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Miller" , "open list:HIPPI" , netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org From: Colin Ian King Openpgp: preference=signencrypt Autocrypt: addr=colin.king@canonical.com; prefer-encrypt=mutual; keydata= mQINBE6TJCgBEACo6nMNvy06zNKj5tiwDsXXS+LhT+LwtEsy9EnraKYXAf2xwazcICSjX06e fanlyhB0figzQO0n/tP7BcfMVNG7n1+DC71mSyRK1ZERcG1523ajvdZOxbBCTvTitYOy3bjs +LXKqeVMhK3mRvdTjjmVpWnWqJ1LL+Hn12ysDVVfkbtuIm2NoaSEC8Ae8LSSyCMecd22d9Pn LR4UeFgrWEkQsqROq6ZDJT9pBLGe1ZS0pVGhkRyBP9GP65oPev39SmfAx9R92SYJygCy0pPv BMWKvEZS/7bpetPNx6l2xu9UvwoeEbpzUvH26PHO3DDAv0ynJugPCoxlGPVf3zcfGQxy3oty dNTWkP6Wh3Q85m+AlifgKZudjZLrO6c+fAw/jFu1UMjNuyhgShtFU7NvEzL3RqzFf9O1qM2m uj83IeFQ1FZ65QAiCdTa3npz1vHc7N4uEQBUxyXgXfCI+A5yDnjHwzU0Y3RYS52TA3nfa08y LGPLTf5wyAREkFYou20vh5vRvPASoXx6auVf1MuxokDShVhxLpryBnlKCobs4voxN54BUO7m zuERXN8kadsxGFzItAyfKYzEiJrpUB1yhm78AecDyiPlMjl99xXk0zs9lcKriaByVUv/NsyJ FQj/kmdxox3XHi9K29kopFszm1tFiDwCFr/xumbZcMY17Yi2bQARAQABtCVDb2xpbiBLaW5n IDxjb2xpbi5raW5nQGNhbm9uaWNhbC5jb20+iQI2BBMBCAAhBQJOkyQoAhsDBQsJCAcDBRUK CQgLBRYCAwEAAh4BAheAAAoJEGjCh9/GqAImsBcP9i6C/qLewfi7iVcOwqF9avfGzOPf7CVr n8CayQnlWQPchmGKk6W2qgnWI2YLIkADh53TS0VeSQ7Tetj8f1gV75eP0Sr/oT/9ovn38QZ2 vN8hpZp0GxOUrzkvvPjpH+zdmKSaUsHGp8idfPpZX7XeBO0yojAs669+3BrnBcU5wW45SjSV nfmVj1ZZj3/yBunb+hgNH1QRcm8ZPICpjvSsGFClTdB4xu2AR28eMiL/TTg9k8Gt72mOvhf0 fS0/BUwcP8qp1TdgOFyiYpI8CGyzbfwwuGANPSupGaqtIRVf+/KaOdYUM3dx/wFozZb93Kws gXR4z6tyvYCkEg3x0Xl9BoUUyn9Jp5e6FOph2t7TgUvv9dgQOsZ+V9jFJplMhN1HPhuSnkvP 5/PrX8hNOIYuT/o1AC7K5KXQmr6hkkxasjx16PnCPLpbCF5pFwcXc907eQ4+b/42k+7E3fDA Erm9blEPINtt2yG2UeqEkL+qoebjFJxY9d4r8PFbEUWMT+t3+dmhr/62NfZxrB0nTHxDVIia u8xM+23iDRsymnI1w0R78yaa0Eea3+f79QsoRW27Kvu191cU7QdW1eZm05wO8QUvdFagVVdW Zg2DE63Fiin1AkGpaeZG9Dw8HL3pJAJiDe0KOpuq9lndHoGHs3MSa3iyQqpQKzxM6sBXWGfk EkK5Ag0ETpMkKAEQAMX6HP5zSoXRHnwPCIzwz8+inMW7mJ60GmXSNTOCVoqExkopbuUCvinN 4Tg+AnhnBB3R1KTHreFGoz3rcV7fmJeut6CWnBnGBtsaW5Emmh6gZbO5SlcTpl7QDacgIUuT v1pgewVHCcrKiX0zQDJkcK8FeLUcB2PXuJd6sJg39kgsPlI7R0OJCXnvT/VGnd3XPSXXoO4K cr5fcjsZPxn0HdYCvooJGI/Qau+imPHCSPhnX3WY/9q5/WqlY9cQA8tUC+7mgzt2VMjFft1h rp/CVybW6htm+a1d4MS4cndORsWBEetnC6HnQYwuC4bVCOEg9eXMTv88FCzOHnMbE+PxxHzW 3Gzor/QYZGcis+EIiU6hNTwv4F6fFkXfW6611JwfDUQCAHoCxF3B13xr0BH5d2EcbNB6XyQb IGngwDvnTyKHQv34wE+4KtKxxyPBX36Z+xOzOttmiwiFWkFp4c2tQymHAV70dsZTBB5Lq06v 6nJs601Qd6InlpTc2mjd5mRZUZ48/Y7i+vyuNVDXFkwhYDXzFRotO9VJqtXv8iqMtvS4xPPo 2DtJx6qOyDE7gnfmk84IbyDLzlOZ3k0p7jorXEaw0bbPN9dDpw2Sh9TJAUZVssK119DJZXv5 2BSc6c+GtMqkV8nmWdakunN7Qt/JbTcKlbH3HjIyXBy8gXDaEto5ABEBAAGJAh8EGAEIAAkF Ak6TJCgCGwwACgkQaMKH38aoAiZ4lg/+N2mkx5vsBmcsZVd3ys3sIsG18w6RcJZo5SGMxEBj t1UgyIXWI9lzpKCKIxKx0bskmEyMy4tPEDSRfZno/T7p1mU7hsM4owi/ic0aGBKP025Iok9G LKJcooP/A2c9dUV0FmygecRcbIAUaeJ27gotQkiJKbi0cl2gyTRlolKbC3R23K24LUhYfx4h pWj8CHoXEJrOdHO8Y0XH7059xzv5oxnXl2SD1dqA66INnX+vpW4TD2i+eQNPgfkECzKzGj+r KRfhdDZFBJj8/e131Y0t5cu+3Vok1FzBwgQqBnkA7dhBsQm3V0R8JTtMAqJGmyOcL+JCJAca 3Yi81yLyhmYzcRASLvJmoPTsDp2kZOdGr05Dt8aGPRJL33Jm+igfd8EgcDYtG6+F8MCBOult TTAu+QAijRPZv1KhEJXwUSke9HZvzo1tNTlY3h6plBsBufELu0mnqQvHZmfa5Ay99dF+dL1H WNp62+mTeHsX6v9EACH4S+Cw9Q1qJElFEu9/1vFNBmGY2vDv14gU2xEiS2eIvKiYl/b5Y85Q QLOHWV8up73KK5Qq/6bm4BqVd1rKGI9un8kezUQNGBKre2KKs6wquH8oynDP/baoYxEGMXBg GF/qjOC6OY+U7kNUW3N/A7J3M2VdOTLu3hVTzJMZdlMmmsg74azvZDV75dUigqXcwjE= Subject: hippi: dead code issue on skb->data DMA limitations check Message-ID: Date: Wed, 18 Sep 2019 13:07:01 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi there, Static analysis with Coverity has detected an issue in rr_init1() in drivers/net/hippi/rrunner.c as follows: CID 13516 (#1 of 1): Operands don't affect result (CONSTANT_EXPRESSION_RESULT) result_independent_of_operands: ((unsigned long)skb->data & 4095) > 18446744073709486295UL /* ~0xff28 */ is always false regardless of the values of its operands. This occurs as the logical operand of if. 653 /* 654 * Sanity test to see if we conflict with the DMA 655 * limitations of the Roadrunner. 656 */ 657 if ((((unsigned long)skb->data) & 0xfff) > ~65320) CID 14371: Logically dead code (DEADCODE) 658 printk("skb alloc error\n"); 659 Given that this check is currently dead code and it's been in the driver for ages, should we just throw this check away or fix it? I'm not entirely sure what the original intent was, so I'm not clear on a fix. Colin