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=-8.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 251EEC5517A for ; Tue, 20 Oct 2020 21:56:23 +0000 (UTC) Received: from mail02.groups.io (mail02.groups.io [66.175.222.108]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 218F42237B for ; Tue, 20 Oct 2020 21:56:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=lists.cip-project.org header.i=@lists.cip-project.org header.b="L2rnhxSo" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 218F42237B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bp.renesas.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=bounce+64572+5628+4520388+8129055@lists.cip-project.org X-Received: by 127.0.0.2 with SMTP id hUBSYY4521723xpQcfxCDTXW; Tue, 20 Oct 2020 14:56:21 -0700 X-Received: from JPN01-OS2-obe.outbound.protection.outlook.com (JPN01-OS2-obe.outbound.protection.outlook.com [40.107.141.101]) by mx.groups.io with SMTP id smtpd.web12.2400.1603230980159439433 for ; Tue, 20 Oct 2020 14:56:20 -0700 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=PREsgdJkKfq8YkBc+4E1IC5EiI6P3ytHxM56Ln/LzzRWKjPUtlzyksONuPRdiiMZKhCaiPMsFm2xB1fOemyRiVOHnAQ42ClEFJ4OWluow29GYTHyKYOFtHgzadlKddFHGTZC/qi7uyphp9iwMj+XZWeqqvWIbAEUp3SUqHUhxvGuyuoREwcfZ1VjNOAwXt7Et1QIW/Q0Bl8YMHU7Yyyy9fBgOyRqE+ojnH2ZgvbrWYZx4ZWHCTAnorXJ2DnsP3fQT1SOCyMj+Zhg0+I5scpvSPQqmSQBas/J0tObtJqj7meVJ3Iho4q9YIJBIgxoSe5KnUYQitWirsggZzTqCR2oPA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=DcX1RA3YKWEACMaJrj6D2REiRk/y0B1P5atUeWXKUmM=; b=ju3Oo+t+x5UD2PyJVBxmJA4uBW+vf6jUgGORvcnSSGIUxuTsf+UUE6HMG4yyJtqESCy/wg7Dm71ZVgSvNLlcQQhenaQjUSBiugEBnhFY/Inf8Ws9B/wVvxnCYc2BYSn0jO+AR+UHR7qy1g2S8z23vAj27e+5TJDa8pMJOaH8mAZ04CLPAQtoGTXwpdqO40uBaFmIloFNROVJ0ruoY7nvbkv69I0TimU9Sb25GSEoQjCz6xh0sEa/FOCnPVBuUTd8IS3A23qeR+EJJRWbnL9ougfbmf27enM1MS4gnjMpik0Yq5WHsiuqJUM5Ap7amqDPgKFAWoEf8qGhPS7TGU+2pQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=bp.renesas.com; dmarc=pass action=none header.from=bp.renesas.com; dkim=pass header.d=bp.renesas.com; arc=none X-Received: from OSBPR01MB5048.jpnprd01.prod.outlook.com (2603:1096:604:38::10) by OSYPR01MB5445.jpnprd01.prod.outlook.com (2603:1096:604:84::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3499.18; Tue, 20 Oct 2020 21:56:14 +0000 X-Received: from OSBPR01MB5048.jpnprd01.prod.outlook.com ([fe80::18f:c7ea:e9e4:db70]) by OSBPR01MB5048.jpnprd01.prod.outlook.com ([fe80::18f:c7ea:e9e4:db70%3]) with mapi id 15.20.3477.028; Tue, 20 Oct 2020 21:56:14 +0000 From: "Lad Prabhakar" To: Pavel Machek CC: "cip-dev@lists.cip-project.org" , Nobuhiro Iwamatsu , Biju Das Subject: Re: [cip-dev] [RFC PATCH 4.19.y-cip 24/50] PCI: endpoint: Replace spinlock with mutex Thread-Topic: [RFC PATCH 4.19.y-cip 24/50] PCI: endpoint: Replace spinlock with mutex Thread-Index: AQHWoKLMcmEZW4H6iEuZ4dh3fP82qqmhAhSAgAAOJ+A= Date: Tue, 20 Oct 2020 21:56:14 +0000 Message-ID: References: <20201012141933.9652-1-prabhakar.mahadev-lad.rj@bp.renesas.com> <20201012141933.9652-25-prabhakar.mahadev-lad.rj@bp.renesas.com> <20201020204332.GB29993@duo.ucw.cz> In-Reply-To: <20201020204332.GB29993@duo.ucw.cz> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [193.141.220.21] x-ms-publictraffictype: Email x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: cdfb768b-ad70-47dd-9594-08d87542f710 x-ms-traffictypediagnostic: OSYPR01MB5445: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:9508; x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: tIOoJKFV6pGwSXxdQ9le2yxJ73Z9dSQv21bZ6E3v3wLXX7E2EA/gQmSYyowgtDxZbe7Z9az+JlfS7+oBZhOVp6DKijK6jmq5fYA2brYzxtYGTW9jBOQ9Uwd6MK/1C1kZvCe074BwEzORO1Dheinu6rQl0lW0vmEaaUeJ4D3OEAm0+BIm4dJXMaiV1tJEkuQpmH7gBQh1F88ZZpklZkm0Hg6suyoeulbb/6Tr94Nr1btiWdVr1g8HUbRGSU/8mSYRUjNpcutoLQaSRNh314BnYk60ENGNgw+0FaQl9QUqpyDaPtQCM8E8vXwxu9jM33DP0Dk/VQGGShHdXUs8n14JAPX8L8lBslizVIKBNqCzBhbPHIrDwlf5QAngj6F9EgMD55CLco02jb8N802Cdx3t4w== x-ms-exchange-antispam-messagedata: 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 MIME-Version: 1.0 X-OriginatorOrg: bp.renesas.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: OSBPR01MB5048.jpnprd01.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: cdfb768b-ad70-47dd-9594-08d87542f710 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Oct 2020 21:56:14.4356 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 53d82571-da19-47e4-9cb4-625a166a4a2a X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 8TyNJvM9vJ5C6hiWiAUtJZJ6nvLJ5+HlQ//gx0UnjUL3dZUn7opw2mle14fhP+uZN56xQn+dq/3lSv9CZZNNyMu13aOW5Sg9s44CzHrsOqeXFQYRrsjJJz7d2I8OLTX1 X-MS-Exchange-Transport-CrossTenantHeadersStamped: OSYPR01MB5445 Precedence: Bulk List-Unsubscribe: Sender: cip-dev@lists.cip-project.org List-Id: Mailing-List: list cip-dev@lists.cip-project.org; contact cip-dev+owner@lists.cip-project.org Reply-To: cip-dev@lists.cip-project.org X-Gm-Message-State: Mwpdzn9qw4QDKRgEuR9Q47Zcx4520388AA= Content-Type: multipart/mixed; boundary="1rkq5HyFzVS73KrWHncb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.cip-project.org; q=dns/txt; s=20140610; t=1603230981; bh=z9+QZnogo5LN6nnFMhjiGwNV55NVFP0QFlUquphxtOE=; h=CC:Content-Type:Date:From:Reply-To:Subject:To; b=L2rnhxSoSHt+YGguuJEoSD/CZEIwfv2ypruD1ZlrDqGyYGdDNhFM6aAFOfK0YcwDbrT ZsqdFRdNMvXtxkAr6rdi7BHqPrXRrX/NrVhy1TfgftaQgrGRBQfDjj4dcbUsv7eaj0aF0 Q9bkGcQ35RDuA62mw+T/gY2buFlB835n/Mo= --1rkq5HyFzVS73KrWHncb Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Pavel, > -----Original Message----- > From: Pavel Machek > Sent: 20 October 2020 21:44 > To: Prabhakar Mahadev Lad > Cc: cip-dev@lists.cip-project.org; Nobuhiro Iwamatsu ; Pavel Machek ; Biju Das > > Subject: Re: [RFC PATCH 4.19.y-cip 24/50] PCI: endpoint: Replace spinlock= with mutex >=20 > Hi! >=20 > > commit 3d3248dbd018502f654064c78efcd2e165ab3486 upstream. > > > > The pci_epc_ops is not intended to be invoked from interrupt context. > > Hence replace spin_lock_irqsave and spin_unlock_irqrestore with > > mutex_lock and mutex_unlock respectively. >=20 > Could I get some kind of explanation why this is good idea? >=20 Apart of one mentioned above other point I would add is on a single core ma= chine mutex_lock/unlock would be good choice. Also to add the callbacks in controller driver might sleep. For example in = raise_irq callback [1], [2]. > As long as code protected by the locks does not sleep, spinlocks are > okay... (but they should not need "_irqsave" variants). >=20 > They are likely to have better performance, too, when protected code > is small and fast. >=20 I do agree with the above two points *if the code isn't sleeping*. [1] https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/tree/= drivers/pci/controller/pcie-rockchip-ep.c?h=3Dlinux-4.19.y-cip#n410 [2] https://git.kernel.org/pub/scm/linux/kernel/git/cip/linux-cip.git/tree/= drivers/pci/controller/pcie-cadence-ep.c?h=3Dlinux-4.19.y-cip#n310 Cheers, Prabhakar > Best regards, > Pavel > -- > DENX Software Engineering GmbH, Managing Director: Wolfgang Denk > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany --1rkq5HyFzVS73KrWHncb Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- Links: You receive all messages sent to this group. View/Reply Online (#5628): https://lists.cip-project.org/g/cip-dev/message= /5628 Mute This Topic: https://lists.cip-project.org/mt/77461695/4520388 Group Owner: cip-dev+owner@lists.cip-project.org Unsubscribe: https://lists.cip-project.org/g/cip-dev/leave/8129055/7279483= 98/xyzzy [cip-dev@archiver.kernel.org] -=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D- --1rkq5HyFzVS73KrWHncb--