X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu.h;h=0b0d232311a58666c8b41a9c3162b4efb8caaed4;hp=b6b5c7b039e359225d947afb91a29a2f25ba6a3c;hb=121a5d44c8cc7197116df73854cb94c6cfbad0b0;hpb=c265818b951224bcde407b1efa14f9daf44949b3

diff --git a/urcu.h b/urcu.h
index b6b5c7b..0b0d232 100644
--- a/urcu.h
+++ b/urcu.h
@@ -8,104 +8,71 @@
  *
  * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  *
- * Credits for Paul e. McKenney <paulmck@linux.vnet.ibm.com>
+ * Credits for Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  * for inspiration coming from the Linux kernel RCU and rcu-preempt.
  *
- * The barrier, mb, rmb, wmb, atomic_inc, smp_read_barrier_depends, ACCESS_ONCE
- * and rcu_dereference primitives come from the Linux kernel.
+ * LGPL-compatible code should include this header with :
  *
- * Distributed under GPLv2
+ * #define _LGPL_SOURCE
+ * #include <urcu.h>
+ *
+ * Distributed under LGPLv2.1
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
  */
 
-/* The "volatile" is due to gcc bugs */
-#define barrier() __asm__ __volatile__("": : :"memory")
+#include <stdlib.h>
+#include <pthread.h>
 
-/* x86 32/64 specific */
-#define mb()    asm volatile("mfence":::"memory")
-#define rmb()   asm volatile("lfence":::"memory")
-#define wmb()   asm volatile("sfence" ::: "memory")
+#ifdef _LGPL_SOURCE
 
-static inline void atomic_inc(int *v)
-{
-	asm volatile("lock; incl %0"
-		     : "+m" (*v));
-}
-
-/* Nop everywhere except on alpha. */
-#define smp_read_barrier_depends()
+#include <urcu-static.h>
 
 /*
- * Prevent the compiler from merging or refetching accesses.  The compiler
- * is also forbidden from reordering successive instances of ACCESS_ONCE(),
- * but only when the compiler is aware of some particular ordering.  One way
- * to make the compiler aware of ordering is to put the two invocations of
- * ACCESS_ONCE() in different C statements.
- *
- * This macro does absolutely -nothing- to prevent the CPU from reordering,
- * merging, or refetching absolutely anything at any time.  Its main intended
- * use is to mediate communication between process-level code and irq/NMI
- * handlers, all running on the same CPU.
+ * Mappings for static use of the userspace RCU library.
+ * Should only be used in LGPL-compatible code.
  */
-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
 
-/**
- * rcu_dereference - fetch an RCU-protected pointer in an
- * RCU read-side critical section.  This pointer may later
- * be safely dereferenced.
- *
- * Inserts memory barriers on architectures that require them
- * (currently only the Alpha), and, more importantly, documents
- * exactly which pointers are protected by RCU.
+#define rcu_dereference		_rcu_dereference
+#define rcu_read_lock		_rcu_read_lock
+#define rcu_read_unlock		_rcu_read_unlock
+
+#define rcu_assign_pointer	_rcu_assign_pointer
+#define rcu_xchg_pointer	_rcu_xchg_pointer
+#define rcu_publish_content	_rcu_publish_content
+
+#else /* !_LGPL_SOURCE */
+
+/*
+ * library wrappers to be used by non-LGPL compatible source code.
  */
 
-#define rcu_dereference(p)     ({ \
-				typeof(p) _________p1 = ACCESS_ONCE(p); \
-				smp_read_barrier_depends(); \
-				(_________p1); \
-				})
+extern void rcu_read_lock(void);
+extern void rcu_read_unlock(void);
 
-#define SIGURCU SIGUSR1
+extern void *rcu_dereference(void *p);
 
-/* Global quiescent period parity */
-extern int urcu_qparity;
+extern void *rcu_assign_pointer_sym(void **p, void *v);
 
-extern int __thread urcu_active_readers[2];
+#define rcu_assign_pointer(p, v)			\
+	rcu_assign_pointer_sym((void **)(p), (v))
 
-static inline int get_urcu_qparity(void)
-{
-	return urcu_qparity;
-}
+extern void *rcu_xchg_pointer_sym(void **p, void *v);
+#define rcu_xchg_pointer(p, v)				\
+	rcu_xchg_pointer_sym((void **)(p), (v))
 
-/*
- * urcu_parity should be declared on the caller's stack.
- */
-static inline void rcu_read_lock(int *urcu_parity)
-{
-	*urcu_parity = get_urcu_qparity();
-	urcu_active_readers[*urcu_parity]++;
-	/*
-	 * Increment active readers count before accessing the pointer.
-	 * See force_mb_all_threads().
-	 */
-	barrier();
-}
-
-static inline void rcu_read_unlock(int *urcu_parity)
-{
-	barrier();
-	/*
-	 * Finish using rcu before decrementing the pointer.
-	 * See force_mb_all_threads().
-	 */
-	urcu_active_readers[*urcu_parity]--;
-}
-
-extern void *urcu_publish_content(void **ptr, void *new);
+extern void *rcu_publish_content_sym(void **p, void *v);
+#define rcu_publish_content(p, v)			\
+	rcu_publish_content_sym((void **)(p), (v))
+
+#endif /* !_LGPL_SOURCE */
+
+extern void synchronize_rcu(void);
 
 /*
  * Reader thread registration.
  */
-extern void urcu_register_thread(void);
-extern void urcu_unregister_thread(void);
+extern void rcu_register_thread(void);
+extern void rcu_unregister_thread(void);
 
 #endif /* _URCU_H */