[PATCH v5 2/3] firmware: arm_scmi: Fix scmi_protocol_table_register() error handling

[Hans de Goede]

scmi_protocol_table_register() stops at the first failure to request
one of the scmi_device_id-s into scmi_requested_devices, but it leaves any
previously successfully requested device-ids in place.

Unrequest any successfully requested device-ids on error to fix this.

The code manually unrequests these rather then calling
scmi_protocol_table_unregister() because one way this can fail is because
of duplicate device-ids and in that case the original device-id must not
be unrequested.

This also moves scmi_protocol_table_register() to below
scmi_protocol_device_unrequest() since it now calls that local function.

Signed-off-by: Hans de Goede <johannes.goede at oss.qualcomm.com>
---
Changes in v5:
- New patch in v5 of this series
---
 drivers/firmware/arm_scmi/bus.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c
index d12d5de15a1a..6f667e4ffeed 100644
--- a/drivers/firmware/arm_scmi/bus.c
+++ b/drivers/firmware/arm_scmi/bus.c
@@ -137,17 +137,6 @@ static int scmi_protocol_device_request(const struct scmi_device_id *id_table)
 	return ret;
 }
 
-static int scmi_protocol_table_register(const struct scmi_device_id *id_table)
-{
-	int ret = 0;
-	const struct scmi_device_id *entry;
-
-	for (entry = id_table; entry->name[0] && ret == 0; entry++)
-		ret = scmi_protocol_device_request(entry);
-
-	return ret;
-}
-
 /**
  * scmi_protocol_device_unrequest  - Helper to unrequest a device
  *
@@ -193,6 +182,25 @@ static void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table
 	mutex_unlock(&scmi_requested_devices_mtx);
 }
 
+static int scmi_protocol_table_register(const struct scmi_device_id *id_table)
+{
+	int i, ret;
+
+	for (i = 0; id_table[i].name[0]; i++) {
+		ret = scmi_protocol_device_request(&id_table[i]);
+		if (ret)
+			goto error;
+	}
+
+	return 0;
+
+error:
+	while (--i >= 0)
+		scmi_protocol_device_unrequest(&id_table[i]);
+
+	return ret;
+}
+
 static void
 scmi_protocol_table_unregister(const struct scmi_device_id *id_table)
 {
-- 
2.55.0