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Commit 28325df0 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Linus Torvalds
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markers: use rcu_barrier_sched() and call_rcu_sched() 



rcu_barrier_sched() and call_rcu_sched() were introduced in 2.6.26 for the
Markers.  Change the marker code to use them.

It can be seen as a fix since the marker code was using an ugly,
temporary, #ifdef hack to work around CONFIG_PREEMPT_RCU.

Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: default avatarPaul McKenney <paulmck@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 24879a8e

kernel/marker.c

+8 −17
Original line number Diff line number Diff line
@@ -441,7 +441,7 @@ static int remove_marker(const char *name) 
	hlist_del(&e->hlist);

	/* Make sure the call_rcu has been executed */

	if (e->rcu_pending)

		rcu_barrier();

		rcu_barrier_sched();

	kfree(e);

	return 0;

}
@@ -476,7 +476,7 @@ static int marker_set_format(struct marker_entry **entry, const char *format) 
	hlist_del(&(*entry)->hlist);

	/* Make sure the call_rcu has been executed */

	if ((*entry)->rcu_pending)

		rcu_barrier();

		rcu_barrier_sched();

	kfree(*entry);

	*entry = e;

	trace_mark(core_marker_format, "name %s format %s",
@@ -655,7 +655,7 @@ int marker_probe_register(const char *name, const char *format, 
	 * make sure it's executed now.

	 */

	if (entry->rcu_pending)

		rcu_barrier();

		rcu_barrier_sched();

	old = marker_entry_add_probe(entry, probe, probe_private);

	if (IS_ERR(old)) {

		ret = PTR_ERR(old);
@@ -670,10 +670,7 @@ int marker_probe_register(const char *name, const char *format, 
	entry->rcu_pending = 1;

	/* write rcu_pending before calling the RCU callback */

	smp_wmb();

#ifdef CONFIG_PREEMPT_RCU

	synchronize_sched();	/* Until we have the call_rcu_sched() */

#endif

	call_rcu(&entry->rcu, free_old_closure);

	call_rcu_sched(&entry->rcu, free_old_closure);

end:

	mutex_unlock(&markers_mutex);

	return ret;
@@ -704,7 +701,7 @@ int marker_probe_unregister(const char *name, 
	if (!entry)

		goto end;

	if (entry->rcu_pending)

		rcu_barrier();

		rcu_barrier_sched();

	old = marker_entry_remove_probe(entry, probe, probe_private);

	mutex_unlock(&markers_mutex);

	marker_update_probes();		/* may update entry */
@@ -716,10 +713,7 @@ int marker_probe_unregister(const char *name, 
	entry->rcu_pending = 1;

	/* write rcu_pending before calling the RCU callback */

	smp_wmb();

#ifdef CONFIG_PREEMPT_RCU

	synchronize_sched();	/* Until we have the call_rcu_sched() */

#endif

	call_rcu(&entry->rcu, free_old_closure);

	call_rcu_sched(&entry->rcu, free_old_closure);

	remove_marker(name);	/* Ignore busy error message */

	ret = 0;

end:
@@ -786,7 +780,7 @@ int marker_probe_unregister_private_data(marker_probe_func *probe, 
		goto end;

	}

	if (entry->rcu_pending)

		rcu_barrier();

		rcu_barrier_sched();

	old = marker_entry_remove_probe(entry, NULL, probe_private);

	mutex_unlock(&markers_mutex);

	marker_update_probes();		/* may update entry */
@@ -797,10 +791,7 @@ int marker_probe_unregister_private_data(marker_probe_func *probe, 
	entry->rcu_pending = 1;

	/* write rcu_pending before calling the RCU callback */

	smp_wmb();

#ifdef CONFIG_PREEMPT_RCU

	synchronize_sched();	/* Until we have the call_rcu_sched() */

#endif

	call_rcu(&entry->rcu, free_old_closure);

	call_rcu_sched(&entry->rcu, free_old_closure);

	remove_marker(entry->name);	/* Ignore busy error message */

end:

	mutex_unlock(&markers_mutex);