Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fd55a281 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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@google.com



Reported-by: default avatarJoel Fernandes <joelaf@google.com>
Intermittently-reported-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 5ab07a8d

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

 *