srcu: Introduce srcu_read_{un,}lock_notrace() (fd55a281) · Commits · 戴 / test

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@google.com Reported-by:

Joel Fernandes <joelaf@google.com> Intermittently-reported-by:

Steven Rostedt <rostedt@goodmis.org> Signed-off-by:

Paul E. McKenney <paulmck@linux.vnet.ibm.com>

include/linux/srcu.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -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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