13  * - Sequence counters with associated locks, (C) 2020 Linutronix GmbH
27  * The seqlock seqcount_t interface does not prescribe a precise sequence of
42  * Sequence counters (seqcount_t)
56  * locking primitives, use a sequence counter with associated lock
59  * If it's desired to automatically handle the sequence counter writer
66 	unsigned sequence;  member
79 	s->sequence = 0;  in __seqcount_init()
118 #define SEQCNT_ZERO(name) { .sequence = 0, SEQCOUNT_DEP_MAP_INIT(name) }
121  * Sequence counters with associated locks (seqcount_LOCKNAME_t)
123  * A sequence counter which associates the lock used for writer
158  * typedef seqcount_LOCKNAME_t - sequence counter with LOCKNAME associated
159  * @seqcount:	The real sequence counter
162  * A plain sequence counter with external writer synchronization by
163  * LOCKNAME @lock. The lock is associated to the sequence counter in the
215 	unsigned seq = READ_ONCE(s->seqcount.sequence);			\
225 		 * Re-read the sequence counter since the (possibly	\
228 		seq = READ_ONCE(s->seqcount.sequence);			\
261 	return READ_ONCE(s->sequence);  in __seqprop_sequence()
311 #define __seqcount_sequence(s)		__seqprop(s, sequence)
372  * masking the sequence counter LSB. Calling code is responsible for
433 	return unlikely(READ_ONCE(s->sequence) != start);  in __read_seqcount_t_retry()
471 	s->sequence++;  in raw_write_seqcount_t_begin()
490 	s->sequence++;  in raw_write_seqcount_t_end()
611 	s->sequence++;  in raw_write_seqcount_t_barrier()
613 	s->sequence++;  in raw_write_seqcount_t_barrier()
632 	s->sequence+=2;  in write_seqcount_t_invalidate()
637  * Latch sequence counters (seqcount_latch_t)
639  * A sequence counter variant where the counter even/odd value is used to
674  * Return: sequence counter raw value. Use the lowest bit as an index for
684 	return READ_ONCE(s->seqcount.sequence);  in raw_read_seqcount_latch()
731  *		latch->seq.sequence++;
737  *		latch->seq.sequence++;
773  *	to miss an entire modification sequence, once it resumes it might
783 	smp_wmb();	/* prior stores before incrementing "sequence" */  in raw_write_seqcount_latch()
784 	s->seqcount.sequence++;  in raw_write_seqcount_latch()
785 	smp_wmb();      /* increment "sequence" before following stores */  in raw_write_seqcount_latch()
791  * Sequence counters with an embedded spinlock for writer serialization
1002  * locking readers, but it does not update the embedded sequence number.
1133  * Return: the encountered sequence counter value, through the @seq
1150  * @seq: sequence count, from read_seqbegin_or_lock()
1190  *   2. The encountered sequence counter value, returned through @seq