Re: [PATCH v4 02/35] staging: rtl8192e: Declare ethernet addresses as __aligned(2)

Mateusz Kulikowski
2015-05-26T20:25:47Z

On 25.05.2015 15:53, Dan Carpenter wrote:
> On Thu, May 21, 2015 at 05:53:15PM +0200, Mateusz Kulikowski wrote:
>> Add __aligned(2) into ethernet addresses allocated on stack or in non-packed
>> structures. Use ETH_ALEN as array length in places where it was hardcoded to 6.
>
> To be honest, this patch makes me hate the stupid ether_addr_copy()
> checkpatch warnings even more than I hated it before. Do we really need
> to add __aligned(2) to everything? Is there no other option which isn't
> as horrible?
>
> We could introduce a new typedef:
>
> typedef struct {
> char addr[6] __aligned(2);
> } eth_addr_t;
>
> Introducing a new kind of type is maybe a bit much just to make
> checkpatch.pl happy but so is putting __aligned(2) everywhere.

True. I was a bit overzealous here with __aligned(2) and assumed someone will
break it by accident.

Proposal for v5: I'll verify alignment of each array,
and reorder variables where possible/needed to keep the alignment.
Then I'll hopefully drop this patch.

> Or maybe we could make a new ether_addr_copy() implementation that uses
> preprocessor macros and chooses the right kind of implementation?

I'm not sure it can be handled compile time for generic case.

>
>> diff --git a/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c b/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c
>> index aad5cc9..9c6dc82 100644
>> --- a/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c
>> +++ b/drivers/staging/rtl8192e/rtl8192e/r8192E_dev.c
>> @@ -321,7 +321,9 @@ static void rtl8192_read_eeprom_info(struct net_device *dev)
>> u8 ICVer8192, ICVer8256;
>> u16 i, usValue, IC_Version;
>> u16 EEPROMId;
>> - u8 bMac_Tmp_Addr[6] = {0x00, 0xe0, 0x4c, 0x00, 0x00, 0x01};
>> + static const u8 bMac_Tmp_Addr[ETH_ALEN] __aligned(2) = {
>> + 0x00, 0xe0, 0x4c, 0x00, 0x00, 0x01
>> + };
>
> What's up with the whacky indenting?

It was proposal from Joe; perhaps breaking 80-column line would be even better in that case
(for sure will be once I remove __aligned)

Regards,
Mateusz