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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 BB17CC433DF for ; Wed, 3 Jun 2020 15:10:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 95621206E6 for ; Wed, 3 Jun 2020 15:10:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726138AbgFCPKs (ORCPT ); Wed, 3 Jun 2020 11:10:48 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:55274 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725867AbgFCPKr (ORCPT ); Wed, 3 Jun 2020 11:10:47 -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 1jgV2S-0002Mm-R3; Wed, 03 Jun 2020 15:10:44 +0000 Subject: Re: [PATCH] input: ims-pcu: remove redundant assignment to variable 'error' To: Dan Carpenter Cc: Dmitry Torokhov , linux-input@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200603135102.130436-1-colin.king@canonical.com> <20200603140953.GL30374@kadam> <20200603144507.GM30374@kadam> 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: Date: Wed, 3 Jun 2020 16:10:44 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <20200603144507.GM30374@kadam> 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 03/06/2020 15:45, Dan Carpenter wrote: > On Wed, Jun 03, 2020 at 03:18:46PM +0100, Colin Ian King wrote: >> On 03/06/2020 15:09, Dan Carpenter wrote: >>> On Wed, Jun 03, 2020 at 02:51:02PM +0100, Colin King wrote: >>>> From: Colin Ian King >>>> >>>> The variable error is being initialized with a value that is >>>> never read and the -ENOMEM error return is being returned anyhow >>>> by the error exit path to label err_free_mem. The assignment is >>>> redundant and can be removed. >>>> >>>> Addresses-Coverity: ("Unused value") >>>> Signed-off-by: Colin Ian King >>>> --- >>>> drivers/input/misc/ims-pcu.c | 1 - >>>> 1 file changed, 1 deletion(-) >>>> >>>> diff --git a/drivers/input/misc/ims-pcu.c b/drivers/input/misc/ims-pcu.c >>>> index d8dbfc030d0f..4ba68aa3d281 100644 >>>> --- a/drivers/input/misc/ims-pcu.c >>>> +++ b/drivers/input/misc/ims-pcu.c >>>> @@ -292,7 +292,6 @@ static int ims_pcu_setup_gamepad(struct ims_pcu *pcu) >>>> if (!gamepad || !input) { >>>> dev_err(pcu->dev, >>>> "Not enough memory for gamepad device\n"); >>>> - error = -ENOMEM; >>>> goto err_free_mem; >>> >>> It would be better to change the return instead. >>> >>> regards, >>> dan carpenter >>> >> >> I'm not sure about that, the err_free_mem path is used by another error >> exit return path that also needs to free the device and gamepad and >> returns ENOMEM, so I think this is a good enough shared error exit strategy. > > The code looks like this: > > drivers/input/misc/ims-pcu.c > 284 static int ims_pcu_setup_gamepad(struct ims_pcu *pcu) > 285 { > 286 struct ims_pcu_gamepad *gamepad; > 287 struct input_dev *input; > 288 int error; > 289 > 290 gamepad = kzalloc(sizeof(struct ims_pcu_gamepad), GFP_KERNEL); > 291 input = input_allocate_device(); > 292 if (!gamepad || !input) { > 293 dev_err(pcu->dev, > 294 "Not enough memory for gamepad device\n"); > 295 error = -ENOMEM; > 296 goto err_free_mem; > > The "error" is always set before all the gotos. > > 297 } > 298 > 299 gamepad->input = input; > 300 > 301 snprintf(gamepad->name, sizeof(gamepad->name), > 302 "IMS PCU#%d Gamepad Interface", pcu->device_no); > 303 > 304 usb_make_path(pcu->udev, gamepad->phys, sizeof(gamepad->phys)); > 305 strlcat(gamepad->phys, "/input1", sizeof(gamepad->phys)); > 306 > 307 input->name = gamepad->name; > 308 input->phys = gamepad->phys; > 309 usb_to_input_id(pcu->udev, &input->id); > 310 input->dev.parent = &pcu->ctrl_intf->dev; > 311 > 312 __set_bit(EV_KEY, input->evbit); > 313 __set_bit(BTN_A, input->keybit); > 314 __set_bit(BTN_B, input->keybit); > 315 __set_bit(BTN_X, input->keybit); > 316 __set_bit(BTN_Y, input->keybit); > 317 __set_bit(BTN_START, input->keybit); > 318 __set_bit(BTN_SELECT, input->keybit); > 319 > 320 __set_bit(EV_ABS, input->evbit); > 321 input_set_abs_params(input, ABS_X, -1, 1, 0, 0); > 322 input_set_abs_params(input, ABS_Y, -1, 1, 0, 0); > 323 > 324 error = input_register_device(input); > 325 if (error) { > 326 dev_err(pcu->dev, > 327 "Failed to register gamepad input device: %d\n", > 328 error); > 329 goto err_free_mem; > > The input_register_device() can return a bunch of different error codes. > Better to preserve them. "error" is set. > > 330 } > 331 > 332 pcu->gamepad = gamepad; > 333 return 0; > 334 > 335 err_free_mem: > 336 input_free_device(input); > 337 kfree(gamepad); > 338 return -ENOMEM; > > We just change this from "return -ENOMEM;" to "return error;" > > 339 } > > regards, > dan carpenter > Elegantly explained, thanks Dan, I'll send a V2. Colin