From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Woodhouse Subject: Re: [PATCH RFC] solos-pci: Fix BUG() with shared skb Date: Wed, 04 Sep 2013 21:41:15 +0100 Message-ID: <1378327275.2627.28.camel@shinybook.infradead.org> References: <1378223125.4210.11.camel@i7.infradead.org> <20130904.143056.1558570610941220565.davem@davemloft.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="sha-1"; protocol="application/x-pkcs7-signature"; boundary="=-UFKuw1mvdtNR4rPnyCOx" Cc: netdev@vger.kernel.org, simon@fire.lp0.eu, linux-atm-general@lists.sourceforge.net, nathan@traverse.com.au To: David Miller Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:43579 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760051Ab3IDUlW (ORCPT ); Wed, 4 Sep 2013 16:41:22 -0400 In-Reply-To: <20130904.143056.1558570610941220565.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: --=-UFKuw1mvdtNR4rPnyCOx Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2013-09-04 at 14:30 -0400, David Miller wrote: > skb_realloc_headroom() should do everything you need. Great, thanks! Something like this then... ?=20 Do I really need the truesize check? And if so, is there a better way to handle the ATM accounting? It just *happens* to be the case that the the br2684_pop() and pppoatm_pop() functions don't mind being bypassed in this fashion, and we should probably get away with tweaking the core ATM accounting directly like this. Doesn't make me happy though... diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c index 32784d1..4492c0f 100644 --- a/drivers/atm/solos-pci.c +++ b/drivers/atm/solos-pci.c @@ -1145,19 +1145,19 @@ static int psend(struct atm_vcc *vcc, struct sk_buf= f *skb) return 0; } =20 - if (!skb_clone_writable(skb, sizeof(*header))) { - int expand_by =3D 0; - int ret; - - if (skb_headroom(skb) < sizeof(*header)) - expand_by =3D sizeof(*header) - skb_headroom(skb); - - ret =3D pskb_expand_head(skb, expand_by, 0, GFP_ATOMIC); - if (ret) { - dev_warn(&card->dev->dev, "pskb_expand_head failed.\n"); - solos_pop(vcc, skb); - return ret; - } + if (skb_headroom(skb) < sizeof(*header)) { + struct sk_buff *nskb; + + nskb =3D skb_realloc_headroom(skb, sizeof(*header)); + if (!nskb) { + solos_pop(vcc, skb); + return -ENOMEM; + } + if (skb->truesize !=3D nskb->truesize) + atm_force_charge(vcc, nskb->truesize - skb->truesize); +=20 + dev_kfree_skb_any(skb); + skb =3D nskb; } =20 header =3D (void *)skb_push(skb, sizeof(*header)); --=20 dwmw2 --=-UFKuw1mvdtNR4rPnyCOx Content-Type: application/x-pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIISxDCCBjQw ggQcoAMCAQICAR4wDQYJKoZIhvcNAQEFBQAwfTELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0 Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxKTAn BgNVBAMTIFN0YXJ0Q29tIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MB4XDTA3MTAyNDIxMDE1NVoX DTE3MTAyNDIxMDE1NVowgYwxCzAJBgNVBAYTAklMMRYwFAYDVQQKEw1TdGFydENvbSBMdGQuMSsw KQYDVQQLEyJTZWN1cmUgRGlnaXRhbCBDZXJ0aWZpY2F0ZSBTaWduaW5nMTgwNgYDVQQDEy9TdGFy dENvbSBDbGFzcyAxIFByaW1hcnkgSW50ZXJtZWRpYXRlIENsaWVudCBDQTCCASIwDQYJKoZIhvcN AQEBBQADggEPADCCAQoCggEBAMcJg8zOLdgasSmkLhOrlr6KMoOMpohBllVHrdRvEg/q6r8jR+EK 75xCGhR8ToREoqe7zM9/UnC6TS2y9UKTpT1v7RSMzR0t6ndl0TWBuUr/UXBhPk+Kmy7bI4yW4urC +y7P3/1/X7U8ocb8VpH/Clt+4iq7nirMcNh6qJR+xjOhV+VHzQMALuGYn5KZmc1NbJQYclsGkDxD z2UbFqE2+6vIZoL+jb9x4Pa5gNf1TwSDkOkikZB1xtB4ZqtXThaABSONdfmv/Z1pua3FYxnCFmdr /+N2JLKutIxMYqQOJebr/f/h5t95m4JgrM3Y/w7YX9d7YAL9jvN4SydHsU6n65cCAwEAAaOCAa0w ggGpMA8GA1UdEwEB/wQFMAMBAf8wDgYDVR0PAQH/BAQDAgEGMB0GA1UdDgQWBBRTcu2SnODaywFc fH6WNU7y1LhRgjAfBgNVHSMEGDAWgBROC+8apEBbpRdphzDKNGhD0EGu8jBmBggrBgEFBQcBAQRa MFgwJwYIKwYBBQUHMAGGG2h0dHA6Ly9vY3NwLnN0YXJ0c3NsLmNvbS9jYTAtBggrBgEFBQcwAoYh aHR0cDovL3d3dy5zdGFydHNzbC5jb20vc2ZzY2EuY3J0MFsGA1UdHwRUMFIwJ6AloCOGIWh0dHA6 Ly93d3cuc3RhcnRzc2wuY29tL3Nmc2NhLmNybDAnoCWgI4YhaHR0cDovL2NybC5zdGFydHNzbC5j b20vc2ZzY2EuY3JsMIGABgNVHSAEeTB3MHUGCysGAQQBgbU3AQIBMGYwLgYIKwYBBQUHAgEWImh0 dHA6Ly93d3cuc3RhcnRzc2wuY29tL3BvbGljeS5wZGYwNAYIKwYBBQUHAgEWKGh0dHA6Ly93d3cu c3RhcnRzc2wuY29tL2ludGVybWVkaWF0ZS5wZGYwDQYJKoZIhvcNAQEFBQADggIBAAqDCH14qywG XLhjjF6uHLkjd02hcdh9hrw+VUsv+q1eeQWB21jWj3kJ96AUlPCoEGZ/ynJNScWy6QMVQjbbMXlt UfO4n4bGGdKo3awPWp61tjAFgraLJgDk+DsSvUD6EowjMTNx25GQgyYJ5RPIzKKR9tQW8gGK+2+R HxkUCTbYFnL6kl8Ch507rUdPPipJ9CgJFws3kDS3gOS5WFMxcjO5DwKfKSETEPrHh7p5shuuNktv sv6hxHTLhiMKX893gxdT3XLS9OKmCv87vkINQcNEcIIoFWbP9HORz9v3vQwR4e3ksLc2JZOAFK+s sS5XMEoznzpihEP0PLc4dCBYjbvSD7kxgDwZ+Aj8Q9PkbvE9sIPP7ON0fz095HdThKjiVJe6vofq +n6b1NBc8XdrQvBmunwxD5nvtTW4vtN6VY7mUCmxsCieuoBJ9OlqmsVWQvifIYf40dJPZkk9YgGT zWLpXDSfLSplbY2LL9C9U0ptvjcDjefLTvqSFc7tw1sEhF0n/qpA2r0GpvkLRDmcSwVyPvmjFBGq Up/pNy8ZuPGQmHwFi2/14+xeSUDG2bwnsYJQG2EdJCB6luQ57GEnTA/yKZSTKI8dDQa8Sd3zfXb1 9mOgSF0bBdXbuKhEpuP9wirslFe6fQ1t5j5R0xi72MZ8ikMu1RQZKCyDbMwazlHiMIIGQjCCBSqg AwIBAgIDBoXOMA0GCSqGSIb3DQEBBQUAMIGMMQswCQYDVQQGEwJJTDEWMBQGA1UEChMNU3RhcnRD b20gTHRkLjErMCkGA1UECxMiU2VjdXJlIERpZ2l0YWwgQ2VydGlmaWNhdGUgU2lnbmluZzE4MDYG A1UEAxMvU3RhcnRDb20gQ2xhc3MgMSBQcmltYXJ5IEludGVybWVkaWF0ZSBDbGllbnQgQ0EwHhcN MTMwNTAyMDYyMDQ2WhcNMTQwNTAzMTIxNDAyWjBdMRkwFwYDVQQNExBNd0k3ODIxNTRpV21lZVkw MRwwGgYDVQQDDBNkd213MkBpbmZyYWRlYWQub3JnMSIwIAYJKoZIhvcNAQkBFhNkd213MkBpbmZy YWRlYWQub3JnMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvWGuRDHiXVpOgaFkBaz8 c3jQTfiEw7j0iKZnktCQi0xjY29QJ7GwL+fgQlbofXgYTm8E9fWERvw2tAy2BxHzAPguBzziS7JN hsGP9lf3L8hFJBvmdyyyj8b9A6Oi7s3JLtMRWIvyvE+DbuTkP+htuT4+XuTJr8Y5yIqd1WXr2gJk ANr77vTyjeNxceevP58Tqr0f+4v5g6+vNARO3bk3SaVQPDUTwGrpoPtLh3d+mQzZ4iiW3MwQS7Wr UVT3l2aTVHCpgtAaBs3zHWarvmIqhbWj8zdcnELNzwqTrOjaoWxuWY4k05GGfzmdjOBUiL7FDNvI ZwweJEPwJAQI72YhUwIDAQABo4IC2TCCAtUwCQYDVR0TBAIwADALBgNVHQ8EBAMCBLAwHQYDVR0l BBYwFAYIKwYBBQUHAwIGCCsGAQUFBwMEMB0GA1UdDgQWBBSs0hZhUgQwqGVXzLuH6pJH0hMZwTAf BgNVHSMEGDAWgBRTcu2SnODaywFcfH6WNU7y1LhRgjAeBgNVHREEFzAVgRNkd213MkBpbmZyYWRl YWQub3JnMIIBTAYDVR0gBIIBQzCCAT8wggE7BgsrBgEEAYG1NwECAzCCASowLgYIKwYBBQUHAgEW Imh0dHA6Ly93d3cuc3RhcnRzc2wuY29tL3BvbGljeS5wZGYwgfcGCCsGAQUFBwICMIHqMCcWIFN0 YXJ0Q29tIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MAMCAQEagb5UaGlzIGNlcnRpZmljYXRlIHdh cyBpc3N1ZWQgYWNjb3JkaW5nIHRvIHRoZSBDbGFzcyAxIFZhbGlkYXRpb24gcmVxdWlyZW1lbnRz IG9mIHRoZSBTdGFydENvbSBDQSBwb2xpY3ksIHJlbGlhbmNlIG9ubHkgZm9yIHRoZSBpbnRlbmRl ZCBwdXJwb3NlIGluIGNvbXBsaWFuY2Ugb2YgdGhlIHJlbHlpbmcgcGFydHkgb2JsaWdhdGlvbnMu MDYGA1UdHwQvMC0wK6ApoCeGJWh0dHA6Ly9jcmwuc3RhcnRzc2wuY29tL2NydHUxLWNybC5jcmww gY4GCCsGAQUFBwEBBIGBMH8wOQYIKwYBBQUHMAGGLWh0dHA6Ly9vY3NwLnN0YXJ0c3NsLmNvbS9z dWIvY2xhc3MxL2NsaWVudC9jYTBCBggrBgEFBQcwAoY2aHR0cDovL2FpYS5zdGFydHNzbC5jb20v Y2VydHMvc3ViLmNsYXNzMS5jbGllbnQuY2EuY3J0MCMGA1UdEgQcMBqGGGh0dHA6Ly93d3cuc3Rh cnRzc2wuY29tLzANBgkqhkiG9w0BAQUFAAOCAQEACFLDQnyO8+XA/TiTltjJ/ZAvM+qmBEKN43Vd +Wio2lM/Wq/scJpkupXGHrl9CueobkDxMAogXbMxqLZYO13PvgjMh+PHxDPnQv8EGxOig+k/Hqvc qEdTlm9YEHcbXbWS6XB+zRO7VVIpGMYQ1f1qCOcukxmwIm6iMSHXbOr/7paQm4bO0ULptjBotfiO Zo6q8No6SroQlOSyc6v8FYSxTNIAXMaM2FYkjqrxgdnJmSIAfr11gROuF69WuOICxP0zTEjJle+7 aO9lUWNaWMWPMyFSNCxF6kkRuvUCami7vlhLOTRC1kb+OMhx7keN9At3tdTI3rtuFeSB1Pa3VXVs 0DCCBkIwggUqoAMCAQICAwaFzjANBgkqhkiG9w0BAQUFADCBjDELMAkGA1UEBhMCSUwxFjAUBgNV BAoTDVN0YXJ0Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNp Z25pbmcxODA2BgNVBAMTL1N0YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xp ZW50IENBMB4XDTEzMDUwMjA2MjA0NloXDTE0MDUwMzEyMTQwMlowXTEZMBcGA1UEDRMQTXdJNzgy MTU0aVdtZWVZMDEcMBoGA1UEAwwTZHdtdzJAaW5mcmFkZWFkLm9yZzEiMCAGCSqGSIb3DQEJARYT ZHdtdzJAaW5mcmFkZWFkLm9yZzCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAL1hrkQx 4l1aToGhZAWs/HN40E34hMO49IimZ5LQkItMY2NvUCexsC/n4EJW6H14GE5vBPX1hEb8NrQMtgcR 8wD4Lgc84kuyTYbBj/ZX9y/IRSQb5ncsso/G/QOjou7NyS7TEViL8rxPg27k5D/obbk+Pl7kya/G OciKndVl69oCZADa++708o3jcXHnrz+fE6q9H/uL+YOvrzQETt25N0mlUDw1E8Bq6aD7S4d3fpkM 2eIoltzMEEu1q1FU95dmk1RwqYLQGgbN8x1mq75iKoW1o/M3XJxCzc8Kk6zo2qFsblmOJNORhn85 nYzgVIi+xQzbyGcMHiRD8CQECO9mIVMCAwEAAaOCAtkwggLVMAkGA1UdEwQCMAAwCwYDVR0PBAQD AgSwMB0GA1UdJQQWMBQGCCsGAQUFBwMCBggrBgEFBQcDBDAdBgNVHQ4EFgQUrNIWYVIEMKhlV8y7 h+qSR9ITGcEwHwYDVR0jBBgwFoAUU3Ltkpzg2ssBXHx+ljVO8tS4UYIwHgYDVR0RBBcwFYETZHdt dzJAaW5mcmFkZWFkLm9yZzCCAUwGA1UdIASCAUMwggE/MIIBOwYLKwYBBAGBtTcBAgMwggEqMC4G CCsGAQUFBwIBFiJodHRwOi8vd3d3LnN0YXJ0c3NsLmNvbS9wb2xpY3kucGRmMIH3BggrBgEFBQcC AjCB6jAnFiBTdGFydENvbSBDZXJ0aWZpY2F0aW9uIEF1dGhvcml0eTADAgEBGoG+VGhpcyBjZXJ0 aWZpY2F0ZSB3YXMgaXNzdWVkIGFjY29yZGluZyB0byB0aGUgQ2xhc3MgMSBWYWxpZGF0aW9uIHJl cXVpcmVtZW50cyBvZiB0aGUgU3RhcnRDb20gQ0EgcG9saWN5LCByZWxpYW5jZSBvbmx5IGZvciB0 aGUgaW50ZW5kZWQgcHVycG9zZSBpbiBjb21wbGlhbmNlIG9mIHRoZSByZWx5aW5nIHBhcnR5IG9i bGlnYXRpb25zLjA2BgNVHR8ELzAtMCugKaAnhiVodHRwOi8vY3JsLnN0YXJ0c3NsLmNvbS9jcnR1 MS1jcmwuY3JsMIGOBggrBgEFBQcBAQSBgTB/MDkGCCsGAQUFBzABhi1odHRwOi8vb2NzcC5zdGFy dHNzbC5jb20vc3ViL2NsYXNzMS9jbGllbnQvY2EwQgYIKwYBBQUHMAKGNmh0dHA6Ly9haWEuc3Rh cnRzc2wuY29tL2NlcnRzL3N1Yi5jbGFzczEuY2xpZW50LmNhLmNydDAjBgNVHRIEHDAahhhodHRw Oi8vd3d3LnN0YXJ0c3NsLmNvbS8wDQYJKoZIhvcNAQEFBQADggEBAAhSw0J8jvPlwP04k5bYyf2Q LzPqpgRCjeN1XfloqNpTP1qv7HCaZLqVxh65fQrnqG5A8TAKIF2zMai2WDtdz74IzIfjx8Qz50L/ BBsTooPpPx6r3KhHU5ZvWBB3G121kulwfs0Tu1VSKRjGENX9agjnLpMZsCJuojEh12zq/+6WkJuG ztFC6bYwaLX4jmaOqvDaOkq6EJTksnOr/BWEsUzSAFzGjNhWJI6q8YHZyZkiAH69dYETrhevVrji AsT9M0xIyZXvu2jvZVFjWljFjzMhUjQsRepJEbr1Ampou75YSzk0QtZG/jjIce5HjfQLd7XUyN67 bhXkgdT2t1V1bNAxggNvMIIDawIBATCBlDCBjDELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0 Q29tIEx0ZC4xKzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxODA2 BgNVBAMTL1N0YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xpZW50IENBAgMG hc4wCQYFKw4DAhoFAKCCAa8wGAYJKoZIhvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUx DxcNMTMwOTA0MjA0MTE1WjAjBgkqhkiG9w0BCQQxFgQU9tItWzO23qbZ9F67LmEhSvr6oYswgaUG CSsGAQQBgjcQBDGBlzCBlDCBjDELMAkGA1UEBhMCSUwxFjAUBgNVBAoTDVN0YXJ0Q29tIEx0ZC4x KzApBgNVBAsTIlNlY3VyZSBEaWdpdGFsIENlcnRpZmljYXRlIFNpZ25pbmcxODA2BgNVBAMTL1N0 YXJ0Q29tIENsYXNzIDEgUHJpbWFyeSBJbnRlcm1lZGlhdGUgQ2xpZW50IENBAgMGhc4wgacGCyqG SIb3DQEJEAILMYGXoIGUMIGMMQswCQYDVQQGEwJJTDEWMBQGA1UEChMNU3RhcnRDb20gTHRkLjEr MCkGA1UECxMiU2VjdXJlIERpZ2l0YWwgQ2VydGlmaWNhdGUgU2lnbmluZzE4MDYGA1UEAxMvU3Rh cnRDb20gQ2xhc3MgMSBQcmltYXJ5IEludGVybWVkaWF0ZSBDbGllbnQgQ0ECAwaFzjANBgkqhkiG 9w0BAQEFAASCAQCnA01wQaI7BCUNBan2E3wX8PXEV+8oPgtNqWGITP6KiXBkldA253Oe2rsA7CW/ +2znYi2tz9Ji4375thgKQJnIr5QB/c+k3j9y9i8LnTQ1DxyNmNKTJSkMtGJ3N6rImFq9oNNDbUjd 1uXiyaYz5I7CLNWFpO+sLJvLV783pG+OsksueCcx22Eo8tUPPis8jNm/c2lf/BpENadC2BmuuTs8 zn0Zad2CIJ1OaEvPmNOcWBIRX8P/vVH/N+fl/U/NBahYNBUq9AopmVRA4QkM4Ja+WogWambIiEzj ZQw7TXsPnCxmHXQbWWVsmA2EqXzpnu6Lzl7MFvgOxsASDI3BqSzEAAAAAAAA --=-UFKuw1mvdtNR4rPnyCOx--