Philippe Gerum wrote:
> We should indeed postpone this just in case the upper layer indexes the extra
> state on the minor value. We can also simplify a few things doing so.
>
> --- ksrc/nucleus/pipe.c (revision 4565)
> +++ ksrc/nucleus/pipe.c (working copy)
> @@ -77,11 +77,9 @@
>
> static inline void xnpipe_minor_free(int minor)
> {
> - if (minor < 0 || minor >= XNPIPE_NDEVS)
> - return;
> -
> - __clrbits(xnpipe_bitmap[minor / BITS_PER_LONG],
> - 1UL << (minor % BITS_PER_LONG));
> + /* May be called with nklock free. */
> + clrbits(xnpipe_bitmap[minor / BITS_PER_LONG],
> + 1UL << (minor % BITS_PER_LONG));
Bad news: This doesn't fly as is. All modifying operations on
xnpipe_bitmap must be atomic and xnpipe_bitmap has to be
xnarch_atomic_t. But then find_first_zero_bit breaks. Is there some
version for atomic arrays? I guess we have to open-code this, at least
down to word-level...
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
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