[PATCH v3 06/16] arm_mpam: propagate MSC read errors for __ris_msmon_read()

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

Allow the function for RIS accesses 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 | 23 +++++++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 041fca018e68..84a8715464be 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1297,6 +1297,10 @@ static u64 mpam_msmon_overflow_val(enum mpam_device_features type,
 	return overflow_val;
 }
 
+/*
+ * This function might be called via smp_call_function_any(), so propagate
+ * errors inside the arg struct.
+ */
 static void __ris_msmon_read(void *arg)
 {
 	u64 now;
@@ -1339,7 +1343,9 @@ static void __ris_msmon_read(void *arg)
 	 * Read the existing configuration to avoid re-writing the same values.
 	 * This saves waiting for 'nrdy' on subsequent reads.
 	 */
-	read_msmon_ctl_flt_vals(m, &cur_ctl, &cur_flt);
+	ret = read_msmon_ctl_flt_vals(m, &cur_ctl, &cur_flt);
+	if (ret)
+		goto out_unlock;
 
 	if (mpam_feat_msmon_mbwu_31counter == m->type)
 		overflow = cur_ctl & MSMON_CFG_x_CTL_OFLOW_STATUS;
@@ -1364,7 +1370,9 @@ static void __ris_msmon_read(void *arg)
 
 	switch (m->type) {
 	case mpam_feat_msmon_csu:
-		mpam_read_monsel_reg(msc, CSU, &now32);
+		ret = mpam_read_monsel_reg(msc, CSU, &now32);
+		if (ret)
+			goto out_unlock;
 		nrdy = now32 & MSMON___NRDY;
 		now = FIELD_GET(MSMON___VALUE, now32);
 
@@ -1385,7 +1393,9 @@ static void __ris_msmon_read(void *arg)
 			else
 				now = FIELD_GET(MSMON___L_VALUE, now);
 		} else {
-			mpam_read_monsel_reg(msc, MBWU, &now32);
+			ret = mpam_read_monsel_reg(msc, MBWU, &now32);
+			if (ret)
+				goto out_unlock;
 			nrdy = now32 & MSMON___NRDY;
 			now = FIELD_GET(MSMON___VALUE, now32);
 		}
@@ -1748,6 +1758,7 @@ static int mpam_restore_mbwu_state(void *_ris)
 {
 	int i;
 	u64 val;
+	int ret = 0;
 	struct mon_read mwbu_arg;
 	struct mpam_msc_ris *ris = _ris;
 	struct mpam_class *class = ris->vmsc->comp->class;
@@ -1760,10 +1771,14 @@ static int mpam_restore_mbwu_state(void *_ris)
 			mwbu_arg.val = &val;
 
 			__ris_msmon_read(&mwbu_arg);
+			if (mwbu_arg.err) {
+				ret = mwbu_arg.err;
+				break;
+			}
 		}
 	}
 
-	return 0;
+	return ret;
 }
 
 /* Call with MSC cfg_lock held */
-- 
2.43.0