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

From: Andrew Morton
Date: Sun Jan 27 2008 - 01:01:20 EST


> 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?
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