Re: [PATCH v2 1/1] IB/mlx4: Unaligned access in send_reply_to_slave

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

[-- Attachment #1: Type: text/plain, Size: 984 bytes --]

On Tue, May 17, 2016 at 01:16:38AM -0400, shamir.rabinovitch-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org wrote:
> From: Shamir Rabinovitch <shamir.rabinovitch-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> 
> The problem is that the function 'send_reply_to_slave' get the
> 'req_sa_mad' as pointer whose address can be unaligned to 8 bytes.
> In this case the compiler cannot know in advance what will be the
> alignment of the 'data' field.
> 
> Sowmini Varadhan pointed to this reply from Dave Miller that say
> that memcpy should not be used to solve alignment issues:
> https://lkml.org/lkml/2015/10/21/352
> 
> The reason why memcpy works here is because we memcpy someting that
> is bigger then 8 bytes and so the compiler cannot optimize this to
> 'ldx' instruction.
> 
> Signed-off-by: Shamir Rabinovitch <shamir.rabinovitch-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

The difference between this version and previous version is in the
title, am I right?

Thanks.

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]