Re: [patch] s390: fadvise hint values.

[Christoph Hellwig <hch@infradead.org>]

On Tue, Jul 12, 2005 at 01:52:19PM +0200, Martin Schwidefsky wrote:
> Hi Andrew,
> an ugly one. The fadvise hint values for POSIX_FADV_DONTNEED and
> POSIX_FADV_NOREUSE in the kernel and the glibc differ for s390-64
> (and worse the values for s390-31 and s390-64 differ as well ..).
> The glibc always had 6 and 7 instead of 4 and 5 for these two values
> for s390-64. My first reaction was to correct the values in the
> glibc headers but as Ulrich Drepper pointed out that has some
> unwanted consequences:
> 1) the applications build against the wrong values will get -EINVAL
>    and the advice gets ignored, and
> 2) if the values 6 and 7 are ever used for some new advice then
>    these applications might show erratic behaviour.
> I can't say which and how many applications use fadvise so it might
> be a better idea to fix this in the kernel.
> 
> Patch is attached, what do you think ?

I'd rather fix the kernel and do some symbol versioning magic in
glibc.  After all it's their stupidity that caused all these problems.