Re: [PATCH v3 2/3] wifi: rtl8xxxu: Fix the channel width reporting

[Bitterblue Smith <rtl8821cerfe2@gmail.com>]

On 30/11/2022 02:38, Ping-Ke Shih wrote:
> 
> 
>> -----Original Message-----
>> From: Bitterblue Smith <rtl8821cerfe2@gmail.com>
>> Sent: Wednesday, November 30, 2022 3:06 AM
>> To: linux-wireless@vger.kernel.org
>> Cc: Jes Sorensen <Jes.Sorensen@gmail.com>; Ping-Ke Shih <pkshih@realtek.com>
>> Subject: [PATCH v3 2/3] wifi: rtl8xxxu: Fix the channel width reporting
>>
>> The gen 2 chips RTL8192EU and RTL8188FU periodically send the driver
>> reports about the TX rate, and the driver passes these reports to
>> sta_statistics. The reports from RTL8192EU may or may not include the
>> channel width. The reports from RTL8188FU do not include it.
>>
>> Only access the c2h->ra_report.bw field if the report (skb) is big
>> enough.
>>
>> The other problem fixed here is that the code was actually never
>> changing the channel width initially reported by
>> rtl8xxxu_bss_info_changed because the value of RATE_INFO_BW_20 is 0.
>>
>> Fixes: 0985d3a410ac ("rtl8xxxu: Feed current txrate information for mac80211")
>> Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
>> ---
>> v3:
>>  - Don't assume bw will always be 1 byte.
>>
>> v2:
>>  - Eliminate the magic numbers.
>> ---
>>  drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 11 ++++++++---
>>  1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> index 28f136064297..9799bc5ed60a 100644
>> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> @@ -5569,7 +5569,6 @@ static void rtl8xxxu_c2hcmd_callback(struct work_struct *work)
>>  			rarpt->txrate.flags = 0;
>>  			rate = c2h->ra_report.rate;
>>  			sgi = c2h->ra_report.sgi;
>> -			bw = c2h->ra_report.bw;
>>
>>  			if (rate < DESC_RATE_MCS0) {
>>  				rarpt->txrate.legacy =
>> @@ -5586,8 +5585,14 @@ static void rtl8xxxu_c2hcmd_callback(struct work_struct *work)
>>  						RATE_INFO_FLAGS_SHORT_GI;
>>  				}
>>
>> -				if (bw == RATE_INFO_BW_20)
>> -					rarpt->txrate.bw |= RATE_INFO_BW_20;
>> +				if (skb->len >= offsetof(typeof(*c2h), ra_report.bw) +
>> +						sizeof(c2h->ra_report.bw)) {
> 
> Today, I look up if we have a better choice, and offsetofend() can make thing simple.
> 
> if (skb->len >= offsetofend(typeof(*c2h), ra_report.bw))
> 
> Sorry for the late.
> 

Even better. Thank you.