fix biosnoop after kernel change
diff --git a/tools/biosnoop.py b/tools/biosnoop.py
index 4b8fa9f..bed6ded 100755
--- a/tools/biosnoop.py
+++ b/tools/biosnoop.py
@@ -98,11 +98,23 @@
req->rq_disk->disk_name);
}
- if (req->cmd_flags & REQ_WRITE) {
+/*
+ * The following deals with a kernel version change (in mainline 4.7, although
+ * it may be backported to earlier kernels) with how block request write flags
+ * are tested. We handle both pre- and post-change versions here. Please avoid
+ * kernel version tests like this as much as possible: they inflate the code,
+ * test, and maintenance burden.
+ */
+#ifdef REQ_WRITE
+if (req->cmd_flags & REQ_WRITE) {
+#else
+if ((req->cmd_flags >> REQ_OP_SHIFT) == REQ_OP_WRITE) {
+#endif
data.rwflag = 1;
} else {
data.rwflag = 0;
}
+
events.perf_submit(ctx, &data, sizeof(data));
start.delete(&req);
infobyreq.delete(&req);