4 files changed, 29 insertions, 2 deletions

diff --git a/kernel/ethosu_device.c b/kernel/ethosu_device.c
index 1a2e7f7..ae257c3 100644
--- a/kernel/ethosu_device.c
+++ b/kernel/ethosu_device.c
@@ -522,7 +522,10 @@ void ethosu_dev_deinit(struct rpmsg_device *rpdev)
 
 	dev_info(dev, "%s", __FUNCTION__);
 
+	device_lock(&edev->dev);
 	ethosu_mailbox_fail(&edev->mailbox);
+	device_unlock(&edev->dev);
+
 	rpmsg_destroy_ept(edev->ept);
 	cdev_del(&edev->cdev);
 	device_unregister(&edev->dev);
diff --git a/kernel/ethosu_inference.c b/kernel/ethosu_inference.c
index dd0b7b9..bc38236 100644
--- a/kernel/ethosu_inference.c
+++ b/kernel/ethosu_inference.c
@@ -179,7 +179,9 @@ static int ethosu_inference_release(struct inode *inode,
 		 "Inference release. file=0x%pK, inf=0x%pK",
 		 file, inf);
 
+	device_lock(dev);
 	ethosu_inference_put(inf);
+	device_unlock(dev);
 
 	return 0;
 }
diff --git a/kernel/ethosu_mailbox.c b/kernel/ethosu_mailbox.c
index 3e7284b..5b105d8 100644
--- a/kernel/ethosu_mailbox.c
+++ b/kernel/ethosu_mailbox.c
@@ -31,6 +31,7 @@
 #include <linux/jiffies.h>
 #include <linux/resource.h>
 #include <linux/uio.h>
+#include <linux/bug.h>
 
 /****************************************************************************
  * Includes
@@ -65,6 +66,7 @@ static void ethosu_core_set_capacity(struct ethosu_buffer *buf,
 int ethosu_mailbox_register(struct ethosu_mailbox *mbox,
 			    struct ethosu_mailbox_msg *msg)
 {
+	WARN_ON_ONCE(!mutex_is_locked(&mbox->dev->mutex));
 	msg->id = idr_alloc_cyclic(&mbox->msg_idr, msg, 0, INT_MAX, GFP_KERNEL);
 	if (msg->id < 0)
 		return msg->id;
@@ -75,6 +77,7 @@ int ethosu_mailbox_register(struct ethosu_mailbox *mbox,
 void ethosu_mailbox_deregister(struct ethosu_mailbox *mbox,
 			       struct ethosu_mailbox_msg *msg)
 {
+	WARN_ON_ONCE(!mutex_is_locked(&mbox->dev->mutex));
 	idr_remove(&mbox->msg_idr, msg->id);
 }
 
@@ -82,8 +85,10 @@ struct ethosu_mailbox_msg *ethosu_mailbox_find(struct ethosu_mailbox *mbox,
 					       int msg_id,
 					       uint32_t msg_type)
 {
-	struct ethosu_mailbox_msg *ptr = (struct ethosu_mailbox_msg *)idr_find(
-		&mbox->msg_idr, msg_id);
+	struct ethosu_mailbox_msg *ptr;
+
+	WARN_ON_ONCE(!mutex_is_locked(&mbox->dev->mutex));
+	ptr = (struct ethosu_mailbox_msg *)idr_find(&mbox->msg_idr, msg_id);
 
 	if (ptr == NULL)
 		return ERR_PTR(-ENOENT);
@@ -99,6 +104,7 @@ void ethosu_mailbox_fail(struct ethosu_mailbox *mbox)
 	struct ethosu_mailbox_msg *cur;
 	int id;
 
+	WARN_ON_ONCE(!mutex_is_locked(&mbox->dev->mutex));
 	idr_for_each_entry(&mbox->msg_idr, cur, id) {
 		cur->fail(cur);
 	}
diff --git a/kernel/ethosu_mailbox.h b/kernel/ethosu_mailbox.h
index c192b54..ea4409f 100644
--- a/kernel/ethosu_mailbox.h
+++ b/kernel/ethosu_mailbox.h
@@ -50,6 +50,14 @@ struct ethosu_mailbox {
 	struct idr            msg_idr;
 };
 
+/**
+ * struct ethosu_mailbox_msg - Mailbox message
+ * @id: Message id
+ * @type: Message request type
+ * @fail: Message failure callback
+ *
+ * The fail callback will be called with the device mutex locked
+ */
 struct ethosu_mailbox_msg {
 	int      id;
 	uint32_t type;
@@ -77,6 +85,8 @@ void ethosu_mailbox_deinit(struct ethosu_mailbox *mbox);
 /**
  * ethosu_mailbox_register() - Register the ethosu_mailbox_msg in ethosu_mailbox
  *
+ * Context: Must be called with the device mutex locked
+ *
  * Return: 0 on success, else error code.
  */
 int ethosu_mailbox_register(struct ethosu_mailbox *mbox,
@@ -84,6 +94,8 @@ int ethosu_mailbox_register(struct ethosu_mailbox *mbox,
 
 /**
  * ethosu_mailbox_free_id() - Free the id of the ethosu_mailbox_msg
+ *
+ * Context: Must be called with the device mutex locked
  */
 void ethosu_mailbox_deregister(struct ethosu_mailbox *mbox,
 			       struct ethosu_mailbox_msg *msg);
@@ -91,6 +103,8 @@ void ethosu_mailbox_deregister(struct ethosu_mailbox *mbox,
 /**
  * ethosu_mailbox_find() - Find mailbox message
  *
+ * Context: Must be called with the device mutex locked
+ *
  * Return: a valid pointer on success, otherwise an error ptr.
  */
 struct ethosu_mailbox_msg *ethosu_mailbox_find(struct ethosu_mailbox *mbox,
@@ -101,6 +115,8 @@ struct ethosu_mailbox_msg *ethosu_mailbox_find(struct ethosu_mailbox *mbox,
  * ethosu_mailbox_fail() - Fail mailbox messages
  *
  * Call fail() callback on all messages in pending list.
+ *
+ * Context: Must be called with the device mutex locked
  */
 void ethosu_mailbox_fail(struct ethosu_mailbox *mbox);