[PATCH][next] wil6210: Avoid the use of one-element array

[PATCH][next] wil6210: Avoid the use of one-element array

[Gustavo A. R. Silva]

One-element arrays are being deprecated[1]. Replace the one-element
array with a simple value type 'u8 reserved'[2], once this is just
a placeholder for alignment.

[1] https://github.com/KSPP/linux/issues/79
[2] https://github.com/KSPP/linux/issues/86

Tested-by: kernel test robot <lkp@intel.com>
Link: https://github.com/GustavoARSilva/linux-hardening/blob/master/cii/0-day/wil6210-20200715.md
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/net/wireless/ath/wil6210/wmi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/wil6210/wmi.h b/drivers/net/wireless/ath/wil6210/wmi.h
index 9affa4525609..beb53cac329b 100644
--- a/drivers/net/wireless/ath/wil6210/wmi.h
+++ b/drivers/net/wireless/ath/wil6210/wmi.h
@@ -3086,7 +3086,7 @@ struct wmi_scheduling_scheme_event {
 	/* wmi_sched_scheme_failure_type */
 	u8 failure_type;
 	/* alignment to 32b */
-	u8 reserved[1];
+	u8 reserved;
 } __packed;
 
 /* WMI_RS_CFG_CMDID - deprecated */
-- 
2.27.0

Re: [PATCH][next] wil6210: Avoid the use of one-element array

[Gustavo A. R. Silva]

Hi all,

Friendly ping: who can take this? :)

Thanks
--
Gustavo

On 7/15/20 16:57, Gustavo A. R. Silva wrote:
> One-element arrays are being deprecated[1]. Replace the one-element
> array with a simple value type 'u8 reserved'[2], once this is just
> a placeholder for alignment.
> 
> [1] https://github.com/KSPP/linux/issues/79
> [2] https://github.com/KSPP/linux/issues/86
> 
> Tested-by: kernel test robot <lkp@intel.com>
> Link: https://github.com/GustavoARSilva/linux-hardening/blob/master/cii/0-day/wil6210-20200715.md
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/net/wireless/ath/wil6210/wmi.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ath/wil6210/wmi.h b/drivers/net/wireless/ath/wil6210/wmi.h
> index 9affa4525609..beb53cac329b 100644
> --- a/drivers/net/wireless/ath/wil6210/wmi.h
> +++ b/drivers/net/wireless/ath/wil6210/wmi.h
> @@ -3086,7 +3086,7 @@ struct wmi_scheduling_scheme_event {
>  	/* wmi_sched_scheme_failure_type */
>  	u8 failure_type;
>  	/* alignment to 32b */
> -	u8 reserved[1];
> +	u8 reserved;
>  } __packed;
>  
>  /* WMI_RS_CFG_CMDID - deprecated */
> 

Re: [PATCH][next] wil6210: Avoid the use of one-element array

[Kalle Valo]

"Gustavo A. R. Silva" <gustavo@embeddedor.com> writes:

> Friendly ping: who can take this? :)

I'll take this if it's ok. I have been just busy due to vacation period.

-- 
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: [PATCH][next] wil6210: Avoid the use of one-element array

[Gustavo A. R. Silva]

On 7/23/20 01:43, Kalle Valo wrote:
> "Gustavo A. R. Silva" <gustavo@embeddedor.com> writes:
> 
>> Friendly ping: who can take this? :)
> 
> I'll take this if it's ok. I have been just busy due to vacation period.
> 

Thanks, Kalle. :)

--
Gustavo

Re: [PATCH][next] wil6210: Avoid the use of one-element array

[Johannes Berg]

On Wed, 2020-07-15 at 16:57 -0500, Gustavo A. R. Silva wrote:
> One-element arrays are being deprecated[1]. Replace the one-element
> array with a simple value type 'u8 reserved'[2], once this is just
> a placeholder for alignment.
> 
> [1] https://github.com/KSPP/linux/issues/79
> [2] https://github.com/KSPP/linux/issues/86

Umm, no, you're misinterpreting this ... This has nothing to do with
variable length and isn't used that way. As you can see from your own
patch, since you're not changing any users.

johannes

Re: [PATCH][next] wil6210: Avoid the use of one-element array

[Gustavo A. R. Silva]

On 7/22/20 14:40, Johannes Berg wrote:
> On Wed, 2020-07-15 at 16:57 -0500, Gustavo A. R. Silva wrote:
>> One-element arrays are being deprecated[1]. Replace the one-element
>> array with a simple value type 'u8 reserved'[2], once this is just
>> a placeholder for alignment.
>>
>> [1] https://github.com/KSPP/linux/issues/79
>> [2] https://github.com/KSPP/linux/issues/86
> 
> Umm, no, you're misinterpreting this ... This has nothing to do with
> variable length and isn't used that way. As you can see from your own
> patch, since you're not changing any users.
> 

I understand that this 'reserved' field is being used merely for alignment
purposes:

drivers/net/wireless/ath/wil6210/wmi.h:

3080 /* WMI_SCHEDULING_SCHEME_EVENTID */
3081 struct wmi_scheduling_scheme_event {
3082         /* wmi_fw_status_e */
3083         u8 status;
3084         /* serial number given in command */
3085         u8 serial_num;
3086         /* wmi_sched_scheme_failure_type */
3087         u8 failure_type;
3088         /* alignment to 32b */
3089         u8 reserved[1];
3090 } __packed;

and that it's not being used as a variable-length array. The links are included
to inform the people about the reason why we are removing zero-length/one-element
arrays in the first place. The thing in this case is that it doesn't hurt to use
a simple value type instead of the one-element array form.

Thanks
--
Gustavo

Re: [PATCH][next] wil6210: Avoid the use of one-element array

[Kalle Valo]

"Gustavo A. R. Silva" <gustavoars@kernel.org> wrote:

> One-element arrays are being deprecated[1]. Replace the one-element
> array with a simple value type 'u8 reserved'[2], once this is just
> a placeholder for alignment.
> 
> [1] https://github.com/KSPP/linux/issues/79
> [2] https://github.com/KSPP/linux/issues/86
> 
> Tested-by: kernel test robot <lkp@intel.com>
> Link: https://github.com/GustavoARSilva/linux-hardening/blob/master/cii/0-day/wil6210-20200715.md
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

I agree with Johannes, I don't see the point of this patch as there are
no clear benefits.

Patch set to Rejected.

-- 
https://patchwork.kernel.org/patch/11666325/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches