Re: [PATCH 06/19] dlm: align midcomms message buffer

[Fabio M. Di Nitto]

On Sat, 26 Jan 2008, Andrew Morton wrote:

> > On Thu, 24 Jan 2008 10:50:29 -0600 David Teigland <teigland@xxxxxxxxxx> wrote:
> > From: Fabio M. Di Nitto <fabbione@xxxxxxxxxx>
> >
> > gcc does not guarantee that a static buffer is 64bit aligned. This change
> > allows sparc64 to work.
>
> This buffer is not static: changelog needs fixing: s/static/auto/
>
> > ---
> >  fs/dlm/midcomms.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/fs/dlm/midcomms.c b/fs/dlm/midcomms.c
> > index f8c69dd..da653b5 100644
> > --- a/fs/dlm/midcomms.c
> > +++ b/fs/dlm/midcomms.c
> > @@ -58,7 +58,7 @@ static void copy_from_cb(void *dst, const void *base, unsigned offset,
> >  int dlm_process_incoming_buffer(int nodeid, const void *base,
> >  				unsigned offset, unsigned len, unsigned limit)
> >  {
> > -	unsigned char __tmp[DLM_INBUF_LEN];
> > +	unsigned char __tmp[DLM_INBUF_LEN] __attribute__((aligned(64)));
> >  	struct dlm_header *msg = (struct dlm_header *) __tmp;
> >  	int ret = 0;
> >  	int err = 0;
>
> Why does DLM require that this thing be 64-bit aligned?
>
> It all looks rather ugly.  Can't this stuff be implemeted within the C type
> system somehow?

how about this one: