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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-04-29 01:39:09 +0400
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-08-20 04:17:59 +0400
commitca5ecddfa8fcbd948c95530e7e817cee9fb43a3d (patch)
tree0ad1c320c2e6612a9a230a58d8588850701c048c /include/linux/compiler.h
parentd34a16661ed0fed433c9469d7cfa3ca4d30ca42e (diff)
downloadlinux-ca5ecddfa8fcbd948c95530e7e817cee9fb43a3d.tar.xz
rcu: define __rcu address space modifier for sparse
This commit provides definitions for the __rcu annotation defined earlier. This annotation permits sparse to check for correct use of RCU-protected pointers. If a pointer that is annotated with __rcu is accessed directly (as opposed to via rcu_dereference(), rcu_assign_pointer(), or one of their variants), sparse can be made to complain. To enable such complaints, use the new default-disabled CONFIG_SPARSE_RCU_POINTER kernel configuration option. Please note that these sparse complaints are intended to be a debugging aid, -not- a code-style-enforcement mechanism. There are special rcu_dereference_protected() and rcu_access_pointer() accessors for use when RCU read-side protection is not required, for example, when no other CPU has access to the data structure in question or while the current CPU hold the update-side lock. This patch also updates a number of docbook comments that were showing their age. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Christopher Li <sparse@chrisli.org> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'include/linux/compiler.h')
-rw-r--r--include/linux/compiler.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index c1a62c56a660..320d6c94ff84 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -16,7 +16,11 @@
# define __release(x) __context__(x,-1)
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
# define __percpu __attribute__((noderef, address_space(3)))
+#ifdef CONFIG_SPARSE_RCU_POINTER
+# define __rcu __attribute__((noderef, address_space(4)))
+#else
# define __rcu
+#endif
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
#else