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Date:   Thu, 26 Aug 2021 11:27:45 +0300
From:   Pavel Skripkin <paskripkin@gmail.com>
To:     David Laight <David.Laight@ACULAB.COM>
Cc:     "Larry.Finger@lwfinger.net" <Larry.Finger@lwfinger.net>,
        "phil@philpotter.co.uk" <phil@philpotter.co.uk>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
        "straube.linux@gmail.com" <straube.linux@gmail.com>,
        "fmdefrancesco@gmail.com" <fmdefrancesco@gmail.com>,
        "linux-staging@lists.linux.dev" <linux-staging@lists.linux.dev>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 3/6] staging: r8188eu: add error handling of
 rtw_read8
Message-ID: <20210826112745.5e1421ed@gmail.com>
In-Reply-To: <f5c20e0f1b934e04ad11a3627d71f5db@AcuMS.aculab.com>
References: <cover.1629789580.git.paskripkin@gmail.com>
        <c59d5d850bf9aab208704182c83086609289cb9c.1629789580.git.paskripkin@gmail.com>
        <f5c20e0f1b934e04ad11a3627d71f5db@AcuMS.aculab.com>
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On Thu, 26 Aug 2021 08:21:34 +0000
David Laight <David.Laight@ACULAB.COM> wrote:

> From: Pavel Skripkin
> > Sent: 24 August 2021 08:27
> > 
> > _rtw_read8 function can fail in case of usb transfer failure. But
> > previous function prototype wasn't designed to return an error to
> > caller. It can cause a lot uninit value bugs all across the driver
> > code, since rtw_read8() returns local stack variable to caller.
> > 
> > Fix it by changing the prototype of this function. Now it returns an
> > int: 0 on success, negative error value on failure and callers
> > should pass the pointer to storage location for register value.
> 
> ...
> > +		len += snprintf(page + len, count - len,
> > "rtw_read8(0x%x)=0x%x\n",
> > +				proc_get_read_addr, (u8) tmp);
> 
> That is broken.
> 

Don't get it, sorry. Previous code did exactly the same thing, but
didn't check if read() was successful.


With regards,
Pavel Skripkin