tracing: Add trace_export support for trace_marker

Add the support to route trace_marker buffer to other destination
via trace_export.

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Link: https://lore.kernel.org/r/20201005071319.78508-5-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/trace.h b/include/linux/trace.h
index 86033d2..886a4ff 100644 (file)
--- a/include/linux/trace.h
+++ b/include/linux/trace.h
@@ -6,6 +6,7 @@
 
 #define TRACE_EXPORT_FUNCTION  BIT(0)
 #define TRACE_EXPORT_EVENT     BIT(1)
+#define TRACE_EXPORT_MARKER    BIT(2)
 
 /*
  * The trace export - an export of Ftrace output. The trace_export

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a40ee41..6048fba 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -271,6 +271,7 @@ static struct trace_export __rcu *ftrace_exports_list __read_mostly;
 
 static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled);
 static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled);
+static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled);
 
 static inline void ftrace_exports_enable(struct trace_export *export)
 {
@@ -279,6 +280,9 @@ static inline void ftrace_exports_enable(struct trace_export *export)
 
        if (export->flags & TRACE_EXPORT_EVENT)
                static_branch_inc(&trace_event_exports_enabled);
+
+       if (export->flags & TRACE_EXPORT_MARKER)
+               static_branch_inc(&trace_marker_exports_enabled);
 }
 
 static inline void ftrace_exports_disable(struct trace_export *export)
@@ -288,6 +292,9 @@ static inline void ftrace_exports_disable(struct trace_export *export)
 
        if (export->flags & TRACE_EXPORT_EVENT)
                static_branch_dec(&trace_event_exports_enabled);
+
+       if (export->flags & TRACE_EXPORT_MARKER)
+               static_branch_dec(&trace_marker_exports_enabled);
 }
 
 static void ftrace_exports(struct ring_buffer_event *event, int flag)
@@ -6687,6 +6694,8 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
        } else
                entry->buf[cnt] = '\0';
 
+       if (static_branch_unlikely(&trace_marker_exports_enabled))
+               ftrace_exports(event, TRACE_EXPORT_MARKER);
        __buffer_unlock_commit(buffer, event);
 
        if (tt)