linux-kernel - Re: [PATCH] wifi: rtl8xxxu: correct the error value of 'timeout'

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <9c90dd30-448c-6d1c-76e4-85b36eb739f9@nfschina.com>
Date:   Tue, 14 Nov 2023 17:17:50 +0800
From:   Su Hui <suhui@...china.com>
To:     Ping-Ke Shih <pkshih@...ltek.com>,
        "Jes.Sorensen@...il.com" <Jes.Sorensen@...il.com>,
        "kvalo@...nel.org" <kvalo@...nel.org>
Cc:     "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kernel-janitors@...r.kernel.org" <kernel-janitors@...r.kernel.org>
Subject: Re: [PATCH] wifi: rtl8xxxu: correct the error value of 'timeout'

On 2023/11/14 14:42, Ping-Ke Shih wrote:
>> -----Original Message-----
>> From: Su Hui <suhui@...china.com>
>> Sent: Monday, November 13, 2023 1:49 PM
>> To: Jes.Sorensen@...il.com; kvalo@...nel.org
>> Cc: Su Hui <suhui@...china.com>; linux-wireless@...r.kernel.org; linux-kernel@...r.kernel.org;
>> kernel-janitors@...r.kernel.org
>> Subject: [PATCH] wifi: rtl8xxxu: correct the error value of 'timeout'
>>
>> When 'rtl8xxxu_dma_agg_pages <= page_thresh', 'timeout' should equal to
>> 'page_thresh' rather than '4'. Change the code order to fix this problem.
>>
>> Fixes: 614e389f36a9 ("rtl8xxxu: gen1: Set aggregation timeout (REG_RXDMA_AGG_PG_TH + 1) as well")
> I think this should fix
> Fixes: fd83f1227826 ("rtl8xxxu: gen1: Add module parameters to adjust DMA aggregation parameters")
Agreed. Thanks for your reminder!
>
>> Signed-off-by: Su Hui <suhui@...china.com>
>> ---
>>   .../net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c    | 12 ++++++------
>>   1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> index 43ee7592bc6e..9cab8b1dc486 100644
>> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> @@ -4757,6 +4757,12 @@ void rtl8xxxu_gen1_init_aggregation(struct rtl8xxxu_priv *priv)
>>           *   RxAggPageTimeout = 4 or 6 (absolute time 34ms/(2^6))
>>           */
>>
>> +       /* REG_RXDMA_AGG_PG_TH + 1 seems to be the timeout register on
>> +        * gen2 chips and rtl8188eu. The rtl8723au seems unhappy if we
>> +        * don't set it, so better set both.
>> +        */
>> +       timeout = 4;
>> +
>>          page_thresh = (priv->fops->rx_agg_buf_size / 512);
>>          if (rtl8xxxu_dma_agg_pages >= 0) {
>>                  if (rtl8xxxu_dma_agg_pages <= page_thresh)
> The logic here is:
>
> 	page_thresh = (priv->fops->rx_agg_buf_size / 512);
> 	if (rtl8xxxu_dma_agg_pages >= 0) {
> 		if (rtl8xxxu_dma_agg_pages <= page_thresh)
> 			timeout = page_thresh;
>
> Do you know why 'timeout = page_thresh;'? Intuitively, units of 'timeout' and
> 'thresh' are different. Maybe, we should correct here instead?
I don't know the reason about this. :(
I found this error because clang static checker complains about this 
code that value stored to 'timeout'
is never read.

Su Hui