X-Git-Url: http://git.liburcu.org/?p=userspace-rcu.git;a=blobdiff_plain;f=src%2Furcu-pointer.h;fp=src%2Furcu-pointer.h;h=dc1a0dac60718b15d1f8eb844b3feca315dd4068;hp=0000000000000000000000000000000000000000;hb=6893800a4d1cc14dff0395ddcd660a5138db183d;hpb=a59f39055b5ecb77b68cf78b9839aa9e8e4ec332

diff --git a/src/urcu-pointer.h b/src/urcu-pointer.h
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+++ b/src/urcu-pointer.h
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+#ifndef _URCU_POINTER_H
+#define _URCU_POINTER_H
+
+/*
+ * urcu-pointer.h
+ *
+ * Userspace RCU header. Operations on pointers.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * IBM's contributions to this file may be relicensed under LGPLv2 or later.
+ */
+
+#include <urcu/compiler.h>
+#include <urcu/arch.h>
+#include <urcu/uatomic.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)
+
+#include <urcu/static/urcu-pointer.h>
+
+/*
+ * rcu_dereference(ptr)
+ *
+ * Fetch a RCU-protected pointer. Typically used to copy the variable ptr to a
+ * local variable.
+ */
+#define rcu_dereference		_rcu_dereference
+
+/*
+ * type *rcu_cmpxchg_pointer(type **ptr, type *new, type *old)
+ * type *rcu_xchg_pointer(type **ptr, type *new)
+ * void rcu_set_pointer(type **ptr, type *new)
+ *
+ * RCU pointer updates.
+ * @ptr: address of the pointer to modify
+ * @new: new pointer value
+ * @old: old pointer value (expected)
+ *
+ * return: old pointer value
+ */
+#define rcu_cmpxchg_pointer	_rcu_cmpxchg_pointer
+#define rcu_xchg_pointer	_rcu_xchg_pointer
+#define rcu_set_pointer		_rcu_set_pointer
+
+#else /* !(defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)) */
+
+extern void *rcu_dereference_sym(void *p);
+#define rcu_dereference(p)						     \
+	__extension__							     \
+	({								     \
+		__typeof__(p) _________p1 =	URCU_FORCE_CAST(__typeof__(p), \
+			rcu_dereference_sym(URCU_FORCE_CAST(void *, p)));    \
+		(_________p1);						     \
+	})
+
+extern void *rcu_cmpxchg_pointer_sym(void **p, void *old, void *_new);
+#define rcu_cmpxchg_pointer(p, old, _new)				     \
+	__extension__							     \
+	({								     \
+		__typeof__(*(p)) _________pold = (old);			     \
+		__typeof__(*(p)) _________pnew = (_new);		     \
+		__typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
+			rcu_cmpxchg_pointer_sym(URCU_FORCE_CAST(void **, p), \
+						_________pold,		     \
+						_________pnew));	     \
+		(_________p1);						     \
+	})
+
+extern void *rcu_xchg_pointer_sym(void **p, void *v);
+#define rcu_xchg_pointer(p, v)						     \
+	__extension__							     \
+	({								     \
+		__typeof__(*(p)) _________pv = (v);		             \
+		__typeof__(*(p)) _________p1 = URCU_FORCE_CAST(__typeof__(*(p)), \
+			rcu_xchg_pointer_sym(URCU_FORCE_CAST(void **, p),    \
+					     _________pv));		     \
+		(_________p1);						     \
+	})
+
+/*
+ * Note: rcu_set_pointer_sym returns @v because we don't want to break
+ * the ABI. At the API level, rcu_set_pointer() now returns void. Use of
+ * the return value is therefore deprecated, and will cause a build
+ * error.
+ */
+extern void *rcu_set_pointer_sym(void **p, void *v);
+#define rcu_set_pointer(p, v)						     \
+	do {								     \
+		__typeof__(*(p)) _________pv = (v);		             \
+		(void) rcu_set_pointer_sym(URCU_FORCE_CAST(void **, p),	     \
+					    _________pv);		     \
+	} while (0)
+
+#endif /* !(defined(_LGPL_SOURCE) || defined(URCU_INLINE_SMALL_FUNCTIONS)) */
+
+/*
+ * void rcu_assign_pointer(type *ptr, type *new)
+ *
+ * Same as rcu_set_pointer, but takes the pointer to assign to rather than its
+ * address as first parameter. Provided for compatibility with the Linux kernel
+ * RCU semantic.
+ */
+#define rcu_assign_pointer(p, v)	rcu_set_pointer((&p), (v))
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _URCU_POINTER_H */