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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-04-28 14:39:09 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2010-08-19 17:17:59 -0700 |
| commit | ca5ecddfa8fcbd948c95530e7e817cee9fb43a3d (patch) | |
| tree | 0ad1c320c2e6612a9a230a58d8588850701c048c /lib/Kconfig.debug | |
| parent | d34a16661ed0fed433c9469d7cfa3ca4d30ca42e (diff) | |
| download | lwn-ca5ecddfa8fcbd948c95530e7e817cee9fb43a3d.tar.gz lwn-ca5ecddfa8fcbd948c95530e7e817cee9fb43a3d.zip | |
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.debug | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 1b4afd2e6ca0..12465f2ef766 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 |