comp: add comp_get_copy_limits with lock

Typical use of existing comp_get_copy_limits() requires to lock the buffers for the operation to ensure consistent readings. Grouping the operations in a function simplifies the components code. It also guarantees correct double lock with dedicated flags and helps avoid a common bug in client code where single flags variable is used for both locks. When both buffers are shared between cores, and single variable is used, the rsil in second lock returns int level 5 set by the first lock. Later, during unlocking the original level returned by the first lock is not restored, the dsp stays on level 5. Signed-off-by: Marcin Maka <marcin.maka@linux.intel.com>
iganakov · Apr 7, 2020 · c94b070 · c94b070
1 parent f00c445
commit c94b070
Showing 1 changed file with 25 additions and 0 deletions.
diff --git a/src/include/sof/audio/component.h b/src/include/sof/audio/component.h
@@ -693,6 +693,31 @@ static inline void comp_overrun(struct comp_dev *dev, struct comp_buffer *sink,
 void comp_get_copy_limits(struct comp_buffer *source, struct comp_buffer *sink,
 			  struct comp_copy_limits *cl);
 
+/**
+ * Version of comp_get_copy_limits that locks both buffers to guarantee
+ * consistent state readings.
+ *
+ * @param[in] source Source buffer.
+ * @param[in] sink Sink buffer
+ * @param[out] cl Current copy limits.
+ */
+static inline
+void comp_get_copy_limits_with_lock(struct comp_buffer *source,
+				    struct comp_buffer *sink,
+				    struct comp_copy_limits *cl)
+{
+	uint32_t source_flags = 0;
+	uint32_t sink_flags = 0;
+
+	buffer_lock(source, &source_flags);
+	buffer_lock(sink, &sink_flags);
+
+	comp_get_copy_limits(source, sink, cl);
+
+	buffer_unlock(sink, sink_flags);
+	buffer_unlock(source, source_flags);
+}
+
 /**
  * Called by component in  params() function in order to set and update some of
  * downstream (playback) or upstream (capture) buffer parameters with pcm