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From: Larry Finger <Larry.Finger@lwfinger.net>
To: Aakash Hemadri <aakashhemadri123@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Phillip Potter <phil@philpotter.co.uk>
Cc: linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/5] staging: r8188eu: cast to restricted __be32
Date: Mon, 23 Aug 2021 09:24:18 -0500	[thread overview]
Message-ID: <25d336b5-8008-9b3b-7efe-a82afaea0e98@lwfinger.net> (raw)
In-Reply-To: <20210823084426.yo2mhgbyehkwwz3h@xps.yggdrasil>

On 8/23/21 3:44 AM, Aakash Hemadri wrote:
> On 21/08/21 09:48PM, Aakash Hemadri wrote:
>> Fix sparse warning:
>>> rtw_br_ext.c:836:54: warning: cast to restricted __be32
>>
>> dhpch->cookie is be32, change it's type.
>>
>> Suggested-by: Larry Finger <Larry.Finger@lwfinger.net>
>> Signed-off-by: Aakash Hemadri <aakashhemadri123@gmail.com>
>> ---
>>   drivers/staging/r8188eu/core/rtw_br_ext.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c b/drivers/staging/r8188eu/core/rtw_br_ext.c
>> index f6d1f6029ec3..f65d94bfa286 100644
>> --- a/drivers/staging/r8188eu/core/rtw_br_ext.c
>> +++ b/drivers/staging/r8188eu/core/rtw_br_ext.c
>> @@ -649,7 +649,7 @@ struct dhcpMessage {
>>   	u_int8_t chaddr[16];
>>   	u_int8_t sname[64];
>>   	u_int8_t file[128];
>> -	u_int32_t cookie;
>> +	__be32 cookie;
>>   	u_int8_t options[308]; /* 312 - cookie */
>>   };
>>   
>> @@ -671,7 +671,7 @@ void dhcp_flag_bcast(struct adapter *priv, struct sk_buff *skb)
>>   				    (udph->dest == __constant_htons(SERVER_PORT))) { /*  DHCP request */
>>   					struct dhcpMessage *dhcph =
>>   						(struct dhcpMessage *)((size_t)udph + sizeof(struct udphdr));
>> -					u32 cookie = be32_to_cpu((__be32)dhcph->cookie);
>> +					u32 cookie = be32_to_cpu(dhcph->cookie);
>>   
>>   					if (cookie == DHCP_MAGIC) { /*  match magic word */
>>   						if (!(dhcph->flags & htons(BROADCAST_FLAG))) {
>> -- 
>> 2.32.0
>>
> 
> David Laight suggested to use get_unaligned_be32, I am not sure if it's
> the right thing to do because as far as I understand get_unaligned_be32
> byteshifts the argument.
> 
> Can someone please confirm if this change is okay?
> 

It is not needed. variable dhcph->cookie is 4-byte aligned. Usind the unaligned 
version would just add cpu cycles and arrivw at the same point!

Larry


  reply	other threads:[~2021-08-23 14:24 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-21 16:18 [PATCH v3 0/5] staging: r8188eu: fix sparse warnings Aakash Hemadri
2021-08-21 16:18 ` [PATCH v3 1/5] staging: r8188eu: restricted __be16 degrades to int Aakash Hemadri
2021-08-21 17:23   ` Phillip Potter
2021-08-21 16:18 ` [PATCH v3 2/5] staging: r8188eu: cast to restricted __be32 Aakash Hemadri
2021-08-23  8:44   ` Aakash Hemadri
2021-08-23 14:24     ` Larry Finger [this message]
2021-08-25  9:13       ` David Laight
2021-08-25  9:19         ` Dan Carpenter
2021-08-25 10:21           ` David Laight
2021-08-25 10:39             ` Dan Carpenter
2021-08-21 16:18 ` [PATCH v3 3/5] staging: r8188eu: incorrect type in csum_ipv6_magic Aakash Hemadri
2021-08-21 16:18 ` [PATCH v3 4/5] staging: r8188eu: restricted __be16 degrades to int Aakash Hemadri
2021-08-21 16:18 ` [PATCH v3 5/5] staging: r8188eu: incorrect type in assignment Aakash Hemadri
2021-08-22 20:25   ` Larry Finger
2021-08-21 16:20 ` [PATCH v3 0/5] staging: r8188eu: fix sparse warnings Greg Kroah-Hartman

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