[PATCH v8 07/21] tracing/simple_ring_buffer: Add support for compressed length

@@ -207,7 +207,13 @@ static unsigned long rb_event_size(unsigned long length)
 {
 	struct ring_buffer_event *event;
 
-	return length + RB_EVNT_HDR_SIZE + sizeof(event->array[0]);
+	if (!length)
+		length++;
+
+	if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT)
+		length += sizeof(event->array[0]);
+
+	return ALIGN(length + RB_EVNT_HDR_SIZE, RB_ARCH_ALIGNMENT);
 }
 
 static struct ring_buffer_event *

@@ -223,12 +229,15 @@ rb_event_add_ts_extend(struct ring_buffer_event *event, u64 delta)
 static struct ring_buffer_event *
 simple_rb_reserve_next(struct simple_rb_per_cpu *cpu_buffer, unsigned long length, u64 timestamp)
 {
-	unsigned long ts_ext_size = 0, event_size = rb_event_size(length);
 	struct simple_buffer_page *tail = cpu_buffer->tail_page;
+	unsigned long event_size, array_size, ts_ext_size = 0;
 	struct ring_buffer_event *event;
 	u32 write, prev_write;
 	u64 time_delta;
 
+	event_size = rb_event_size(length);
+	array_size = event_size - RB_EVNT_HDR_SIZE;
+
 	time_delta = timestamp - cpu_buffer->write_stamp;
 
 	if (test_time_stamp(time_delta))

@@ -259,9 +268,13 @@ simple_rb_reserve_next(struct simple_rb_per_cpu *cpu_buffer, unsigned long lengt
 		time_delta = 0;
 	}
 
-	event->type_len = 0;
+	if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT) {
+		event->type_len = 0;
+		event->array[0] = array_size;
+	} else {
+		event->type_len = DIV_ROUND_UP(array_size, RB_ALIGNMENT);
+	}
 	event->time_delta = time_delta;
-	event->array[0] = event_size - RB_EVNT_HDR_SIZE;
 
 	return event;
 }

@@ -284,7 +297,7 @@ void *simple_ring_buffer_reserve(struct simple_rb_per_cpu *cpu_buffer, unsigned
 
 	rb_event = simple_rb_reserve_next(cpu_buffer, length, timestamp);
 
-	return &rb_event->array[1];
+	return rb_event->type_len ? &rb_event->array[0] : &rb_event->array[1];
 }
 EXPORT_SYMBOL_GPL(simple_ring_buffer_reserve);