linux-kernel - Re: [PATCH 05/14] staging: r8188eu: use a local buffer for efuse data

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Message-ID: <28adfbda-4820-d6e4-cacd-8e1ef89a841d@lwfinger.net>
Date:   Tue, 12 Jul 2022 08:45:40 -0500
From:   Larry Finger <Larry.Finger@...inger.net>
To:     Dan Carpenter <dan.carpenter@...cle.com>,
        Martin Kaiser <martin@...ser.cx>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Michael Straube <straube.linux@...il.com>,
        Pavel Skripkin <paskripkin@...il.com>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 05/14] staging: r8188eu: use a local buffer for efuse data

On 7/12/22 07:25, Dan Carpenter wrote:
> On Sat, Jul 09, 2022 at 07:09:51PM +0200, Martin Kaiser wrote:
>> The efuse_eeprom_data array in struct eeprom_priv is used only by
>> ReadAdapterInfo8188EU. We can remove efuse_eeprom_data and use a local
>> buffer instead.
>>
>> Use EFUSE_MAP_LEN_88E as buffer size. Its value is the same as
>> HWSET_MAX_SIZE_512. The functions that access the buffer use
>> EFUSE_MAP_LEN_88E for its size.
>>
>> Signed-off-by: Martin Kaiser <martin@...ser.cx>
>> ---
>>   drivers/staging/r8188eu/hal/usb_halinit.c    | 23 ++++++++++----------
>>   drivers/staging/r8188eu/include/rtw_eeprom.h |  3 ---
>>   2 files changed, 12 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/staging/r8188eu/hal/usb_halinit.c b/drivers/staging/r8188eu/hal/usb_halinit.c
>> index 18c2817bf1e3..807d8ce8cbfc 100644
>> --- a/drivers/staging/r8188eu/hal/usb_halinit.c
>> +++ b/drivers/staging/r8188eu/hal/usb_halinit.c
>> @@ -929,6 +929,7 @@ void ReadAdapterInfo8188EU(struct adapter *Adapter)
>>   {
>>   	struct eeprom_priv *eeprom = &Adapter->eeprompriv;
>>   	struct led_priv *ledpriv = &Adapter->ledpriv;
>> +	u8 efuse_buf[EFUSE_MAP_LEN_88E] __aligned(4);
> 
> This is 512 bytes.  We used to be slightly worried about declaring 512
> bytes on the stack, but I'm not sure the situation now.
> 

I think we should still avoid using an on-stack buffer of that size. It is 
better to use a local pointer, and kmalloc() the buffer and free it before exit.

Larry