scsi: add tracepoint for scsi_req_cancel

Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

hw/scsi-bus.c

@@ -1496,6 +1496,7 @@ void scsi_req_complete(SCSIRequest *req, int status)
 
 void scsi_req_cancel(SCSIRequest *req)
 {
+    trace_scsi_req_cancel(req->dev->id, req->lun, req->tag);
     if (!req->enqueued) {
         return;
     }

trace-events

@@ -403,6 +403,7 @@ usb_host_parse_error(int bus, int addr, const char *errmsg) "dev %d:%d, msg %s"
 
 # hw/scsi-bus.c
 scsi_req_alloc(int target, int lun, int tag) "target %d lun %d tag %d"
+scsi_req_cancel(int target, int lun, int tag) "target %d lun %d tag %d"
 scsi_req_data(int target, int lun, int tag, int len) "target %d lun %d tag %d len %d"
 scsi_req_data_canceled(int target, int lun, int tag, int len) "target %d lun %d tag %d len %d"
 scsi_req_dequeue(int target, int lun, int tag) "target %d lun %d tag %d"