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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 C5E70C433E0 for ; Mon, 6 Jul 2020 15:32:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CE3520720 for ; Mon, 6 Jul 2020 15:32:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729413AbgGFPcN (ORCPT ); Mon, 6 Jul 2020 11:32:13 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:60535 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729316AbgGFPcM (ORCPT ); Mon, 6 Jul 2020 11:32:12 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212]) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jsT6H-00041I-AO; Mon, 06 Jul 2020 15:32:09 +0000 Subject: Re: mvpp2: XDP TX support To: Matteo Croce , Sven Auhagen Cc: "David S. Miller" , Jakub Kicinski , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <18eb549b-d2f6-9352-582e-aec484dc95c1@canonical.com> <20200706171504.0494beba@msft-t490s.lan> From: Colin Ian King 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= Message-ID: <3a941f1e-2842-f43e-59ea-479038b75ab5@canonical.com> Date: Mon, 6 Jul 2020 16:32:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200706171504.0494beba@msft-t490s.lan> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/07/2020 16:28, Matteo Croce wrote: > On Mon, 6 Jul 2020 14:59:22 +0100 > Colin Ian King wrote: > >> Hi, >> >> Static analysis with Coverity has found a potential issue in the >> following commit: >> >> commit c2d6fe6163de80d7f7cf400ee351f56d6cdb7a5a >> Author: Matteo Croce >> Date: Thu Jul 2 16:12:43 2020 +0200 >> >> mvpp2: XDP TX support >> >> >> In source drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c in function >> mvpp2_check_pagepool_dma, analysis is as follows: >> >> >> 4486 if (!priv->percpu_pools) >> 4487 return err; >> 4488 >> CID (#1 of 1): Array compared against 0 (NO_EFFECT) >> array_null: Comparing an array to null is not useful: priv->page_pool, >> since the test will always evaluate as true. >> >> Was priv->page_pool formerly declared as a pointer? >> >> 4489 if (!priv->page_pool) >> 4490 return -ENOMEM; >> 4491 >> >> >> page_pool is declared as: >> >> struct page_pool *page_pool[MVPP2_PORT_MAX_RXQ]; >> >> ..it is an array and hence cannot be null, so the null check is >> redundant. Later on there is a reference of priv->page_pool[0], so >> was the check meant to be: >> >> if (!priv->page_pool[0]) >> >> Colin > > Hi, > > yes, the check was meant to be 'if (!priv->page_pool[0])'. > Maybe it's a copy/paste error from other points where 'page_pool' is a > local variable. > > While at it, I've found that in case a page_pool allocation fails, I > don't cleanup the previously allocated pools, and upon deallocation the > pointer isn't set back to NULL. > > I should add something like: > > @@ -548,8 +548,10 @@ static int mvpp2_bm_pool_destroy(struct device > *dev, struct mvpp2 *priv, val |= MVPP2_BM_STOP_MASK; > mvpp2_write(priv, MVPP2_BM_POOL_CTRL_REG(bm_pool->id), val); > > - if (priv->percpu_pools) > + if (priv->percpu_pools) { > page_pool_destroy(priv->page_pool[bm_pool->id]); > + priv->page_pool[bm_pool->id] = NULL; > + } > > dma_free_coherent(dev, bm_pool->size_bytes, > bm_pool->virt_addr, > @@ -609,8 +611,15 @@ static int mvpp2_bm_init(struct device *dev, > struct mvpp2 *priv) mvpp2_pools[pn].buf_num, > mvpp2_pools[pn].pkt_size, > dma_dir); > - if (IS_ERR(priv->page_pool[i])) > - return PTR_ERR(priv->page_pool[i]); > + if (IS_ERR(priv->page_pool[i])) { > + err = PTR_ERR(priv->page_pool[i]); > + > + for (i--; i >=0; i--) { > + > page_pool_destroy(priv->page_pool[i]); > + priv->page_pool[i] = NULL; > + } > + return err; > + } > } > } > > Looks sane to you? > > Regards, > Oh, good catch on the cleanups. Yes, that looks sane. Colin