Merge tag 'optee-fix-for-v6.16' of https://git.kernel.org/pub/scm/linux/kernel/git/jenswi/linux-tee into arm/fixes

A fix in the OP-TEE driver for v6.16

Fixing a sleep in atomic context in the FF-A notification callback by
adding a work queue to process in a non-atomic context.

* tag 'optee-fix-for-v6.16' of https://git.kernel.org/pub/scm/linux/kernel/git/jenswi/linux-tee:
  optee: ffa: fix sleep in atomic context

Author: arndb

drivers/tee/optee/ffa_abi.c

@@ -728,12 +728,21 @@ static bool optee_ffa_exchange_caps(struct ffa_device *ffa_dev,
 	return true;
 }
 
+static void notif_work_fn(struct work_struct *work)
+{
+	struct optee_ffa *optee_ffa = container_of(work, struct optee_ffa,
+						   notif_work);
+	struct optee *optee = container_of(optee_ffa, struct optee, ffa);
+
+	optee_do_bottom_half(optee->ctx);
+}
+
 static void notif_callback(int notify_id, void *cb_data)
 {
 	struct optee *optee = cb_data;
 
 	if (notify_id == optee->ffa.bottom_half_value)
-		optee_do_bottom_half(optee->ctx);
+		queue_work(optee->ffa.notif_wq, &optee->ffa.notif_work);
 	else
 		optee_notif_send(optee, notify_id);
 }
@@ -817,9 +826,11 @@ static void optee_ffa_remove(struct ffa_device *ffa_dev)
 	struct optee *optee = ffa_dev_get_drvdata(ffa_dev);
 	u32 bottom_half_id = optee->ffa.bottom_half_value;
 
-	if (bottom_half_id != U32_MAX)
+	if (bottom_half_id != U32_MAX) {
 		ffa_dev->ops->notifier_ops->notify_relinquish(ffa_dev,
 							      bottom_half_id);
+		destroy_workqueue(optee->ffa.notif_wq);
+	}
 	optee_remove_common(optee);
 
 	mutex_destroy(&optee->ffa.mutex);
@@ -835,6 +846,13 @@ static int optee_ffa_async_notif_init(struct ffa_device *ffa_dev,
 	u32 notif_id = 0;
 	int rc;
 
+	INIT_WORK(&optee->ffa.notif_work, notif_work_fn);
+	optee->ffa.notif_wq = create_workqueue("optee_notification");
+	if (!optee->ffa.notif_wq) {
+		rc = -EINVAL;
+		goto err;
+	}
+
 	while (true) {
 		rc = ffa_dev->ops->notifier_ops->notify_request(ffa_dev,
 								is_per_vcpu,
@@ -851,19 +869,24 @@ static int optee_ffa_async_notif_init(struct ffa_device *ffa_dev,
 		 * notifications in that case.
 		 */
 		if (rc != -EACCES)
-			return rc;
+			goto err_wq;
 		notif_id++;
 		if (notif_id >= OPTEE_FFA_MAX_ASYNC_NOTIF_VALUE)
-			return rc;
+			goto err_wq;
 	}
 	optee->ffa.bottom_half_value = notif_id;
 
 	rc = enable_async_notif(optee);
-	if (rc < 0) {
-		ffa_dev->ops->notifier_ops->notify_relinquish(ffa_dev,
-							      notif_id);
-		optee->ffa.bottom_half_value = U32_MAX;
-	}
+	if (rc < 0)
+		goto err_rel;
+
+	return 0;
+err_rel:
+	ffa_dev->ops->notifier_ops->notify_relinquish(ffa_dev, notif_id);
+err_wq:
+	destroy_workqueue(optee->ffa.notif_wq);
+err:
+	optee->ffa.bottom_half_value = U32_MAX;
 
 	return rc;
 }

drivers/tee/optee/optee_private.h

@@ -165,6 +165,8 @@ struct optee_ffa {
 	/* Serializes access to @global_ids */
 	struct mutex mutex;
 	struct rhashtable global_ids;
+	struct workqueue_struct *notif_wq;
+	struct work_struct notif_work;
 };
 
 struct optee;