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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-04-28 14:39:09 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-08-19 17:17:59 -0700
commitca5ecddfa8fcbd948c95530e7e817cee9fb43a3d (patch)
tree0ad1c320c2e6612a9a230a58d8588850701c048c /lib/Kconfig.debug
parentd34a16661ed0fed433c9469d7cfa3ca4d30ca42e (diff)
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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 'lib/Kconfig.debug')
-rw-r--r--lib/Kconfig.debug13
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1b4afd2e6ca..12465f2ef76 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -539,6 +539,19 @@ config PROVE_RCU_REPEATEDLY
disabling, allowing multiple RCU-lockdep warnings to be printed
on a single reboot.
+config SPARSE_RCU_POINTER
+ bool "RCU debugging: sparse-based checks for pointer usage"
+ default n
+ help
+ This feature enables the __rcu sparse annotation for
+ RCU-protected pointers. This annotation will cause sparse
+ to flag any non-RCU used of annotated pointers. This can be
+ helpful when debugging RCU usage. Please note that this feature
+ is not intended to enforce code cleanliness; it is instead merely
+ a debugging aid.
+
+ Say Y to make sparse flag questionable use of RCU-protected pointers
+
Say N if you are unsure.
config LOCKDEP