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SubjectRe: [PATCH 3/5] staging: rtl8188eu: use is_multicast_ether_addr in rtw_xmit.c
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On 8/9/18 7:51 PM, Joe Perches wrote:
> On Thu, 2018-08-09 at 19:42 +0200, Michael Straube wrote:
>> On 8/9/18 7:13 PM, Joe Perches wrote:
>>> On Thu, 2018-08-09 at 19:01 +0200, Michael Straube wrote:
>>>> Use is_multicast_ether_addr instead of custom IS_MCAST in
>>>> core/rtw_xmit.c.
>>>
>>> Have you verified that all accesses are __aligned(2) ?
>>>
>>> If so, please state that in the patch description.
>>>
>>>> diff --git a/drivers/staging/rtl8188eu/core/rtw_xmit.c b/drivers/staging/rtl8188eu/core/rtw_xmit.c
>>>
>>> []
>>>> @@ -460,10 +460,10 @@ static s32 update_attrib(struct adapter *padapter, struct sk_buff *pkt, struct p
>>>> if ((pattrib->ether_type == ETH_P_ARP) || (pattrib->ether_type == ETH_P_PAE) || (pattrib->dhcp_pkt == 1))
>>>> rtw_lps_ctrl_wk_cmd(padapter, LPS_CTRL_SPECIAL_PACKET, 1);
>>>>
>>>> - bmcast = IS_MCAST(pattrib->ra);
>>>> + mcast = is_multicast_ether_addr(pattrib->ra);
>>>
>>> i.e.: is pattrib->ra __aligned(2) ?
>>>
>>> etc...
>>>
>>
>> Hi Joe,
>>
>> I looked at the function comment for is_multicast_ether_addr in etherdevice.h.
>> There is not mentioned that __aligned(2) is required. If it is, I will check.
>>
>> So, is it required although it's not mentioned for is_multicast_ether_addr?
>
> Well, it wasn't required initially, but
>
> commit d54385ce68cd18ab002b46f61246ad197cec92de
> Author: Alexander Duyck <alexander.h.duyck@redhat.com>
> Date: Thu Apr 30 14:53:54 2015 -0700
>
> etherdev: Process is_multicast_ether_addr at same size as other operations
>
> This change makes it so that we process the address in
> is_multicast_ether_addr at the same size as the other calls. This allows
> us to avoid duplicate reads when used with other calls such as
> is_zero_ether_addr or eth_addr_copy. In addition I have added a 64 bit
> version of the function so in eth_type_trans we can process the destination
> address as a 64 bit value throughout.
>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
> changed it without adding a note in the kernel-doc.
>
> So this is likely appropriate to avoid unaligned access traps:
> ---
> include/linux/etherdevice.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
> index 572e11bb8696..0f7086b4836a 100644
> --- a/include/linux/etherdevice.h
> +++ b/include/linux/etherdevice.h
> @@ -115,6 +115,8 @@ static inline bool is_zero_ether_addr(const u8 *addr)
> *
> * Return true if the address is a multicast address.
> * By definition the broadcast address is also a multicast address.
> + *
> + * Please note: addr must be aligned to u16.
> */
> static inline bool is_multicast_ether_addr(const u8 *addr)
> {
>

Ok, then I will check and resend the series.
Thanks again.

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