[parisc-linux] gcc-3.[02] alignment problem

[Richard Henderson]

On Tue, Jul 16, 2002 at 10:22:55AM -0700, Randolph Chung wrote:
>         __u32   tcpdiag_cookie[2]; 
> #define TCPDIAG_NOCOOKIE (~0U)
> };
> 
> the code goes on to do:
>         *((struct sock **)&r->id.tcpdiag_cookie) = sk;
> and
>             sk != *((struct sock **)&req->id.tcpdiag_cookie[0]))

This is absolutely awful.

> the "vomit grade hack" alan mentioned in another post is that in our
> tree, we have:
> 
> struct tcpdiag_sockid
> {
>         __u16   tcpdiag_sport;
>         __u16   tcpdiag_dport;
>         __u32   tcpdiag_src[4];
>         __u32   tcpdiag_dst[4];
>         __u32   tcpdiag_if;
> #if defined (__hppa__) && defined (__LP64__)
>         char * parisc_hack_to_align_tcpdiag_cookie;
> #endif
>         __u32   tcpdiag_cookie[2];

An only marginally better fix is

	__u32 tcpdiag_cookie[2] __attribute__((aligned(sizeof(void*))));

Note that this should be unconditional so that the other
64-bit ports don't take an alignment trap here too.

A much nicer fix would be to, gasp, use a union.



r~