firmware: arm_scmi: Relax duplicate name constraint across protocol ids

[ Upstream commit 21ee965 ]

Currently in scmi_protocol_device_request(), no duplicate scmi device
name is allowed across any protocol. However scmi_dev_match_id() first
matches the protocol id and then the name. So, there is no strict
requirement to keep this scmi device name unique across all the protocols.

Relax the constraint on the duplicate name across the protocols and
inhibit only within the same protocol id.

Message-Id: <[email protected]>
Reviewed-by: Dhruva Gole <[email protected]>
Reviewed-by: Peng Fan <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: sudeep-holla

drivers/firmware/arm_scmi/bus.c

@@ -42,7 +42,7 @@ static atomic_t scmi_syspower_registered = ATOMIC_INIT(0);
  * This helper let an SCMI driver request specific devices identified by the
  * @id_table to be created for each active SCMI instance.
  *
- * The requested device name MUST NOT be already existent for any protocol;
+ * The requested device name MUST NOT be already existent for this protocol;
  * at first the freshly requested @id_table is annotated in the IDR table
  * @scmi_requested_devices and then the requested device is advertised to any
  * registered party via the @scmi_requested_devices_nh notification chain.
@@ -52,7 +52,6 @@ static atomic_t scmi_syspower_registered = ATOMIC_INIT(0);
 static int scmi_protocol_device_request(const struct scmi_device_id *id_table)
 {
 	int ret = 0;
-	unsigned int id = 0;
 	struct list_head *head, *phead = NULL;
 	struct scmi_requested_dev *rdev;
 
@@ -67,19 +66,13 @@ static int scmi_protocol_device_request(const struct scmi_device_id *id_table)
 	}
 
 	/*
-	 * Search for the matching protocol rdev list and then search
-	 * of any existent equally named device...fails if any duplicate found.
+	 * Find the matching protocol rdev list and then search of any
+	 * existent equally named device...fails if any duplicate found.
 	 */
 	mutex_lock(&scmi_requested_devices_mtx);
-	idr_for_each_entry(&scmi_requested_devices, head, id) {
-		if (!phead) {
-			/* A list found registered in the IDR is never empty */
-			rdev = list_first_entry(head, struct scmi_requested_dev,
-						node);
-			if (rdev->id_table->protocol_id ==
-			    id_table->protocol_id)
-				phead = head;
-		}
+	phead = idr_find(&scmi_requested_devices, id_table->protocol_id);
+	if (phead) {
+		head = phead;
 		list_for_each_entry(rdev, head, node) {
 			if (!strcmp(rdev->id_table->name, id_table->name)) {
 				pr_err("Ignoring duplicate request [%d] %s\n",