1 files changed, 47 insertions, 4 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 7a34cb563fec..d9d6206e0b14 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -65,13 +65,15 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
 {
         struct blk_io_trace *t;
         struct ring_buffer_event *event = NULL;
+        struct ring_buffer *buffer = NULL;
         int pc = 0;
         int cpu = smp_processor_id();
         bool blk_tracer = blk_tracer_enabled;
 
         if (blk_tracer) {
+                buffer = blk_tr->buffer;
                 pc = preempt_count();
-                event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
+                event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
                                                   sizeof(*t) + len,
                                                   0, pc);
                 if (!event)
@@ -96,7 +98,7 @@ record_it:
                 memcpy((void *) t + sizeof(*t), data, len);
 
                 if (blk_tracer)
-                        trace_buffer_unlock_commit(blk_tr, event, 0, pc);
+                        trace_buffer_unlock_commit(buffer, event, 0, pc);
         }
 }
 
@@ -179,6 +181,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 {
         struct task_struct *tsk = current;
         struct ring_buffer_event *event = NULL;
+        struct ring_buffer *buffer = NULL;
         struct blk_io_trace *t;
         unsigned long flags = 0;
         unsigned long *sequence;
@@ -204,8 +207,9 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
         if (blk_tracer) {
                 tracing_record_cmdline(current);
 
+                buffer = blk_tr->buffer;
                 pc = preempt_count();
-                event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
+                event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
                                                   sizeof(*t) + pdu_len,
                                                   0, pc);
                 if (!event)
@@ -252,7 +256,7 @@ record_it:
                         memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
 
                 if (blk_tracer) {
-                        trace_buffer_unlock_commit(blk_tr, event, 0, pc);
+                        trace_buffer_unlock_commit(buffer, event, 0, pc);
                         return;
                 }
         }
@@ -852,6 +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
@@ -918,10 +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);
@@ -1653,6 +1691,11 @@ int blk_trace_init_sysfs(struct device *dev)
         return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
 }
 
+void blk_trace_remove_sysfs(struct device *dev)
+{
+        sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
+}
+
 #endif /* CONFIG_BLK_DEV_IO_TRACE */
 
 #ifdef CONFIG_EVENT_TRACING