On Sat, Aug 07, 2021 at 10:16:39AM -0600, Jens Axboe wrote:

quoted

 /*
- * 8 best effort priority levels are supported
+ * The RT and BE priority classes both support up to 8 priority levels.
  */
-#define IOPRIO_BE_NR	8
+#define IOPRIO_NR_LEVELS	8

That might not be a good idea, if an application already uses
IOPRIO_BE_NR...

The constant has not actually been exposed in a uapi header in any
released kernel, so if there is a time to rename it it is now.