[PATCH] arm_mpam: Reject ris_idx == MPAM_MSC_MAX_NUM_RIS

[Ping Li]

While checking the driver's partid and ris bound checks, after the
hardware team mistakenly configured PARTID_MAX in an MSC to 16,
this issue was found: MPAM_MSC_MAX_NUM_RIS is the max number of
RIS an MSC can have, so a ris_idx of 16 passes the current check,
and would later be silently truncated to 0 by FIELD_PREP(),
landing all configuration for that ris on RIS 0.

Signed-off-by: Ping Li <leeonion.muyu at gmail.com>
---
 drivers/resctrl/mpam_devices.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 48adc49b833c..347a5a6d6a1d 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -700,7 +700,7 @@ static int mpam_ris_create_locked(struct mpam_msc *msc, u8 ris_idx,
 
 	lockdep_assert_held(&mpam_list_lock);
 
-	if (ris_idx > MPAM_MSC_MAX_NUM_RIS)
+	if (ris_idx >= MPAM_MSC_MAX_NUM_RIS)
 		return -EINVAL;
 
 	if (test_and_set_bit(ris_idx, &msc->ris_idxs))
-- 
2.34.1