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authorJoel Fernandes (Google) <joel@joelfernandes.org>2018-06-28 11:21:44 -0700
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-07-26 10:50:16 -0400
commit0b764a6e4e19dc254caca636002eaa47b1d0b0af (patch)
tree53ef602e29f6987ed13e629f2dcee617566adf5b /include/linux/srcu.h
parent1f45a4db3657c5ecafb7d3331536c987e6d18311 (diff)
srcu: Add notrace variant of srcu_dereference
In the last patch in this series, we are making lockdep register hooks onto the irq_{disable,enable} tracepoints. These tracepoints use the _rcuidle tracepoint variant. In this series we switch the _rcuidle tracepoint callers to use SRCU instead of sched-RCU. Inorder to dereference the pointer to the probe functions, we could call srcu_dereference, however this API will call back into lockdep to check if the lock is held *before* the lockdep probe hooks have a chance to run and annotate the IRQ enabled/disabled state. For this reason we need a notrace variant of srcu_dereference since otherwise we get lockdep splats. This patch adds the needed srcu_dereference_notrace variant. Link: http://lkml.kernel.org/r/20180628182149.226164-3-joel@joelfernandes.org Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/srcu.h')
-rw-r--r--include/linux/srcu.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 3e72a291c401..67135d4a8a30 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -170,6 +170,11 @@ static inline int srcu_read_lock_held(const struct srcu_struct *sp)
#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
/**
+ * srcu_dereference_notrace - no tracing and no lockdep calls from here
+ */
+#define srcu_dereference_notrace(p, sp) srcu_dereference_check((p), (sp), 1)
+
+/**
* srcu_read_lock - register a new reader for an SRCU-protected structure.
* @sp: srcu_struct in which to register the new reader.
*