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/**

 * raw_write_seqcount_barrier - do a seq write barrier

 * @s: pointer to seqcount_t

 *

 * This can be used to provide an ordering guarantee instead of the

 * usual consistency guarantee. It is one wmb cheaper, because we can

 * collapse the two back-to-back wmb()s.

 *

 *      seqcount_t seq;

 *      bool X = true, Y = false;

 *

 *      void read(void)

 *      {

 *              bool x, y;

 *

 *              do {

 *                      int s = read_seqcount_begin(&seq);

 *

 *                      x = X; y = Y;

 *

 *              } while (read_seqcount_retry(&seq, s));

 *

 *              BUG_ON(!x && !y);

 *      }

 *

 *      void write(void)

 *      {

 *              Y = true;

 *

 *              raw_write_seqcount_barrier(seq);

 *

 *              X = false;

 *      }

 */

static inline void raw_write_seqcount_barrier(seqcount_t *s)

{

	s->sequence++;

	smp_wmb();

	s->sequence++;

}

static inline int raw_read_seqcount_latch(seqcount_t *s)

{

	return lockless_dereference(s->sequence);

}