block: Introduce IOPRIO_NR_LEVELS
The BFQ scheduler and ioprio_check_cap() both assume that the RT
priority class (IOPRIO_CLASS_RT) can have up to 8 different priority
levels, similarly to the BE class (IOPRIO_CLASS_iBE). This is
controlled using the IOPRIO_BE_NR macro , which is badly named as the
number of levels also applies to the RT class.
Introduce the class independent IOPRIO_NR_LEVELS macro, defined to 8,
to make things clear. Keep the old IOPRIO_BE_NR macro definition as an
alias for IOPRIO_NR_LEVELS.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Link: https://lore.kernel.org/r/20210811033702.368488-6-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/ioprio.c b/block/ioprio.c
index bee628f..ca6b136 100644
--- a/block/ioprio.c
+++ b/block/ioprio.c
@@ -74,9 +74,8 @@ int ioprio_check_cap(int ioprio)
fallthrough;
/* rt has prio field too */
case IOPRIO_CLASS_BE:
- if (data >= IOPRIO_BE_NR || data < 0)
+ if (data >= IOPRIO_NR_LEVELS || data < 0)
return -EINVAL;
-
break;
case IOPRIO_CLASS_IDLE:
break;