Commit-ID: fd55a281adf6c9b9723d369203fdd92e5ea62a09
Gitweb: https://git.kernel.org/tip/fd55a281adf6c9b9723d369203fdd92e5ea62a09
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 27 Apr 2018 10:06:03 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon, 25 Jun 2018 11:26:24 -0700
srcu: Introduce srcu_read_{un,}lock_notrace()
Joel Fernandes is using SRCU to protect from-idle tracepoints, which
requires notrace variants of srcu_read_lock() and srcu_read_unlock()
in order to avoid problems with tracepoints in lockdep. This commit
therefore adds srcu_read_lock_notrace() and srcu_read_unlock_notrace().
[1] http://lkml.kernel.org/r/20180427042656.190746-1-joelaf@xxxxxxxxxx
Reported-by: Joel Fernandes <joelaf@xxxxxxxxxx>
Intermittently-reported-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/srcu.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 91494d7e8e41..3e72a291c401 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -195,6 +195,16 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
return retval;
}
+/* Used by tracing, cannot be traced and cannot invoke lockdep. */
+static inline notrace int
+srcu_read_lock_notrace(struct srcu_struct *sp) __acquires(sp)
+{
+ int retval;
+
+ retval = __srcu_read_lock(sp);
+ return retval;
+}
+
/**
* srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
* @sp: srcu_struct in which to unregister the old reader.
@@ -209,6 +219,13 @@ static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
__srcu_read_unlock(sp, idx);
}
+/* Used by tracing, cannot be traced and cannot call lockdep. */
+static inline notrace void
+srcu_read_unlock_notrace(struct srcu_struct *sp, int idx) __releases(sp)
+{
+ __srcu_read_unlock(sp, idx);
+}
+
/**
* smp_mb__after_srcu_read_unlock - ensure full ordering after srcu_read_unlock
*
--
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