[PATCH v2 06/15] 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 | 35 +++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index b259fe20a614..d18c7be86aaa 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1285,9 +1285,14 @@ 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;
+	int ret;
 	u32 now32;
 	bool nrdy = false;
 	bool config_mismatch;
@@ -1326,7 +1331,9 @@ 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;
@@ -1351,7 +1358,9 @@ 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);
 
@@ -1371,7 +1380,9 @@ 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);
 		}
@@ -1402,10 +1413,15 @@ static void __ris_msmon_read(void *arg)
 	if (nrdy)
 		m->err = -EBUSY;
 
-	if (m->err)
-		return;
+	if (!m->err)
+		*m->val += now;
+
+	return;
 
-	*m->val += now;
+out_unlock:
+	mpam_mon_sel_unlock(msc);
+
+	m->err = ret;
 }
 
 static int _msmon_read(struct mpam_component *comp, struct mon_read *arg)
@@ -1729,6 +1745,7 @@ 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;
@@ -1741,10 +1758,14 @@ 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