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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3AC51C32771 for ; Tue, 27 Sep 2022 01:26:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229639AbiI0B0B (ORCPT ); Mon, 26 Sep 2022 21:26:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbiI0BZ7 (ORCPT ); Mon, 26 Sep 2022 21:25:59 -0400 Received: from unicom146.biz-email.net (unicom146.biz-email.net [210.51.26.146]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E765963F07; Mon, 26 Sep 2022 18:25:56 -0700 (PDT) Received: from ([60.208.111.195]) by unicom146.biz-email.net ((D)) with ASMTP (SSL) id VAA00051; Tue, 27 Sep 2022 09:25:51 +0800 Received: from jtjnmail201619.home.langchao.com (10.100.2.19) by jtjnmail201622.home.langchao.com (10.100.2.22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.12; Tue, 27 Sep 2022 09:25:51 +0800 Received: from jtjnmail201619.home.langchao.com ([fe80::c426:eceb:41d0:3372]) by jtjnmail201619.home.langchao.com ([fe80::c426:eceb:41d0:3372%2]) with mapi id 15.01.2507.012; Tue, 27 Sep 2022 09:25:51 +0800 From: =?gb2312?B?dG9tb3Jyb3cgV2FuZyAozfW1wsP3KQ==?= To: "viro@zeniv.linux.org.uk" , "jgg@nvidia.com" CC: "pbonzini@redhat.com" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] vfio: Use filp instead of fd Thread-Topic: [PATCH] vfio: Use filp instead of fd Thread-Index: AdjSD382bkUUuQYWTu6MpzuiJRbcew== Date: Tue, 27 Sep 2022 01:25:51 +0000 Message-ID: <0a80a16aa10142c5811eb6151f7cdbc9@inspur.com> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: yes X-MS-TNEF-Correlator: x-originating-ip: [10.200.104.82] Content-Type: multipart/signed; protocol="application/x-pkcs7-signature"; micalg=SHA1; boundary="----=_NextPart_000_000F_01D8D253.0843A8C0" MIME-Version: 1.0 tUid: 20229270925510745c261ed230e182cf321e4f577c8ab X-Abuse-Reports-To: service@corp-email.com Abuse-Reports-To: service@corp-email.com X-Complaints-To: service@corp-email.com X-Report-Abuse-To: service@corp-email.com Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org ------=_NextPart_000_000F_01D8D253.0843A8C0 Content-Type: text/plain; charset="gb2312" Content-Transfer-Encoding: quoted-printable Hi, Why kvm_vfio_group_add use file?=20 struct file *filp; ...... filp =3D fget(fd); ...... fput(filp); >-------- > send: Al Viro =B4=FA=B1=ED Al Viro > =B7=A2=CB=CD=CA=B1=BC=E4: 2022=C4=EA9=D4=C227=C8=D5 3:38 >to: Jason Gunthorpe > pbonzini@redhat.com; kvm@vger.kernel.org; linux-kernel@vger.kernel.org > sub: Re: [PATCH] vfio: Use filp instead of fd >=20 > On Mon, Sep 26, 2022 at 02:07:43PM -0300, Jason Gunthorpe wrote: > > On Mon, Sep 26, 2022 at 02:54:07AM -0400, Deming Wang wrote: > > > The function of kvm_vfio_group_set_spapr_tce and = kvm_vfio_group_del > > > use fd indirectly.But,it only be used for fd.file. So,we can > > > directly use the struct of file instead. > > > > > > Signed-off-by: Deming Wang > > > --- > > > virt/kvm/vfio.c | 24 ++++++++++++------------ > > > 1 file changed, 12 insertions(+), 12 deletions(-) > > > > I thought about changing this too when I was looking at this. > > fdget/fdput includes a tiny micro-optimization that is legal here, > > however I doubt anyone cares about performance on this path. >=20 > Microoptimization or not, I'd rather keep fget() limited to cases = where we > really need it. There are non-trivial cases and having them easy to = find is a > good thing. >=20 > Again, the preferred way to do descriptor lookups is fdget() family, = not fget() > one. ------=_NextPart_000_000F_01D8D253.0843A8C0 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIK8zCCA6Iw ggKKoAMCAQICEGPKUixTOHaaTcIS5DrQVuowDQYJKoZIhvcNAQELBQAwWTETMBEGCgmSJomT8ixk ARkWA2NvbTEYMBYGCgmSJomT8ixkARkWCGxhbmdjaGFvMRQwEgYKCZImiZPyLGQBGRYEaG9tZTES MBAGA1UEAxMJSU5TUFVSLUNBMB4XDTE3MDEwOTA5MjgzMFoXDTI3MDEwOTA5MzgyOVowWTETMBEG CgmSJomT8ixkARkWA2NvbTEYMBYGCgmSJomT8ixkARkWCGxhbmdjaGFvMRQwEgYKCZImiZPyLGQB GRYEaG9tZTESMBAGA1UEAxMJSU5TUFVSLUNBMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKC AQEAq+Q17xtjJLyp5hgXDie1r4DeNj76VUvbZNSywWU5zhx+e0Lu0kwcZ0T3KncZdgdWyqYvRJMQ /VVqX3gS4VxtLw3zBrg9kGuD0LfpH0cA2b0ZHpxRh5WapP14flcSh/lnawig29z44wfUEg43yTZO lOfPKos/Dm6wyrJtaPmD6AF7w4+vFZH0zMYfjQkSN/xGgS3OPBNAB8PTHM2sV+fFmnnlTFpyRg0O IIA2foALZvjIjNdUfp8kMGSh/ZVMfHqTH4eo+FcZPZ+t9nTaJQz9cSylw36+Ig6FGZHA/Zq+0fYy VCxR1ZLULGS6wsVep8j075zlSinrVpMadguOcArThwIDAQABo2YwZDATBgkrBgEEAYI3FAIEBh4E AEMAQTALBgNVHQ8EBAMCAYYwDwYDVR0TAQH/BAUwAwEB/zAdBgNVHQ4EFgQUXlkDprRMWGCRTvYe taU5pjLBNWowEAYJKwYBBAGCNxUBBAMCAQAwDQYJKoZIhvcNAQELBQADggEBAErE37vtdSu2iYVX Fvmrg5Ce4Y5NyEyvaTh5rTGt/CeDjuFS5kwYpHVLt3UFYJxLPTlAuBKNBwJuQTDXpnEOkBjTwukC 0VZ402ag3bvF/AQ81FVycKZ6ts8cAzd2GOjRrQylYBwZb/H3iTfEsAf5rD/eYFBNS6a4cJ27OQ3s Y4N3ZyCXVRlogsH+dXV8Nn68BsHoY76TvgWbaxVsIeprTdSZUzNCscb5rx46q+fnE0FeHK01iiKA xliHryDoksuCJoHhKYxQTuS82A9r5EGALTdmRxhSLL/kvr2M3n3WZmVL6UulBFsNSKJXuIzTe2+D mMr5DYcsm0ZfNbDOAVrLPnUwggdJMIIGMaADAgECAhN+AADW2NzeiRillYrtAAAAANbYMA0GCSqG SIb3DQEBCwUAMFkxEzARBgoJkiaJk/IsZAEZFgNjb20xGDAWBgoJkiaJk/IsZAEZFghsYW5nY2hh bzEUMBIGCgmSJomT8ixkARkWBGhvbWUxEjAQBgNVBAMTCUlOU1BVUi1DQTAeFw0yMDA4MDYxMTEz MzdaFw0yNTA4MDUxMTEzMzdaMIGfMRMwEQYKCZImiZPyLGQBGRYDY29tMRgwFgYKCZImiZPyLGQB GRYIbGFuZ2NoYW8xFDASBgoJkiaJk/IsZAEZFgRob21lMR4wHAYDVQQLDBXkupHmlbDmja7kuK3l v4Ppm4blm6IxEjAQBgNVBAMMCeeOi+W+t+aYjjEkMCIGCSqGSIb3DQEJARYVd2FuZ2RlbWluZ0Bp bnNwdXIuY29tMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA2vlBZLJq8TGM+29yQN3P JA6nQmkd95s06bHPiYoLyRo1s8ow3GEo+AXrGTrvfAQSqDuM20xwoTdNxaxzHw73OT/a1WaBGZBG LSExU/PwnxpYNWy6VEkOEMgLzb790SRCsJ+tg9JDYzSoQYx2nxVI6qoR4lEOeQcwGkgO76IsJrEk L4/i9bgkH8SGGN8OCIG8OyKag4j12raDfKEV4B1g+RhQqPua6orrK30akBWSL0P1anheVOlWDrqy osJcF64HTzmDyqPLMzISF69XMhCfmxyaKSkLbFLmNE0eEZVJsdhGyV4e0qAx3kpqeTThtzOYMwkT oiUcyhkbr/tlBqNlwQIDAQABo4IDwTCCA70wPQYJKwYBBAGCNxUHBDAwLgYmKwYBBAGCNxUIgvKp H4SB13qGqZE9hoD3FYPYj1yBSv2LJoGUp00CAWQCAWAwKQYDVR0lBCIwIAYIKwYBBQUHAwIGCCsG AQUFBwMEBgorBgEEAYI3CgMEMAsGA1UdDwQEAwIFoDA1BgkrBgEEAYI3FQoEKDAmMAoGCCsGAQUF BwMCMAoGCCsGAQUFBwMEMAwGCisGAQQBgjcKAwQwRAYJKoZIhvcNAQkPBDcwNTAOBggqhkiG9w0D AgICAIAwDgYIKoZIhvcNAwQCAgCAMAcGBSsOAwIHMAoGCCqGSIb3DQMHMB0GA1UdDgQWBBT2m8+B pv3zOH+FCDvTbpfMkvPbAzAfBgNVHSMEGDAWgBReWQOmtExYYJFO9h61pTmmMsE1ajCCAQ8GA1Ud HwSCAQYwggECMIH/oIH8oIH5hoG6bGRhcDovLy9DTj1JTlNQVVItQ0EsQ049SlRDQTIwMTIsQ049 Q0RQLENOPVB1YmxpYyUyMEtleSUyMFNlcnZpY2VzLENOPVNlcnZpY2VzLENOPUNvbmZpZ3VyYXRp b24sREM9aG9tZSxEQz1sYW5nY2hhbyxEQz1jb20/Y2VydGlmaWNhdGVSZXZvY2F0aW9uTGlzdD9i YXNlP29iamVjdENsYXNzPWNSTERpc3RyaWJ1dGlvblBvaW50hjpodHRwOi8vSlRDQTIwMTIuaG9t ZS5sYW5nY2hhby5jb20vQ2VydEVucm9sbC9JTlNQVVItQ0EuY3JsMIIBKQYIKwYBBQUHAQEEggEb MIIBFzCBsQYIKwYBBQUHMAKGgaRsZGFwOi8vL0NOPUlOU1BVUi1DQSxDTj1BSUEsQ049UHVibGlj JTIwS2V5JTIwU2VydmljZXMsQ049U2VydmljZXMsQ049Q29uZmlndXJhdGlvbixEQz1ob21lLERD PWxhbmdjaGFvLERDPWNvbT9jQUNlcnRpZmljYXRlP2Jhc2U/b2JqZWN0Q2xhc3M9Y2VydGlmaWNh dGlvbkF1dGhvcml0eTBhBggrBgEFBQcwAoZVaHR0cDovL0pUQ0EyMDEyLmhvbWUubGFuZ2NoYW8u Y29tL0NlcnRFbnJvbGwvSlRDQTIwMTIuaG9tZS5sYW5nY2hhby5jb21fSU5TUFVSLUNBLmNydDBH BgNVHREEQDA+oCUGCisGAQQBgjcUAgOgFwwVd2FuZ2RlbWluZ0BpbnNwdXIuY29tgRV3YW5nZGVt aW5nQGluc3B1ci5jb20wDQYJKoZIhvcNAQELBQADggEBAKD6Oh0Yu1g2xXDIaczYlx8WZiYqTi7t bFCmsNT5DmNUfLaJre5UDyaWjgwW6Z/KN1X19Piy6oS8ex93gaeF4siDuQimREZoKxePJyUeyFs5 oC6kpsw95f/0RM5zhHb4I8L4AgplfwySCGAeMRr74rThzkYWfoU1AM+c8cBtViIispknx6KxJFo2 b533lCx168UKeNRb1n7pUANxFYd+1jjdRKCPrszdJcJddFmnLBetcnD4DG0ID62hnw+/g0KoAlfd ORikFVBLobsDNy+NQ++5ZYgx1ahEQ6BESIjeWxut+2Zqis6Zbwd5ZsBhm892l5EdzJCuYe5xDEZw 0Z0bGvUxggOTMIIDjwIBATBwMFkxEzARBgoJkiaJk/IsZAEZFgNjb20xGDAWBgoJkiaJk/IsZAEZ FghsYW5nY2hhbzEUMBIGCgmSJomT8ixkARkWBGhvbWUxEjAQBgNVBAMTCUlOU1BVUi1DQQITfgAA 1tjc3okYpZWK7QAAAADW2DAJBgUrDgMCGgUAoIIB+DAYBgkqhkiG9w0BCQMxCwYJKoZIhvcNAQcB MBwGCSqGSIb3DQEJBTEPFw0yMjA5MjcwMTI1MDdaMCMGCSqGSIb3DQEJBDEWBBTwjNsrSZpPKUh0 g8frdXbNy5KD1zB/BgkrBgEEAYI3EAQxcjBwMFkxEzARBgoJkiaJk/IsZAEZFgNjb20xGDAWBgoJ kiaJk/IsZAEZFghsYW5nY2hhbzEUMBIGCgmSJomT8ixkARkWBGhvbWUxEjAQBgNVBAMTCUlOU1BV Ui1DQQITfgAA1tjc3okYpZWK7QAAAADW2DCBgQYLKoZIhvcNAQkQAgsxcqBwMFkxEzARBgoJkiaJ k/IsZAEZFgNjb20xGDAWBgoJkiaJk/IsZAEZFghsYW5nY2hhbzEUMBIGCgmSJomT8ixkARkWBGhv bWUxEjAQBgNVBAMTCUlOU1BVUi1DQQITfgAA1tjc3okYpZWK7QAAAADW2DCBkwYJKoZIhvcNAQkP MYGFMIGCMAoGCCqGSIb3DQMHMAsGCWCGSAFlAwQBKjALBglghkgBZQMEARYwCwYJYIZIAWUDBAEC MA4GCCqGSIb3DQMCAgIAgDANBggqhkiG9w0DAgIBQDAHBgUrDgMCGjALBglghkgBZQMEAgMwCwYJ YIZIAWUDBAICMAsGCWCGSAFlAwQCATANBgkqhkiG9w0BAQEFAASCAQA9bA1oV93h2REQptZ9z952 Kh0R2Ka02hjW1V9LS/tT7egXmAyUrwIHcG4mSv9/adRPLaqj6QiYM/KPv/LZkuENqBJDPSIuMBF3 ODKEA/t750FJ1uwE+fXMuwT5gvbahI2nQZFVHpq5EybJIfqOzLkGH0DNmLmxgiiKz8eqEZE51+l8 PSaBOGYpv3TuSnHNxhN8rJXRH56lyatHJzzs7P6PffPgyFEazEUA4MxfuyYX/DitIkAcsFMRsKEb hroS5uCSNXAaJ92aZep2xtZ0svTbgJgKC06dsqcg1/GNQ5O6JyaBMOGIzutCW96rdHpNfry8pWn6 VgrfZgnMEiN5XrP2AAAAAAAA ------=_NextPart_000_000F_01D8D253.0843A8C0--