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Code Issues Releases Wiki Activity

srcu: Introduce srcu_read_{un,}lock_notrace()

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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>
This commit is contained in:
Paul E. McKenney 2018-04-27 10:06:03 -07:00
parent 5ab07a8df4
commit fd55a281ad
1 changed files with 17 additions and 0 deletions
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17
include/linux/srcu.h
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@ -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
*