Re: [Xenomai-core] Pending patches

[Jan Kiszka <jan.kiszka@domain.hid>]

Jan Kiszka wrote:
> 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...

Ok, xnpipe_bitmap can remain ulong but
a) xnpipe_minor_alloc must use setbits and
b) for some reasons clrbits in xnpipe_minor_free does not build on my 64
bit host. Maybe compiler issue. Investigating...

Jan

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