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-rw-r--r--kernel/marker.c36
1 files changed, 24 insertions, 12 deletions
diff --git a/kernel/marker.c b/kernel/marker.c
index 7d1faec..e9c6b2b 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -62,7 +62,7 @@ struct marker_entry {
int refcount; /* Number of times armed. 0 if disarmed. */
struct rcu_head rcu;
void *oldptr;
- unsigned char rcu_pending:1;
+ int rcu_pending;
unsigned char ptype:1;
char name[0]; /* Contains name'\0'format'\0' */
};
@@ -103,11 +103,11 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
char ptype;
/*
- * 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.
+ * rcu_read_lock_sched 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();
+ rcu_read_lock_sched();
ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
@@ -145,7 +145,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private, ...)
va_end(args);
}
}
- preempt_enable();
+ rcu_read_unlock_sched();
}
EXPORT_SYMBOL_GPL(marker_probe_cb);
@@ -162,7 +162,7 @@ void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
va_list args; /* not initialized */
char ptype;
- preempt_disable();
+ rcu_read_lock_sched();
ptype = mdata->ptype;
if (likely(!ptype)) {
marker_probe_func *func;
@@ -195,7 +195,7 @@ void marker_probe_cb_noarg(const struct marker *mdata, void *call_private, ...)
multi[i].func(multi[i].probe_private, call_private,
mdata->format, &args);
}
- preempt_enable();
+ rcu_read_unlock_sched();
}
EXPORT_SYMBOL_GPL(marker_probe_cb_noarg);
@@ -560,7 +560,7 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
* Disable a marker and its probe callback.
* 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.
+ * by rcu_read_lock_sched around the call site.
*/
static void disable_marker(struct marker *elem)
{
@@ -653,11 +653,17 @@ int marker_probe_register(const char *name, const char *format,
entry = get_marker(name);
if (!entry) {
entry = add_marker(name, format);
- if (IS_ERR(entry)) {
+ if (IS_ERR(entry))
ret = PTR_ERR(entry);
- goto end;
- }
+ } else if (format) {
+ if (!entry->format)
+ ret = marker_set_format(&entry, format);
+ else if (strcmp(entry->format, format))
+ ret = -EPERM;
}
+ if (ret)
+ goto end;
+
/*
* If we detect that a call_rcu is pending for this marker,
* make sure it's executed now.
@@ -674,6 +680,8 @@ int marker_probe_register(const char *name, const char *format,
mutex_lock(&markers_mutex);
entry = get_marker(name);
WARN_ON(!entry);
+ if (entry->rcu_pending)
+ rcu_barrier_sched();
entry->oldptr = old;
entry->rcu_pending = 1;
/* write rcu_pending before calling the RCU callback */
@@ -717,6 +725,8 @@ int marker_probe_unregister(const char *name,
entry = get_marker(name);
if (!entry)
goto end;
+ if (entry->rcu_pending)
+ rcu_barrier_sched();
entry->oldptr = old;
entry->rcu_pending = 1;
/* write rcu_pending before calling the RCU callback */
@@ -795,6 +805,8 @@ int marker_probe_unregister_private_data(marker_probe_func *probe,
mutex_lock(&markers_mutex);
entry = get_marker_from_private_data(probe, probe_private);
WARN_ON(!entry);
+ if (entry->rcu_pending)
+ rcu_barrier_sched();
entry->oldptr = old;
entry->rcu_pending = 1;
/* write rcu_pending before calling the RCU callback */
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