCBzZWUKPj4+IC0gKiBf d3JpdGVfdW5sb2NrKCkuCj4+PiAtICovCj4+PiAtI2RlZmluZSAgICBfUVdfV0FJVElORyAgMSAg ICAgICAgICAgICAgIC8qIEEgd3JpdGVyIGlzIHdhaXRpbmcgICAgICovCj4+PiAtI2RlZmluZSAg ICBfUVdfTE9DS0VEICAgMHhmZiAgICAgICAgICAgIC8qIEEgd3JpdGVyIGhvbGRzIHRoZSBsb2Nr ICovCj4+PiAtI2RlZmluZSAgICBfUVdfV01BU0sgICAgMHhmZiAgICAgICAgICAgIC8qIFdyaXRl ciBtYXNrLiovCj4+PiAtI2RlZmluZSAgICBfUVJfU0hJRlQgICAgOCAgICAgICAgICAgICAgIC8q IFJlYWRlciBjb3VudCBzaGlmdCAgICAgICovCj4+PiArLyogV3JpdGVyIHN0YXRlcyAmIHJlYWRl ciBzaGlmdCBhbmQgYmlhcy4gKi8KPj4+ICsjZGVmaW5lICAgIF9RV19XQUlUSU5HICAxICAgICAg ICAgICAgICAgICAgICAgICAvKiBBIHdyaXRlciBpcyB3YWl0aW5nICovCj4+PiArI2RlZmluZSAg ICBfUVdfTE9DS0VEICAgMyAgICAgICAgICAgICAgICAgICAgICAgLyogQSB3cml0ZXIgaG9sZHMg dGhlIGxvY2sgKi8KPj4KPj4gQWl1aSB0aGluZ3Mgd291bGQgd29yayBlcXVhbGx5IHdlbGwgaWYg MiB3YXMgdXNlZCBoZXJlPwo+IAo+IEkgdGhpbmsgc28sIEkgbGVmdCBpdCBhcyAzIGJlY2F1c2Ug cHJldmlvdXNseSBMT0NLRUQgd291bGQgYWxzbwo+IGluY2x1ZGUgV0FJVElORywgYW5kIEkgZGlk bid0IHdhbnQgdG8gY2hhbmdlIGl0IGluIGNhc2UgSSd2ZSBtaXNzZWQKPiBzb21lIGNvZGUgcGF0 aCB0aGF0IHdhcyByZWx5aW5nIG9uIHRoYXQuCj4gCj4+Cj4+PiArI2RlZmluZSAgICBfUVdfV01B U0sgICAgMyAgICAgICAgICAgICAgICAgICAgICAgLyogV3JpdGVyIG1hc2sgKi8KPj4+ICsjZGVm aW5lICAgIF9RV19DUFVTSElGVCAyICAgICAgICAgICAgICAgICAgICAgICAvKiBXcml0ZXIgQ1BV IHNoaWZ0ICovCj4+PiArI2RlZmluZSAgICBfUVdfQ1BVTUFTSyAgMHgzZmZjICAgICAgICAgICAg ICAgICAgLyogV3JpdGVyIENQVSBtYXNrICovCj4+Cj4+IEF0IGxlYXN0IG9uIHg4NiwgdGhlIHNo aWZ0IGludm9sdmVkIGhlcmUgaXMgcXVpdGUgY2VydGFpbmx5Cj4+IG1vcmUgZXhwZW5zaXZlIHRo YW4gdXNpbmcgd2lkZXIgaW1tZWRpYXRlcyBvbiBBTkQgYW5kIENNUAo+PiByZXN1bHRpbmcgZnJv bSB0aGUgX1FXX01BU0stYmFzZWQgY29tcGFyaXNvbnMuIEknZCB0aGVyZWZvcmUKPj4gbGlrZSB0 byBzdWdnZXN0IHRvIHB1dCB0aGUgQ1BVIGluIHRoZSBsb3cgMTIgYml0cy4KPiAKPiBIbSByaWdo dC4gVGhlIExPQ0tFRCBhbmQgV0FJVElORyBiaXRzIGRvbid0IG5lZWQgc2hpZnRpbmcgYW55d2F5 Lgo+IAo+Pgo+PiBBbm90aGVyIG9wdGlvbiBpcyB0byB1c2UgdGhlIHJlY3Vyc2VfY3B1IGZpZWxk IG9mIHRoZQo+PiBhc3NvY2lhdGVkIHNwaW4gbG9jazogVGhlIGZpZWxkIGlzIHVzZWQgZm9yIHJl Y3Vyc2l2ZSBsb2Nrcwo+PiBvbmx5LCBhbmQgaGVuY2UgdGhlIG9ubHkgY29uZmxpY3Qgd291bGQg YmUgd2l0aAo+PiBfc3Bpbl9pc19sb2NrZWQoKSwgd2hpY2ggd2UgZG9uJ3QgKGFuZCBpbiB0aGUg ZnV0dXJlIHRoZW4KPj4gYWxzbyBzaG91bGRuJ3QpIHVzZSBvbiB0aGlzIGxvY2suCj4gCj4gSSBs b29rZWQgaW50byB0aGF0IGFsc28sIGJ1dCB0aGluZ3MgZ2V0IG1vcmUgY29tcGxpY2F0ZWQgQUZB SUNULCBhcyBpdCdzCj4gbm90IHBvc3NpYmxlIHRvIGF0b21pY2FsbHkgZmV0Y2ggdGhlIHN0YXRl IG9mIHRoZSBsb2NrIGFuZCB0aGUgb3duZXIKPiBDUFUgYXQgdGhlIHNhbWUgdGltZS4gTmVpdGhl ciB5b3UgY291bGQgc2V0IHRoZSBMT0NLRUQgYml0IGFuZCB0aGUgQ1BVCj4gYXQgdGhlIHNhbWUg dGltZS4KPiAKPj4KPj4+IEBAIC0xNjYsNyArMTgwLDggQEAgc3RhdGljIGlubGluZSB2b2lkIF93 cml0ZV91bmxvY2socndsb2NrX3QgKmxvY2spCj4+PiAgICAgICAgKiBJZiB0aGUgd3JpdGVyIGZp ZWxkIGlzIGF0b21pYywgaXQgY2FuIGJlIGNsZWFyZWQgZGlyZWN0bHkuCj4+PiAgICAgICAgKiBP dGhlcndpc2UsIGFuIGF0b21pYyBzdWJ0cmFjdGlvbiB3aWxsIGJlIHVzZWQgdG8gY2xlYXIgaXQu Cj4+PiAgICAgICAgKi8KPj4+IC0gICAgYXRvbWljX3N1YihfUVdfTE9DS0VELCAmbG9jay0+Y250 cyk7Cj4+PiArICAgIEFTU0VSVChfaXNfd3JpdGVfbG9ja2VkX2J5X21lKGF0b21pY19yZWFkKCZs b2NrLT5jbnRzKSkpOwo+Pj4gKyAgICBhdG9taWNfc3ViKF93cml0ZV9sb2NrX3ZhbCgpLCAmbG9j ay0+Y250cyk7Cj4+Cj4+IEkgdGhpbmsgdGhpcyB3b3VsZCBiZSBtb3JlIGVmZmljaWVudCB3aXRo IGF0b21pY19hbmQoKSwgbm90Cj4+IHRoZSBsZWFzdCBiZWNhdXNlIG9mIHRoZSB0aGVuIGF2b2lk ZWQgc21wX3Byb2Nlc3Nvcl9pZCgpLgo+PiBXaGV0aGVyIHRvIG1hc2sgb2ZmIGp1c3QgX1FXX1dN QVNLIG9yIGFsc28gdGhlIENQVSBudW1iZXIgb2YKPj4gdGhlIGxhc3Qgd3JpdGUgb3duZXIgd291 bGQgbmVlZCB0byBiZSBkZXRlcm1pbmVkLiBCdXQgd2l0aAo+PiB1c2luZyBzdWJ0cmFjdGlvbiwg aW4gY2FzZSBvZiBwcm9ibGVtcyBpdCdsbCBsaWtlbHkgYmUKPj4gaGFyZGVyIHRvIHVuZGVyc3Rh bmQgd2hhdCBhY3R1YWxseSB3ZW50IG9uLCBmcm9tIGxvb2tpbmcgYXQKPj4gdGhlIHJlc3VsdGlu ZyBzdGF0ZSBvZiB0aGUgbG9jayAodGhpcyBpcyBpbiBwYXJ0IGEgcHJlLQo+PiBleGlzdGluZyBw cm9ibGVtLCBidXQgZ2V0cyB3b3JzZSB3aXRoIHN1YnRyYWN0aW9uIG9mIENQVQo+PiBudW1iZXJz KS4KPiAKPiBSaWdodCwgYSBtYXNrIHdvdWxkIGJlIGJldHRlci4gUmlnaHQgbm93IGJvdGggbmVl ZCB0byBiZSBjbGVhcmVkICh0aGUKPiBMT0NLRUQgYW5kIHRoZSBDUFUgZmllbGRzKSBhcyB0aGVy ZSdzIGNvZGUgdGhhdCByZWxpZXMgb24gIWxvY2stPmNudHMKPiBhcyBhIHdheSB0byBkZXRlcm1p bmUgdGhhdCB0aGUgbG9jayBpcyBub3QgcmVhZCBvciB3cml0ZSBsb2NrZWQuIElmIHdlCj4gbGVm dCB0aGUgQ1BVIGx5aW5nIGFyb3VuZCB0aG9zZSBjaGVja3Mgd291bGQgbmVlZCB0byBiZSBhZGp1 c3RlZC4KCkluIGNhc2UgeW91IG1ha2UgX1FSX1NISUZUIDE2IGl0IGlzIHBvc3NpYmxlIHRvIGp1 c3Qgd3JpdGUgYSAyLWJ5dGUgemVybwp2YWx1ZSBmb3Igd3JpdGVfdW5sb2NrKCkgKGxpa2UgaXRz IHBvc3NpYmxlIHRvIGRvIHNvIHRvZGF5IHVzaW5nIGEKc2luZ2xlIGJ5dGUgd3JpdGUpLgoKCkp1 ZXJnZW4KCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fClhl bi1kZXZlbCBtYWlsaW5nIGxpc3QKWGVuLWRldmVsQGxpc3RzLnhlbnByb2plY3Qub3JnCmh0dHBz Oi8vbGlzdHMueGVucHJvamVjdC5vcmcvbWFpbG1hbi9saXN0aW5mby94ZW4tZGV2ZWw=