svn commit: r361550 - head/sys/compat/linuxkpi/common/include/linux

[Emmanuel Vadot]

Author: manu
Date: Wed May 27 10:01:30 2020
New Revision: 361550
URL: https://svnweb.freebsd.org/changeset/base/361550

Log:
  linuxkpi: Add rcu_swap_protected
  
  This macros swap an rcu pointer with a normal pointer.
  The condition only seems to be used for debug/warning under linux, ignore
  for now.
  
  Sponsored-by: The FreeBSD Foundation
  Reviewed by:	hselasky
  Differential Revision:	https://reviews.freebsd.org/D24954

Modified:
  head/sys/compat/linuxkpi/common/include/linux/rcupdate.h

Modified: head/sys/compat/linuxkpi/common/include/linux/rcupdate.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/linux/rcupdate.h	Wed May 27 09:31:50 2020	(r361549)
+++ head/sys/compat/linuxkpi/common/include/linux/rcupdate.h	Wed May 27 10:01:30 2020	(r361550)
@@ -97,6 +97,12 @@
 	    (uintptr_t)(v));					\
 } while (0)
 
+#define	rcu_swap_protected(rcu, ptr, c) do {			\
+	typeof(ptr) p = rcu_dereference_protected(rcu, c);	\
+	rcu_assign_pointer(rcu, ptr);				\
+	(ptr) = p;						\
+} while (0)
+
 /* prototypes */
 
 extern void linux_call_rcu(unsigned type, struct rcu_head *ptr, rcu_callback_t func);