Re: [patch] net/fec: "u32" is more explicit than "unsigned long"

David Miller
2013-08-27T18:51:44Z

From: Ben Hutchings <bhutchings@solarflare.com>
Date: Fri, 23 Aug 2013 13:44:29 +0100

> On Fri, 2013-08-23 at 12:49 +0300, Dan Carpenter wrote:
>> tmpaddr[] is a six byte array. We want to set the first four bytes on
>> the first line and the remaining two on the next line. The code assumes
>> that "unsigned long" is 32 bits and obviously that's not true on 64 bit
>> arches. It's better to just use u32 instead.
>>
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>> ---
>> This is a static checker thing and I can't compile this file.
>>
>> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
>> index fdf9307..422b125 100644
>> --- a/drivers/net/ethernet/freescale/fec_main.c
>> +++ b/drivers/net/ethernet/freescale/fec_main.c
>> @@ -1100,9 +1100,9 @@ static void fec_get_mac(struct net_device *ndev)
>> * 4) FEC mac registers set by bootloader
>> */
>> if (!is_valid_ether_addr(iap)) {
>> - *((unsigned long *) &tmpaddr[0]) >> + *((u32 *) &tmpaddr[0]) >> be32_to_cpu(readl(fep->hwp + FEC_ADDR_LOW));
>> - *((unsigned short *) &tmpaddr[4]) >> + *((u16 *) &tmpaddr[4]) >> be16_to_cpu(readl(fep->hwp + FEC_ADDR_HIGH) >> 16);
>> iap = &tmpaddr[0];
>> }
>
> This code also seems to have CPU vs big-endian byte order the wrong way
> round. readl() returns bytes in native order whereas we always store
> MAC addresses in network (big-endian) order. So I think it should be
> doing:
>
> *((__be32 *) &tmpaddr[0]) > cpu_to_be32(readl(fep->hwp + FEC_ADDR_LOW));
> *((__be16 *) &tmpaddr[4]) > cpu_to_be16(readl(fep->hwp + FEC_ADDR_HIGH) >> 16);

Dan please resubmit with Ben's suggested changes, thanks.