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From: Pavel Skripkin <paskripkin@gmail.com>
To: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>,
	Larry Finger <Larry.Finger@lwfinger.net>,
	Phillip Potter <phil@philpotter.co.uk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] staging: r8188eu: Use usb_control_msg_recv/send() in usbctrl_vendorreq()
Date: Tue, 24 Aug 2021 14:07:46 +0300	[thread overview]
Message-ID: <d5ac7cd8-dc81-732d-b583-628cd2a273cb@gmail.com> (raw)
In-Reply-To: <3198276.4iybWabFxt@localhost.localdomain>

On 8/24/21 11:53 AM, Fabio M. De Francesco wrote:
> On Tuesday, August 24, 2021 10:13:46 AM CEST Pavel Skripkin wrote:
>> On 8/24/21 1:37 AM, Fabio M. De Francesco wrote:
>> > Replace usb_control_msg() with the new usb_control_msg_recv() and
>> > usb_control_msg_send() API of USB Core in usbctrl_vendorreq().
>> > 
>> > Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
>> > ---
>> > 
>> > Thanks to Pavel Skripkin <paskripkin@gmail.com> for his review of the
>> > RFC patch.
>> >   
>> > drivers/staging/r8188eu/hal/usb_ops_linux.c | 25 ++++++++++-----------
>> > 1 file changed, 12 insertions(+), 13 deletions(-)
>> > 
>> > [...]
>> >
>> Hi, Fabio!
>> 
>> Christophe is right about semantic part. 
> 
> Hi Pavel,
> 
> I haven't yet read Christophe's message (but I'm going to do it ASAP).
> I hope he found out what is wrong with the code, what made Phil's tests
> fail.
> 
>> Also,
>> 
>> if (!status) {
>> 
>> } else {
>> 	if (status < 0) {		<-
>> 					  |
>> 	} else {			  |
>> 					  |
>> 	}				<-
>> }					
>> 
>> Extra if-else is not needed, since status can be 0 and < 0, there is no 
>> 3rd state, like it was before.
> 
> Correct, thanks!
> 
> Now I read the following from the documentation of the new API...
> 
> "Return: If successful, 0 is returned, Otherwise, a negative error number."
> 
> I'll remove that status < 0 check and whatever else is no more necessary.
> Thanks, again :)
> 
> Regards,
> 

Btw, not related to your patch, but I start think, that this check:


	if (!pIo_buf) {
		DBG_88E("[%s] pIo_buf == NULL\n", __func__);
		status = -ENOMEM;
		goto release_mutex;
	}

Should be wrapped as

	if (WARN_ON(unlikely(!pIo_buf)) {
		...
	}

Since usb_vendor_req_buf is initialized in ->probe() and I can't see 
possible calltrace, which can cause zeroing this pointer.

Something _completely_ wrong is going on if usb_vendor_req_buf is NULL, 
and we should complain loud about it. What do you think?


With regards,
Pavel Skripkin

  reply	other threads:[~2021-08-24 11:07 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-23 22:37 [PATCH 0/2] staging: r8188eu: Use new usb_control_msg_recv/send() Fabio M. De Francesco
2021-08-23 22:37 ` [PATCH 1/2] staging: r8188eu: Use usb_control_msg_recv/send() in usbctrl_vendorreq() Fabio M. De Francesco
2021-08-24  0:08   ` Phillip Potter
2021-08-24  0:31     ` Fabio M. De Francesco
2021-08-24  1:38       ` Fabio M. De Francesco
2021-08-24  2:01         ` Fabio M. De Francesco
2021-08-24  5:44           ` Christophe JAILLET
2021-08-24 10:38             ` Fabio M. De Francesco
2021-08-24 17:03               ` Christophe JAILLET
2021-08-24 21:59         ` Phillip Potter
2021-08-24  8:13   ` Pavel Skripkin
2021-08-24  8:53     ` Fabio M. De Francesco
2021-08-24 11:07       ` Pavel Skripkin [this message]
2021-08-24 12:01         ` Fabio M. De Francesco
2021-08-24 12:09           ` Pavel Skripkin
2021-08-24 14:55             ` Fabio M. De Francesco
2021-08-23 22:37 ` [PATCH 2/2] staging: r8188eu: Make some clean-ups " Fabio M. De Francesco
2021-08-24  0:10   ` Phillip Potter

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