Merge pull request iovisor#1384 from pchaigno/fix-mdflush-linux-4.14

mdflush: fix for Linux 4.14
sjtuhjh · Oct 27, 2017 · 16f201f · 16f201f
2 parents 6e45749 + 3ffc80e
commit 16f201f
Showing 1 changed file with 12 additions and 1 deletion.
diff --git a/tools/mdflush.py b/tools/mdflush.py
@@ -36,8 +36,19 @@
     u32 pid = bpf_get_current_pid_tgid();
     data.pid = pid;
     bpf_get_current_comm(&data.comm, sizeof(data.comm));
+/*
+ * The following deals with a kernel version change (in mainline 4.14, although
+ * it may be backported to earlier kernels) with how the disk name is accessed.
+ * 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 bio_dev
+    bpf_probe_read(&data.disk, sizeof(data.disk), bio->bi_disk->disk_name);
+#else
     bpf_probe_read(&data.disk, sizeof(data.disk),
-        bio->bi_bdev->bd_disk->disk_name);
+                   bio->bi_bdev->bd_disk->disk_name);
+#endif
     events.perf_submit(ctx, &data, sizeof(data));
     return 0;
 }