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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7036C433EF for ; Sun, 9 Jan 2022 15:50:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234248AbiAIPt7 (ORCPT ); Sun, 9 Jan 2022 10:49:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230135AbiAIPt6 (ORCPT ); Sun, 9 Jan 2022 10:49:58 -0500 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB3CCC06173F for ; Sun, 9 Jan 2022 07:49:58 -0800 (PST) Received: by mail-pf1-x42a.google.com with SMTP id m1so8628211pfk.8 for ; Sun, 09 Jan 2022 07:49:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=501hrPPR2NA197ryGJ1qflWENP5i8cayYWfphaqX6q8=; b=NQkiFS3thn2czIYZuz0IHrcv4L8CaUwVoAH3KWGMuccrANsZ+hCc18qWqWyoyrJ8Bl UTtjk4CogHRknOdLY3WDcyGSJva8S3sHfiQiOmNJDDmi0YqC5Qy0kUyzUCome1Qvt0bf p56LomVPt/8xreogJ1kVh/1C8Trl6Sa8+95f79K543qFfVph0i7RLHthfFwQpMcaZ62N Iv89wWL0bthKjb1Iu24GMeJD6iVe4Gqli92KVM3yIXwGgQXPvOMZzHY0MgrlVn+XM4j7 F2Yjsvtn6nU11uQ6oqKb0K6RZAgOcjwyOWs92M8fwQJKBVTzxhueBmhnNgA0uRe6tjaS MWuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=501hrPPR2NA197ryGJ1qflWENP5i8cayYWfphaqX6q8=; b=PEuFYmBjLnZK2qFxI8uYrBRog5uzgnURFP7/E5KYGFqDsINL8WTzMeqr4QN2E1O12K QNgluGSrExvVZRmhqafDo2L6sfu704UFr0wiLWqXZuWF4fvz7sz5Vge897+lv0gXXQBS 4bSt3vx5r/BWNJUQptLU3YIg74VzvXe861fBwE+/pqW3F+wpMxBx+f/lwmMsVw/Rg+m7 nM5lAWTeOSp9Y9bcpLE/1T4wzBvR1aKWtxETprwXRuPI3a4COWrYOEgdvDEH8mQilFZQ rDB2Clarb/PYW9jrIugs0cNDBJrlKAMUycHKcrG5jh2jXbcvpWB5ENb3hh0E5DPkUn57 6/6w== X-Gm-Message-State: AOAM531szmkgm7G4xPwwt2JZRtQERyw6qiu6r7vt2h3HeK91lCM7kfgR /5O5227rpCM88MNQwRNGQsU= X-Google-Smtp-Source: ABdhPJwbnjU5708553O1rPJMIrLe79sBqcsILgX2F7IMK6ZajDCq1PcISmwQWKan6N8poqMRi72AfA== X-Received: by 2002:a65:460c:: with SMTP id v12mr62315121pgq.58.1641743398140; Sun, 09 Jan 2022 07:49:58 -0800 (PST) Received: from realwakka ([59.12.165.26]) by smtp.gmail.com with ESMTPSA id q9sm3320011pgv.71.2022.01.09.07.49.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 09 Jan 2022 07:49:57 -0800 (PST) Date: Sun, 9 Jan 2022 15:49:50 +0000 From: Sidong Yang To: Paulo Miguel Almeida Cc: gregkh@linuxfoundation.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] staging: pi433: enforce tx_cfg to be set before any message can be sent Message-ID: <20220109154950.GA27767@realwakka> References: <20220108222652.GA11883@mail.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220108222652.GA11883@mail.google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 09, 2022 at 11:26:52AM +1300, Paulo Miguel Almeida wrote: Hi, Paulo. Thanks for the patch. I have some opinion below. > this driver relies on exposing a char device to userspace to tx > messages. Every message can be sent using different trasmitter settings > such so the tx_cfg must be written before sending any messages. > Failing to do so will cause the message to fail silently depending on > printk/dynamic_debug settings which makes it hard to troubleshoot. > > This patch add a control variable that will get initialized once tx_cfg > is set for the fd used when interacting with the char device. I don't know that adding flag is good idea. It seems that initializing to default is better than this. > > Signed-off-by: Paulo Miguel Almeida > --- > Patch dependency: > - This patch needs the patch below to be applied first as both tweak the > same file. > https://lore.kernel.org/lkml/20220108212728.GA7784@mail.google.com/ > > meta-comments: > - I'm not entirely sure if -EPERM is the best error code to return here, > I'm taking suggestions > --- > drivers/staging/pi433/pi433_if.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/drivers/staging/pi433/pi433_if.c b/drivers/staging/pi433/pi433_if.c > index 051c9052aeeb..3e9913f4bc7d 100644 > --- a/drivers/staging/pi433/pi433_if.c > +++ b/drivers/staging/pi433/pi433_if.c > @@ -108,6 +108,9 @@ struct pi433_device { > struct pi433_instance { > struct pi433_device *device; > struct pi433_tx_cfg tx_cfg; > + > + /* control flags */ > + bool tx_cfg_initialized; > }; > > /*-------------------------------------------------------------------------*/ > @@ -823,6 +826,16 @@ pi433_write(struct file *filp, const char __user *buf, > if (count > MAX_MSG_SIZE) > return -EMSGSIZE; > > + /* > + * check if tx_cfg has been initialized otherwise we won't be able to > + * config the RF trasmitter correctly due to invalid settings > + */ > + if (!instance->tx_cfg_initialized) { > + dev_dbg(device->dev, > + "write: failed due to uninitialized tx_cfg"); > + return -EPERM; > + } > + > /* > * write the following sequence into fifo: > * - tx_cfg > @@ -897,6 +910,7 @@ pi433_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) > return -EFAULT; > mutex_lock(&device->tx_fifo_lock); > memcpy(&instance->tx_cfg, &tx_cfg, sizeof(struct pi433_tx_cfg)); > + instance->tx_cfg_initialized = true; > mutex_unlock(&device->tx_fifo_lock); > break; > case PI433_IOC_RD_RX_CFG: > @@ -950,7 +964,7 @@ static int pi433_open(struct inode *inode, struct file *filp) > /* setup instance data*/ > instance->device = device; > instance->tx_cfg.bit_rate = 4711; > - // TODO: fill instance->tx_cfg; > + instance->tx_cfg_initialized = false; > > /* instance data as context */ > filp->private_data = instance; > -- > 2.25.4 >