Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[karo-tx-linux.git] / kernel / trace / trace_output.c

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 425725c1622dbc971b6d9510ac1528047cd28ae3..7938f3ae93e3dbe9d898e037c47027c4908a8d94 100644 (file)
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -14,7 +14,7 @@
 /* must be a power of 2 */
 #define EVENT_HASHSIZE 128
 
-static DECLARE_RWSEM(trace_event_mutex);
+DECLARE_RWSEM(trace_event_mutex);
 
 DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq);
 EXPORT_PER_CPU_SYMBOL(ftrace_event_seq);
@@ -100,6 +100,38 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 }
 EXPORT_SYMBOL_GPL(trace_seq_printf);
 
+/**
+ * trace_seq_vprintf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formating of a trace
+ * trace_seq_printf is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ */
+int
+trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
+{
+       int len = (PAGE_SIZE - 1) - s->len;
+       int ret;
+
+       if (!len)
+               return 0;
+
+       ret = vsnprintf(s->buffer + s->len, len, fmt, args);
+
+       /* If we can't write it all, don't bother writing anything */
+       if (ret >= len)
+               return 0;
+
+       s->len += ret;
+
+       return len;
+}
+EXPORT_SYMBOL_GPL(trace_seq_vprintf);
+
 int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary)
 {
        int len = (PAGE_SIZE - 1) - s->len;
@@ -670,6 +702,16 @@ int register_ftrace_event(struct trace_event *event)
 }
 EXPORT_SYMBOL_GPL(register_ftrace_event);
 
+/*
+ * Used by module code with the trace_event_mutex held for write.
+ */
+int __unregister_ftrace_event(struct trace_event *event)
+{
+       hlist_del(&event->node);
+       list_del(&event->list);
+       return 0;
+}
+
 /**
  * unregister_ftrace_event - remove a no longer used event
  * @event: the event to remove
@@ -677,8 +719,7 @@ EXPORT_SYMBOL_GPL(register_ftrace_event);
 int unregister_ftrace_event(struct trace_event *event)
 {
        down_write(&trace_event_mutex);
-       hlist_del(&event->node);
-       list_del(&event->list);
+       __unregister_ftrace_event(event);
        up_write(&trace_event_mutex);
 
        return 0;