sys/sys/serialize.h

   1 /*
   2  * Provides a fast serialization facility that will serialize across blocking
   3  * conditions.  This facility is very similar to a lock but much faster for
   4  * the common case.  It utilizes the atomic_intr_*() functions to acquire
   5  * and release the serializer and token functions to block.
   6  *
   7  * This API is designed to be used whenever low level serialization is
   8  * required.  Unlike tokens this serialization is not safe from deadlocks
   9  * nor is it recursive, and care must be taken when using it.
  10  *
  11  * $DragonFly: src/sys/sys/serialize.h,v 1.4 2006/08/26 17:43:54 joerg Exp $
  12  */
  13
  14 #ifndef _SYS_SERIALIZE_H_
  15 #define _SYS_SERIALIZE_H_
  16
  17 #ifndef _MACHINE_STDINT_H_
  18 #include <machine/stdint.h>
  19 #endif
  20
  21 struct thread;
  22
  23 struct lwkt_serialize {
  24     __atomic_intr_t     interlock;
  25     struct thread       *last_td;
  26 };
  27
  28 /*
  29  * Note that last_td is only maintained when INVARIANTS is turned on,
  30  * so this check is only useful as part of a [K]KASSERT.
  31  */
  32 #define ASSERT_SERIALIZED(ss)   KKASSERT((ss)->last_td == curthread)
  33
  34 typedef struct lwkt_serialize *lwkt_serialize_t;
  35
  36 void lwkt_serialize_init(lwkt_serialize_t);
  37 void lwkt_serialize_enter(lwkt_serialize_t);
  38 int lwkt_serialize_try(lwkt_serialize_t);
  39 void lwkt_serialize_exit(lwkt_serialize_t);
  40 void lwkt_serialize_handler_disable(lwkt_serialize_t);
  41 void lwkt_serialize_handler_enable(lwkt_serialize_t);
  42 void lwkt_serialize_handler_call(lwkt_serialize_t, void (*)(void *, void *), void *, void *);
  43 int lwkt_serialize_handler_try(lwkt_serialize_t, void (*)(void *, void *), void *, void *);
  44
  45 #endif