Re: [PATCH rdma-next] RDMA: Use __packed annotation instead of __attribute__ ((packed))

[Gal Pressman <galpress@xxxxxxxxxx>]

On 25-Feb-19 16:54, Bart Van Assche wrote:
> On 2/24/19 10:52 PM, Leon Romanovsky wrote:
>> diff --git a/drivers/infiniband/core/cm_msgs.h
>> b/drivers/infiniband/core/cm_msgs.h
>> index 476d4309576d..3d16d614aff6 100644
>> --- a/drivers/infiniband/core/cm_msgs.h
>> +++ b/drivers/infiniband/core/cm_msgs.h
>> @@ -98,7 +98,7 @@ struct cm_req_msg {
>>
>>       u32 private_data[IB_CM_REQ_PRIVATE_DATA_SIZE / sizeof(u32)];
>>
>> -} __attribute__ ((packed));
>> +} __packed;
> 
> Hi Leon,
> 
> A previous RDMA maintainer once wrote a blog in which he explained why it is
> better to apply the __packed attribute only to data members that need it instead
> of to data structures. The reason is that applying __packed to data structures
> does not allow compilers to generate optimal code for architectures that cannot
> perform non-aligned multi-byte reads efficiently. Does that concern apply to the
> data structures modified by this patch?

Hi Bart,
By any chance do you have a link to this post?

Thanks!