> Quoting Jason Gunthorpe <[EMAIL PROTECTED]>:
> Subject: Re: [openib-general] [PATCH] IB/core - ib_umad can cause address
> alignment fault on ia64
>
> On Thu, Jan 18, 2007 at 06:14:31PM +0200, Michael S. Tsirkin wrote:
>
> > So the issue is that we are casting char *data which has no
> > alignment guarantees to 64 bit number. We really must find a way to
> > force 64 bit alignment for struct ib_user_mad all over. Would not
> > something like the following simple trick work?
>
> > struct ib_user_mad_hdr {
> > .............
> > } __attribute__((aligned (8)));
>
> You might get a similar result if you change:
>
> struct ib_user_mad {
> struct ib_user_mad_hdr hdr;
> __u8 data[0];
> };
>
> To
>
> struct ib_user_mad {
> struct ib_user_mad_hdr hdr;
> __u64 data[0];
> };
>
> Which is more clear since it is the data[0] that has the alignment
> requirement not the ib_usr_mad_hdr..
Hmm. Good idea. Patch?
Need to audit the code from other cases of 'u8 data'
being cast or a struct with 64 bit field, BTW.
> Plus you only get the pad if you actually need it.
You mean, no pad if ib_user_mad_hdr is used separately?
--
MST
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