Re: [PATCH] remove BKL from ext2's readdir

Andi Kleen (ak@muc.de)
Sat, 15 Mar 2003 22:55:11 +0100


Andrew Morton <akpm@digeo.com> writes:

> foo_readdir()
> {
> loff_t pos = file->f_pos;
>
> ....
> <code which doesn't touch file->f_pos, but which modifies pos>
> ...
>
> file->f_pos = pos;
> }

At least for alpha this will require an rmb_depends() between the read
and the write. Probably on x86 an rmb() wouldn't hurt neither.

Otherwise there is no guarantee other CPUs see that intended memory
modification order

-Andi
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