sc92031: remove bogus unlikely()

[pandora-kernel.git] / kernel / marker.c

diff --git a/kernel/marker.c b/kernel/marker.c
index 48a4ea5..b5a9fe1 100644 (file)
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -23,12 +23,13 @@
 #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[];
 
 /* Set to 1 to enable marker debug output */
-const int marker_debug;
+static const int marker_debug;
 
 /*
  * markers_mutex nests inside module_mutex. Markers mutex protects the builtin
@@ -104,18 +105,18 @@ void marker_probe_cb(const struct marker *mdata, void *call_private,
        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();
@@ -133,7 +134,7 @@ void marker_probe_cb(const struct marker *mdata, void *call_private,
                 * 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,
@@ -161,13 +162,13 @@ void marker_probe_cb_noarg(const struct marker *mdata,
        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();
@@ -183,7 +184,7 @@ void marker_probe_cb_noarg(const struct marker *mdata,
                 * 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);
@@ -551,9 +552,9 @@ static int set_marker(struct marker_entry **entry, struct marker *elem,
 
 /*
  * 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)
 {
@@ -565,8 +566,8 @@ 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.
         */
 }
 
@@ -601,9 +602,6 @@ void marker_update_probe_range(struct marker *begin,
 
 /*
  * 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
@@ -674,6 +672,9 @@ 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);
 end:
        mutex_unlock(&markers_mutex);
@@ -717,6 +718,9 @@ 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);
        remove_marker(name);    /* Ignore busy error message */
        ret = 0;
@@ -795,6 +799,9 @@ 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);
        remove_marker(entry->name);     /* Ignore busy error message */
 end: