[PATCH v2 04/15] arm_mpam: propagate MSC read errors for mpam_msc_read_mbwu_l()

[Andre Przywara <andre.przywara@arm.com>]

Allow the mpam_msc_read_mbwu_l() function to return an error, and
propagate read errors from the lower level up.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 drivers/resctrl/mpam_devices.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 011d1e3544d7..1d06902fb970 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1106,6 +1106,7 @@ static bool mpam_ris_has_mbwu_long_counter(struct mpam_msc_ris *ris)
 
 static u64 mpam_msc_read_mbwu_l(struct mpam_msc *msc)
 {
+	int ret;
 	int retry = 3;
 	u32 mbwu_l_low;
 	u32 mbwu_l_high1, mbwu_l_high2;
@@ -1115,11 +1116,17 @@ static u64 mpam_msc_read_mbwu_l(struct mpam_msc *msc)
 	WARN_ON_ONCE((MSMON_MBWU_L + sizeof(u64)) > msc->mapped_hwpage_sz);
 	WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &msc->accessibility));
 
-	__mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2);
+	ret = __mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2);
+	if (ret)
+		return MSMON___L_NRDY;
+
 	do {
 		mbwu_l_high1 = mbwu_l_high2;
-		__mpam_read_reg(msc, MSMON_MBWU_L, &mbwu_l_low);
-		__mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2);
+		ret = __mpam_read_reg(msc, MSMON_MBWU_L, &mbwu_l_low);
+		if (!ret)
+			ret = __mpam_read_reg(msc, MSMON_MBWU_L + 4, &mbwu_l_high2);
+		if (ret)
+			return MSMON___L_NRDY;
 
 		retry--;
 	} while (mbwu_l_high1 != mbwu_l_high2 && retry > 0);
-- 
2.43.0