linux-kernel - Re: [char-misc-next] Revert "mei: hdcp: Replace one-element array with flexible-array member"

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Message-ID: <d6ef8ca4-6e11-b758-0e24-75301e1a5303@embeddedor.com>
Date:   Tue, 28 Jul 2020 17:14:36 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     "Winkler, Tomas" <tomas.winkler@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     "Usyskin, Alexander" <alexander.usyskin@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>
Subject: Re: [char-misc-next] Revert "mei: hdcp: Replace one-element array
 with flexible-array member"



On 7/28/20 17:01, Winkler, Tomas wrote:
> 
> 
>> -----Original Message-----
>> From: Gustavo A. R. Silva <gustavo@...eddedor.com>
>> Sent: Wednesday, July 29, 2020 00:57
>> To: Winkler, Tomas <tomas.winkler@...el.com>; Greg Kroah-Hartman
>> <gregkh@...uxfoundation.org>
>> Cc: Usyskin, Alexander <alexander.usyskin@...el.com>; linux-
>> kernel@...r.kernel.org; Gustavo A . R . Silva <gustavoars@...nel.org>
>> Subject: Re: [char-misc-next] Revert "mei: hdcp: Replace one-element array
>> with flexible-array member"
>>
>> Hi Tomas,
>>
>> On 7/28/20 16:41, Tomas Winkler wrote:
>>> Greg please revert, this commit it changes size of struct
>>> wired_cmd_repeater_auth_stream_req_in, this is not what firmware is
>>> expecting.
>>
>> Could you elaborate on what's the firmware expecting, exactly?
> struct wired_cmd_repeater_auth_stream_req_in {
>   -	struct hdcp2_streamid_type	streams[1];
>   + 	struct hdcp2_streamid_type	streams[];
> }
> 
> But then you have, which you haven't changed to + 1
> byte = mei_cldev_send(cldev, (u8 *)&verify_mprime_in,
>                               sizeof(verify_mprime_in));
> 

I see, this is the kind of feedback I need from people that knows the
code better. Thanks!

> But that's not the major point. Point is that we should be able to review
> and test the code before it is merged.  You haven't run it, right? 
> There is MAINTAINERS file for a reason. 
> 

I'm using this command:

$ scripts/get_maintainer.pl --nokeywords --nogit --nogit-fallback

and this is the output for both files:

$ scripts/get_maintainer.pl --nokeywords --nogit --nogit-fallback drivers/misc/mei/hdcp/mei_hdcp.c
Arnd Bergmann <arnd@...db.de> (supporter:CHAR and MISC DRIVERS)
Greg Kroah-Hartman <gregkh@...uxfoundation.org> (supporter:CHAR and MISC DRIVERS)
linux-kernel@...r.kernel.org (open list)
$ scripts/get_maintainer.pl --nokeywords --nogit --nogit-fallback drivers/misc/mei/hdcp/mei_hdcp.h
Arnd Bergmann <arnd@...db.de> (supporter:CHAR and MISC DRIVERS)
Greg Kroah-Hartman <gregkh@...uxfoundation.org> (supporter:CHAR and MISC DRIVERS)
linux-kernel@...r.kernel.org (open list)

For some reason you don't appear on the list above. Do you see anything wrong with
the command I'm running to get the maintainers and lists?

Thanks
--
Gustavo

>>
>>> I really do not appreciate that the code is bypassing driver maintaner
>>> review, I think this is a minimum we can ask for, this is not for a
>>> first time.
>>>
>>> This reverts commit c56967d674e361ebe716e66992e3c5332b25ac1f.
>>>
>>> Cc: Gustavo A. R. Silva <gustavoars@...nel.org>
>>> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
>>> ---
>>>  drivers/misc/mei/hdcp/mei_hdcp.c | 2 +-
>>> drivers/misc/mei/hdcp/mei_hdcp.h | 2 +-
>>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/misc/mei/hdcp/mei_hdcp.c
>>> b/drivers/misc/mei/hdcp/mei_hdcp.c
>>> index d1d3e025ca0e..e6c3dc595617 100644
>>> --- a/drivers/misc/mei/hdcp/mei_hdcp.c
>>> +++ b/drivers/misc/mei/hdcp/mei_hdcp.c
>>> @@ -572,7 +572,7 @@ static int mei_hdcp_verify_mprime(struct device
>> *dev,
>>>  	       HDCP_2_2_MPRIME_LEN);
>>>  	drm_hdcp_cpu_to_be24(verify_mprime_in.seq_num_m, data-
>>> seq_num_m);
>>>  	memcpy(verify_mprime_in.streams, data->streams,
>>> -	       array_size(data->k, sizeof(*data->streams)));
>>> +	       (data->k * sizeof(struct hdcp2_streamid_type)));
>>>
>>>  	verify_mprime_in.k = cpu_to_be16(data->k);
>>>
>>> diff --git a/drivers/misc/mei/hdcp/mei_hdcp.h
>>> b/drivers/misc/mei/hdcp/mei_hdcp.h
>>> index 834757f5e072..18ffc773fa18 100644
>>> --- a/drivers/misc/mei/hdcp/mei_hdcp.h
>>> +++ b/drivers/misc/mei/hdcp/mei_hdcp.h
>>> @@ -358,7 +358,7 @@ struct wired_cmd_repeater_auth_stream_req_in {
>>>  	u8
>> 	seq_num_m[HDCP_2_2_SEQ_NUM_LEN];
>>>  	u8				m_prime[HDCP_2_2_MPRIME_LEN];
>>>  	__be16				k;
>>> -	struct hdcp2_streamid_type	streams[];
>>> +	struct hdcp2_streamid_type	streams[1];
>>>  } __packed;
>>>
>>>  struct wired_cmd_repeater_auth_stream_req_out {
>>>