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From:   Tingwei Zhang <tingwei@codeaurora.org>
To:     Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>
Cc:     Tingwei Zhang <tingwei@codeaurora.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        tsoni@codeaurora.org,
        Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
        Mao Jinlong <jinlmao@codeaurora.org>,
        linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 4/6] tracing: add trace_export support for trace_marker
Date:   Sat, 26 Sep 2020 09:00:03 +0800
Message-Id: <20200926010005.14689-5-tingwei@codeaurora.org>
In-Reply-To: <20200926010005.14689-1-tingwei@codeaurora.org>
References: <20200926010005.14689-1-tingwei@codeaurora.org>
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Add the support to route trace_marker buffer to other destination
via trace_export.

Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
 include/linux/trace.h | 1 +
 kernel/trace/trace.c  | 9 +++++++++
 2 files changed, 10 insertions(+)

diff --git a/include/linux/trace.h b/include/linux/trace.h
index 86033d214972..886a4ffd9d45 100644
--- 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 a40ee413123c..6048fba2f590 100644
--- 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)
-- 
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