#include <linux/rcupdate.h>
#include <linux/marker.h>
#include <linux/err.h>
+#include <linux/slab.h>
extern struct marker __start___markers[];
extern struct marker __stop___markers[];
char ptype;
/*
- * disabling preemption to make sure the teardown of the callbacks can
- * be done correctly when they are in modules and they insure RCU read
- * coherency.
+ * preempt_disable does two things : disabling preemption to make sure
+ * the teardown of the callbacks can be done correctly when they are in
+ * modules and they insure RCU read coherency.
*/
preempt_disable();
- ptype = ACCESS_ONCE(mdata->ptype);
+ ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
/* Must read the ptype before ptr. They are not data dependant,
* so we put an explicit smp_rmb() here. */
smp_rmb();
- func = ACCESS_ONCE(mdata->single.func);
+ func = mdata->single.func;
/* Must read the ptr before private data. They are not data
* dependant, so we put an explicit smp_rmb() here. */
smp_rmb();
* in the fast path, so put the explicit barrier here.
*/
smp_read_barrier_depends();
- multi = ACCESS_ONCE(mdata->multi);
+ multi = mdata->multi;
for (i = 0; multi[i].func; i++) {
va_start(args, fmt);
multi[i].func(multi[i].probe_private, call_private, fmt,
char ptype;
preempt_disable();
- ptype = ACCESS_ONCE(mdata->ptype);
+ ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
/* Must read the ptype before ptr. They are not data dependant,
* so we put an explicit smp_rmb() here. */
smp_rmb();
- func = ACCESS_ONCE(mdata->single.func);
+ func = mdata->single.func;
/* Must read the ptr before private data. They are not data
* dependant, so we put an explicit smp_rmb() here. */
smp_rmb();
* in the fast path, so put the explicit barrier here.
*/
smp_read_barrier_depends();
- multi = ACCESS_ONCE(mdata->multi);
+ multi = mdata->multi;
for (i = 0; multi[i].func; i++)
multi[i].func(multi[i].probe_private, call_private, fmt,
&args);
/*
* Disable a marker and its probe callback.
- * Note: only after a synchronize_sched() issued after setting elem->call to the
- * empty function insures that the original callback is not used anymore. This
- * insured by preemption disabling around the call site.
+ * Note: only waiting an RCU period after setting elem->call to the empty
+ * function insures that the original callback is not used anymore. This insured
+ * by preempt_disable around the call site.
*/
static void disable_marker(struct marker *elem)
{
elem->ptype = 0; /* single probe */
/*
* Leave the private data and id there, because removal is racy and
- * should be done only after a synchronize_sched(). These are never used
- * until the next initialization anyway.
+ * should be done only after an RCU period. These are never used until
+ * the next initialization anyway.
*/
}
/*
* Update probes, removing the faulty probes.
- * Issues a synchronize_sched() when no reference to the module passed
- * as parameter is found in the probes so the probe module can be
- * safely unloaded from now on.
*
* Internal callback only changed before the first probe is connected to it.
* Single probe private data can only be changed on 0 -> 1 and 2 -> 1
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);
end:
mutex_unlock(&markers_mutex);
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);
remove_marker(name); /* Ignore busy error message */
ret = 0;
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);
remove_marker(entry->name); /* Ignore busy error message */
end: