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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 1j58U8-00029W-LN; Fri, 21 Feb 2020 13:36:52 +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 1j58U7-00029R-OA for xen-devel@lists.xenproject.org; Fri, 21 Feb 2020 13:36:51 +0000 X-Inumbo-ID: 36c1a338-54af-11ea-8660-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 36c1a338-54af-11ea-8660-12813bfff9fa; Fri, 21 Feb 2020 13:36:50 +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 CD789B18D; Fri, 21 Feb 2020 13:36:49 +0000 (UTC) To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= References: <20200220173116.88915-1-roger.pau@citrix.com> <83d48223-21eb-be54-985c-085449661892@xen.org> <20200221091005.GT4679@Air-de-Roger> From: Jan Beulich Message-ID: Date: Fri, 21 Feb 2020 14:36:52 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200221091005.GT4679@Air-de-Roger> Content-Language: en-US Subject: Re: [Xen-devel] [PATCH v2] 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: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= , Stefano Stabellini , Julien Grall , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , xen-devel@lists.xenproject.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" T24gMjEuMDIuMjAyMCAxMDoxMCwgUm9nZXIgUGF1IE1vbm7DqSB3cm90ZToKPiBPbiBUaHUsIEZl YiAyMCwgMjAyMCBhdCAwNzoyMDowNlBNICswMDAwLCBKdWxpZW4gR3JhbGwgd3JvdGU6Cj4+IEhp LAo+Pgo+PiBPbiAyMC8wMi8yMDIwIDE3OjMxLCBSb2dlciBQYXUgTW9ubmUgd3JvdGU6Cj4+PiBB bGxvdyBhIENQVSBhbHJlYWR5IGhvbGRpbmcgdGhlIGxvY2sgaW4gd3JpdGUgbW9kZSB0byBhbHNv IGxvY2sgaXQgaW4KPj4+IHJlYWQgbW9kZS4gVGhlcmUncyBubyBoYXJtIGluIGFsbG93aW5nIHJl YWQgbG9ja2luZyBhIHJ3bG9jayB0aGF0J3MKPj4+IGFscmVhZHkgb3duZWQgYnkgdGhlIGNhbGxl ciAoaWU6IENQVSkgaW4gd3JpdGUgbW9kZS4gQWxsb3dpbmcgc3VjaAo+Pj4gYWNjZXNzZXMgaXMg cmVxdWlyZWQgYXQgbGVhc3QgZm9yIHRoZSBDUFUgbWFwcyB1c2UtY2FzZS4KPj4+Cj4+PiBJbiBv cmRlciB0byBkbyB0aGlzIHJlc2VydmUgMTRiaXRzIG9mIHRoZSBsb2NrLCB0aGlzIGFsbG93cyB0 byBzdXBwb3J0Cj4+PiB1cCB0byAxNjM4NCBDUFVzLiBBbHNvIHJlZHVjZSB0aGUgd3JpdGUgbG9j ayBtYXNrIHRvIDIgYml0czogb25lIHRvCj4+PiBzaWduYWwgdGhlcmUgYXJlIHBlbmRpbmcgd3Jp dGVycyB3YWl0aW5nIG9uIHRoZSBsb2NrIGFuZCB0aGUgb3RoZXIgdG8KPj4+IHNpZ25hbCB0aGUg bG9jayBpcyBvd25lZCBpbiB3cml0ZSBtb2RlLiBOb3RlIHRoZSB3cml0ZSByZWxhdGVkIGRhdGEK Pj4+IGlzIHVzaW5nIDE2Yml0cywgdGhpcyBpcyBkb25lIGluIG9yZGVyIHRvIGJlIGFibGUgdG8g Y2xlYXIgaXQgKGFuZAo+Pj4gdGh1cyByZWxlYXNlIHRoZSBsb2NrKSB1c2luZyBhIDE2Yml0IGF0 b21pYyB3cml0ZS4KPj4+Cj4+PiBUaGlzIHJlZHVjZXMgdGhlIG1heGltdW0gbnVtYmVyIG9mIGNv bmN1cnJlbnQgcmVhZGVycyBmcm9tIDE2Nzc3MjE2IHRvCj4+PiA2NTUzNiwgSSB0aGluayB0aGlz IHNob3VsZCBzdGlsbCBiZSBlbm91Z2gsIG9yIGVsc2UgdGhlIGxvY2sgZmllbGQKPj4+IGNhbiBi ZSBleHBhbmRlZCBmcm9tIDMyIHRvIDY0Yml0cyBpZiBhbGwgYXJjaGl0ZWN0dXJlcyBzdXBwb3J0 IGF0b21pYwo+Pj4gb3BlcmF0aW9ucyBvbiA2NGJpdCBpbnRlZ2Vycy4KPj4KPj4gRldJVywgYXJt MzIgaXMgYWJsZSB0byBzdXBwb3J0IGF0b21pYyBvcGVyYXRpb25zIG9uIDY0LWJpdCBpbnRlZ2Vy cy4KPj4KPj4+ICAgc3RhdGljIGlubGluZSB2b2lkIF93cml0ZV91bmxvY2socndsb2NrX3QgKmxv Y2spCj4+PiAgIHsKPj4+IC0gICAgLyoKPj4+IC0gICAgICogSWYgdGhlIHdyaXRlciBmaWVsZCBp cyBhdG9taWMsIGl0IGNhbiBiZSBjbGVhcmVkIGRpcmVjdGx5Lgo+Pj4gLSAgICAgKiBPdGhlcndp c2UsIGFuIGF0b21pYyBzdWJ0cmFjdGlvbiB3aWxsIGJlIHVzZWQgdG8gY2xlYXIgaXQuCj4+PiAt ICAgICAqLwo+Pj4gLSAgICBhdG9taWNfc3ViKF9RV19MT0NLRUQsICZsb2NrLT5jbnRzKTsKPj4+ ICsgICAgLyogU2luY2UgdGhlIHdyaXRlciBmaWVsZCBpcyBhdG9taWMsIGl0IGNhbiBiZSBjbGVh cmVkIGRpcmVjdGx5LiAqLwo+Pj4gKyAgICBBU1NFUlQoX2lzX3dyaXRlX2xvY2tlZF9ieV9tZShh dG9taWNfcmVhZCgmbG9jay0+Y250cykpKTsKPj4+ICsgICAgQlVJTERfQlVHX09OKF9RUl9TSElG VCAhPSAxNik7Cj4+PiArICAgIHdyaXRlX2F0b21pYygodWludDE2X3QgKikmbG9jay0+Y250cywg MCk7Cj4+Cj4+IEkgdGhpbmsgdGhpcyBpcyBhbiBhYnVzZSB0byBjYXN0IGFuIGF0b21pY190KCkg ZGlyZWN0bHkgaW50byBhIHVpbnQxNl90LiBZb3UKPj4gd291bGQgYXQgbGVhc3Qgd2FudCB0byB1 c2UgJmxvY2stPmNudHMuY291bnRlciBoZXJlLgo+IAo+IFN1cmUsIEkgd2FzIHdvbmRlcmluZyBh Ym91dCB0aGlzIG15c2VsZi4KPiAKPiBXaWxsIHdhaXQgZm9yIG1vcmUgY29tbWVudHMsIG5vdCBz dXJlIHdoZXRoZXIgdGhpcyBjYW4gYmUgZml4ZWQgdXBvbgo+IGNvbW1pdCBpZiB0aGVyZSBhcmUg bm8gb3RoZXIgaXNzdWVzLgoKSXQncyBtb3JlIHRoYW4ganVzdCBhZGRpbmcgYW5vdGhlciBmaWVs ZCBzcGVjaWZpZXIgaGVyZS4gQSBjYXN0IGxpa2UKdGhpcyBvbmUgaXMgZW5kaWFubmVzcy11bnNh ZmUsIGFuZCBoZW5jZSBhIHRyYXAgd2FpdGluZyBmb3IgYSBiaWcKZW5kaWFuIHBvcnQgYXR0ZW1w dCB0byBmYWxsIGludG8uIEF0IHRoZSB2ZXJ5IGxlYXN0IHRoaXMgc2hvdWxkIGNhdXNlCmEgYnVp bGQgZmFpbHVyZSBvbiBiaWcgZW5kaWFuIHN5c3RlbXMsIGV2ZW4gYmV0dGVyIHdvdWxkIGJlIGlm IGl0IHdhcwplbmRpYW5uZXNzLXNhZmUuCgpKYW4KCl9fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fClhlbi1kZXZlbCBtYWlsaW5nIGxpc3QKWGVuLWRldmVsQGxp c3RzLnhlbnByb2plY3Qub3JnCmh0dHBzOi8vbGlzdHMueGVucHJvamVjdC5vcmcvbWFpbG1hbi9s aXN0aW5mby94ZW4tZGV2ZWw=