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=-7.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 42419C433E0 for ; Fri, 10 Jul 2020 06:33:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 094F620787 for ; Fri, 10 Jul 2020 06:33:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="luB6hwR4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727848AbgGJGdD (ORCPT ); Fri, 10 Jul 2020 02:33:03 -0400 Received: from mout.web.de ([212.227.17.12]:60185 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727050AbgGJGdB (ORCPT ); Fri, 10 Jul 2020 02:33:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1594362762; bh=VSjkdBzvkGVrNT496rxp9Bw1WUlP3ENwOMf0SJfm364=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=luB6hwR4i7nRJjgxqtglc/ZyD+mjMLPZp2iT5Cl5HTYC4JxCZ0wrGM6JrxeaPfevU PCka1t6FKs8HhoRGOsgzzoqVrOoRMjDTCbs91FE4vGwN4jscHn8Llq5WIrcRwAFkNS i+Nq9kc8/RVmJoihbj7I4RUcElpGM5+Izv6Gud5I= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.2] ([93.135.129.239]) by smtp.web.de (mrweb106 [213.165.67.124]) with ESMTPSA (Nemesis) id 1N1u6d-1krgVX0c5R-012Jmp; Fri, 10 Jul 2020 08:32:42 +0200 Subject: Re: [PATCH] scsi: virtio_scsi: Remove unnecessary condition checks To: Paolo Bonzini , Xianting Tian , linux-scsi@vger.kernel.org, virtualization@lists.linux-foundation.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, "James E. J. Bottomley" , Jason Wang , "Martin K. Petersen" , "Michael S. Tsirkin" , Stefan Hajnoczi References: From: Markus Elfring Autocrypt: addr=Markus.Elfring@web.de; prefer-encrypt=mutual; keydata= mQINBFg2+xABEADBJW2hoUoFXVFWTeKbqqif8VjszdMkriilx90WB5c0ddWQX14h6w5bT/A8 +v43YoGpDNyhgA0w9CEhuwfZrE91GocMtjLO67TAc2i2nxMc/FJRDI0OemO4VJ9RwID6ltwt mpVJgXGKkNJ1ey+QOXouzlErVvE2fRh+KXXN1Q7fSmTJlAW9XJYHS3BDHb0uRpymRSX3O+E2 lA87C7R8qAigPDZi6Z7UmwIA83ZMKXQ5stA0lhPyYgQcM7fh7V4ZYhnR0I5/qkUoxKpqaYLp YHBczVP+Zx/zHOM0KQphOMbU7X3c1pmMruoe6ti9uZzqZSLsF+NKXFEPBS665tQr66HJvZvY GMDlntZFAZ6xQvCC1r3MGoxEC1tuEa24vPCC9RZ9wk2sY5Csbva0WwYv3WKRZZBv8eIhGMxs rcpeGShRFyZ/0BYO53wZAPV1pEhGLLxd8eLN/nEWjJE0ejakPC1H/mt5F+yQBJAzz9JzbToU 5jKLu0SugNI18MspJut8AiA1M44CIWrNHXvWsQ+nnBKHDHHYZu7MoXlOmB32ndsfPthR3GSv jN7YD4Ad724H8fhRijmC1+RpuSce7w2JLj5cYj4MlccmNb8YUxsE8brY2WkXQYS8Ivse39MX BE66MQN0r5DQ6oqgoJ4gHIVBUv/ZwgcmUNS5gQkNCFA0dWXznQARAQABtCZNYXJrdXMgRWxm cmluZyA8TWFya3VzLkVsZnJpbmdAd2ViLmRlPokCVAQTAQgAPhYhBHDP0hzibeXjwQ/ITuU9 Figxg9azBQJYNvsQAhsjBQkJZgGABQsJCAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEOU9Figx g9azcyMP/iVihZkZ4VyH3/wlV3nRiXvSreqg+pGPI3c8J6DjP9zvz7QHN35zWM++1yNek7Ar OVXwuKBo18ASlYzZPTFJZwQQdkZSV+atwIzG3US50ZZ4p7VyUuDuQQVVqFlaf6qZOkwHSnk+ CeGxlDz1POSHY17VbJG2CzPuqMfgBtqIU1dODFLpFq4oIAwEOG6fxRa59qbsTLXxyw+PzRaR LIjVOit28raM83Efk07JKow8URb4u1n7k9RGAcnsM5/WMLRbDYjWTx0lJ2WO9zYwPgRykhn2 sOyJVXk9xVESGTwEPbTtfHM+4x0n0gC6GzfTMvwvZ9G6xoM0S4/+lgbaaa9t5tT/PrsvJiob kfqDrPbmSwr2G5mHnSM9M7B+w8odjmQFOwAjfcxoVIHxC4Cl/GAAKsX3KNKTspCHR0Yag78w i8duH/eEd4tB8twcqCi3aCgWoIrhjNS0myusmuA89kAWFFW5z26qNCOefovCx8drdMXQfMYv g5lRk821ZCNBosfRUvcMXoY6lTwHLIDrEfkJQtjxfdTlWQdwr0mM5ye7vd83AManSQwutgpI q+wE8CNY2VN9xAlE7OhcmWXlnAw3MJLW863SXdGlnkA3N+U4BoKQSIToGuXARQ14IMNvfeKX NphLPpUUnUNdfxAHu/S3tPTc/E/oePbHo794dnEm57LuuQINBFg2+xABEADZg/T+4o5qj4cw nd0G5pFy7ACxk28mSrLuva9tyzqPgRZ2bdPiwNXJUvBg1es2u81urekeUvGvnERB/TKekp25 4wU3I2lEhIXj5NVdLc6eU5czZQs4YEZbu1U5iqhhZmKhlLrhLlZv2whLOXRlLwi4jAzXIZAu 76mT813jbczl2dwxFxcT8XRzk9+dwzNTdOg75683uinMgskiiul+dzd6sumdOhRZR7YBT+xC wzfykOgBKnzfFscMwKR0iuHNB+VdEnZw80XGZi4N1ku81DHxmo2HG3icg7CwO1ih2jx8ik0r riIyMhJrTXgR1hF6kQnX7p2mXe6K0s8tQFK0ZZmYpZuGYYsV05OvU8yqrRVL/GYvy4Xgplm3 DuMuC7/A9/BfmxZVEPAS1gW6QQ8vSO4zf60zREKoSNYeiv+tURM2KOEj8tCMZN3k3sNASfoG fMvTvOjT0yzMbJsI1jwLwy5uA2JVdSLoWzBD8awZ2X/eCU9YDZeGuWmxzIHvkuMj8FfX8cK/ 2m437UA877eqmcgiEy/3B7XeHUipOL83gjfq4ETzVmxVswkVvZvR6j2blQVr+MhCZPq83Ota xNB7QptPxJuNRZ49gtT6uQkyGI+2daXqkj/Mot5tKxNKtM1Vbr/3b+AEMA7qLz7QjhgGJcie qp4b0gELjY1Oe9dBAXMiDwARAQABiQI8BBgBCAAmFiEEcM/SHOJt5ePBD8hO5T0WKDGD1rMF Alg2+xACGwwFCQlmAYAACgkQ5T0WKDGD1rOYSw/+P6fYSZjTJDAl9XNfXRjRRyJSfaw6N1pA Ahuu0MIa3djFRuFCrAHUaaFZf5V2iW5xhGnrhDwE1Ksf7tlstSne/G0a+Ef7vhUyeTn6U/0m +/BrsCsBUXhqeNuraGUtaleatQijXfuemUwgB+mE3B0SobE601XLo6MYIhPh8MG32MKO5kOY hB5jzyor7WoN3ETVNQoGgMzPVWIRElwpcXr+yGoTLAOpG7nkAUBBj9n9TPpSdt/npfok9ZfL /Q+ranrxb2Cy4tvOPxeVfR58XveX85ICrW9VHPVq9sJf/a24bMm6+qEg1V/G7u/AM3fM8U2m tdrTqOrfxklZ7beppGKzC1/WLrcr072vrdiN0icyOHQlfWmaPv0pUnW3AwtiMYngT96BevfA qlwaymjPTvH+cTXScnbydfOQW8220JQwykUe+sHRZfAF5TS2YCkQvsyf7vIpSqo/ttDk4+xc Z/wsLiWTgKlih2QYULvW61XU+mWsK8+ZlYUrRMpkauN4CJ5yTpvp+Orcz5KixHQmc5tbkLWf x0n1QFc1xxJhbzN+r9djSGGN/5IBDfUqSANC8cWzHpWaHmSuU3JSAMB/N+yQjIad2ztTckZY pwT6oxng29LzZspTYUEzMz3wK2jQHw+U66qBFk8whA7B2uAU1QdGyPgahLYSOa4XAEGb6wbI FEE= Message-ID: <8eb9a827-45f1-e71c-0cbf-1c29acd8e310@web.de> Date: Fri, 10 Jul 2020 08:32:33 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:FX8FryPsmDViqZC962m+4pWDswlnK0V23fb+GXCb9B8DsrzKIVX /Gpa47Lg1rGyg9CeIk40gidvRDCiBv/8l/d89KQtqdM8s1gtegZW2Us4yxQ3+5z9P98S6km 5Ga5Nh5MU6nbh6D3AWdoK6YjbjWz2iVZya5SIBrjxfzh2MotWESRdx2/8ko/HagQjZn46Gv o1Mca4OZXEV8z4JFGZWCA== X-UI-Out-Filterresults: notjunk:1;V03:K0:GzZE6VK4dOQ=:t83HzhaOTridvOKZEMYg4s 37je6YWVvcLbOOeADbRW293V13Skt9rKaCjupP6EDdG5Yo3fXCvhdsz4QsOaDAhvf2lZJYvLw eABTTxVWPSeQ8+1gNzHIWf/Kh7yHLDjqEynFnX1qc7E6qGm5M255uWQdH6OHn4xeXYYG2lMuL nUKRAENTDtZhssKrwAurgRCABZAn9/B6darxqgvrnJeYWme1ZeFke6xxW3bibQyc1CAAtdG+6 KNZqHajoAfIGP2fBzh1Q1UUofwtKjjya+Dyc7FyIwLWT1+JwNQIfFGQnbzs1RXKa7FfzneiVM xMjilyCMNd3aZrIt6GdKTeLyDwFQ3ygVbtjS7xtmyjGk3srowDcF36OPWf+XuawMYGpKJray3 hv+D8F9z0FjWCecV7qQGOsuBVTki8FDJXpSVmLnemkngS7MDP5igzBDNCLPLy1TVuiZwnl947 OpRbRBGmX6/x3nH5XBAbPZviVQs4XB95HMNCiD5tOQAJxp5Fif3ba3PVmez1v3ez5BBkA35yy ih7ihcLip9xXoHoMsBAjVUOSiygCh2W2wBKuYfk8cE6iQ3F/+EVUURAj8+P2VSNryfgk7zVn7 6DsyS0yhGSbi4/Z78nW5aFCg7cgJnNhbqOY1wP9IQEmYJ1wY/VH4LRCxrO0m1Tf9PIq+HeLNS KQWK/1BXDyvizekBx2AmRE6c5O0R3ySHWtRI8JbnuDxhzzolv9ZrZxVVfI8y1R0qX8+a+jP+A VXXkARNs5US0hCzukvqtXP+OQi7D0e5NsWeoA9dvi6GzS6fEiHjJHILbW1XXueQW5Y1q87NyN i3zce6VY5Mm/QWUSyrNzrhMjdmjjKfja4Gn6MjRWsVsvl5fGOKJFgi+lNFplfDOVsEiuVpIrr aYZmbpwYT+nZQ0qVNi9U+d3K4aV6f5TJ22Gt/FoGgMw8YkY78cARo4ABVGZKFdvvKtEqj8a1y YgOC3+gjjw892t6It2ygotT8skx22qXtbrmBQEr3oz26gj3oIFiJgy4R13lX3k0UzBVptEPXO uSHZsOSA2ElSChxDsgBtVR8pBvKYEGpRkAvaUvHYYs9F7qswVd/GV3e43PlKzLUOF1mkmBJlY V3uV5HJ3pWmC9JmhhL/8fZHLqHJrhGVCqS+v/6FCs4Ad9ZhXYUIYPupcxKG/UpnjjvQeeJzVo lwxUypPvrnrgLsxNM2JsMP6BSThb4CxujB0rB19MChinhdJvINDZ2n/eJ51otPCe2RzszVjkT z3+KgY7HKaOr7Pzx03aSZpVQh0YeVF3ObYPgAQQ== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> + mempool_destroy(virtscsi_cmd_pool); >>> + virtscsi_cmd_pool =3D NULL; >>> + kmem_cache_destroy(virtscsi_cmd_cache); >>> + virtscsi_cmd_cache =3D NULL; >>> return ret; >>> } >> >> How do you think about to add a jump target so that the execution >> of a few statements can be avoided according to a previous >> null pointer check? > > The point of the patch is precisely to simplify the code, I suggest to reconsider also Linux coding style aspects for the implementation of the function =E2=80=9Cinit=E2=80=9D. https://elixir.bootlin.com/linux/v5.8-rc4/source/drivers/scsi/virtio_scsi.= c#L980 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/dr= ivers/scsi/virtio_scsi.c?id=3D42f82040ee66db13525dc6f14b8559890b2f4c1c#n98= 0 if (!virtscsi_cmd_cache) { pr_err("kmem_cache_create() for virtscsi_cmd_cache failed\n"); - goto error; + return -ENOMEM; } See also: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Do= cumentation/process/coding-style.rst?id=3D42f82040ee66db13525dc6f14b855989= 0b2f4c1c#n461 > executing a couple more instruction is not an issue. With which update steps would like to achieve such a code variant? destroy_pool: mempool_destroy(virtscsi_cmd_pool); virtscsi_cmd_pool =3D NULL; destroy_cache: kmem_cache_destroy(virtscsi_cmd_cache); virtscsi_cmd_cache =3D NULL; return ret; Regards, Markus