oprofile: adding cpu_buffer_write_commit()

This is in preparation for changes in the cpu buffer implementation.
Signed-off-by: Robert Richter <robert.richter@amd.com>

drivers/oprofile/cpu_buffer.c

@@ -148,22 +148,6 @@ static unsigned long nr_available_slots(struct oprofile_cpu_buffer const *b)
 	return tail + (b->buffer_size - head) - 1;
 }
 
-static void increment_head(struct oprofile_cpu_buffer *b)
-{
-	unsigned long new_head = b->head_pos + 1;
-
-	/*
-	 * Ensure anything written to the slot before we increment is
-	 * visible
-	 */
-	wmb();
-
-	if (new_head < b->buffer_size)
-		b->head_pos = new_head;
-	else
-		b->head_pos = 0;
-}
-
 static inline void
 add_sample(struct oprofile_cpu_buffer *cpu_buf,
 	   unsigned long pc, unsigned long event)
@@ -171,7 +155,7 @@ add_sample(struct oprofile_cpu_buffer *cpu_buf,
 	struct op_sample *entry = cpu_buffer_write_entry(cpu_buf);
 	entry->eip = pc;
 	entry->event = event;
-	increment_head(cpu_buf);
+	cpu_buffer_write_commit(cpu_buf);
 }
 
 static inline void

drivers/oprofile/cpu_buffer.h

@@ -58,6 +58,23 @@ struct op_sample *cpu_buffer_write_entry(struct oprofile_cpu_buffer *cpu_buf)
 	return &cpu_buf->buffer[cpu_buf->head_pos];
 }
 
+static inline
+void cpu_buffer_write_commit(struct oprofile_cpu_buffer *b)
+{
+	unsigned long new_head = b->head_pos + 1;
+
+	/*
+	 * Ensure anything written to the slot before we increment is
+	 * visible
+	 */
+	wmb();
+
+	if (new_head < b->buffer_size)
+		b->head_pos = new_head;
+	else
+		b->head_pos = 0;
+}
+
 static inline
 struct op_sample *cpu_buffer_read_entry(struct oprofile_cpu_buffer *cpu_buf)
 {