Add a tracepoint for block request remapping

[safe/jmp/linux-2.6] / kernel / trace / blktrace.c

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 60b5c5a..d9d6206 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -856,6 +856,37 @@ static void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
 }
 
 /**
+ * blk_add_trace_rq_remap - Add a trace for a request-remap operation
+ * @q:         queue the io is for
+ * @rq:                the source request
+ * @dev:       target device
+ * @from:      source sector
+ *
+ * Description:
+ *     Device mapper remaps request to other devices.
+ *     Add a trace for that action.
+ *
+ **/
+static void blk_add_trace_rq_remap(struct request_queue *q,
+                                  struct request *rq, dev_t dev,
+                                  sector_t from)
+{
+       struct blk_trace *bt = q->blk_trace;
+       struct blk_io_trace_remap r;
+
+       if (likely(!bt))
+               return;
+
+       r.device_from = cpu_to_be32(dev);
+       r.device_to   = cpu_to_be32(disk_devt(rq->rq_disk));
+       r.sector_from = cpu_to_be64(from);
+
+       __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
+                       rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
+                       sizeof(r), &r);
+}
+
+/**
  * blk_add_driver_data - Add binary message with driver-specific data
  * @q:         queue the io is for
  * @rq:                io request
@@ -922,10 +953,13 @@ static void blk_register_tracepoints(void)
        WARN_ON(ret);
        ret = register_trace_block_remap(blk_add_trace_remap);
        WARN_ON(ret);
+       ret = register_trace_block_rq_remap(blk_add_trace_rq_remap);
+       WARN_ON(ret);
 }
 
 static void blk_unregister_tracepoints(void)
 {
+       unregister_trace_block_rq_remap(blk_add_trace_rq_remap);
        unregister_trace_block_remap(blk_add_trace_remap);
        unregister_trace_block_split(blk_add_trace_split);
        unregister_trace_block_unplug_io(blk_add_trace_unplug_io);