habanalabs: print if device is used on FD close

Notify to the user that although he closed the FD, the device is
still in use because there are live CS and/or memory mappings (mmaps).
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>

drivers/misc/habanalabs/common/device.c

@@ -80,9 +80,9 @@ void hl_hpriv_get(struct hl_fpriv *hpriv)
 	kref_get(&hpriv->refcount);
 }
 
-void hl_hpriv_put(struct hl_fpriv *hpriv)
+int hl_hpriv_put(struct hl_fpriv *hpriv)
 {
-	kref_put(&hpriv->refcount, hpriv_release);
+	return kref_put(&hpriv->refcount, hpriv_release);
 }
 
 /*
@@ -109,7 +109,9 @@ static int hl_device_release(struct inode *inode, struct file *filp)
 	hl_cb_mgr_fini(hdev, &hpriv->cb_mgr);
 	hl_ctx_mgr_fini(hdev, &hpriv->ctx_mgr);
 
-	hl_hpriv_put(hpriv);
+	if (!hl_hpriv_put(hpriv))
+		dev_warn(hdev->dev,
+			"Device is still in use because there are live CS and/or memory mappings\n");
 
 	return 0;
 }

drivers/misc/habanalabs/common/habanalabs.h

@@ -2182,7 +2182,7 @@ int hl_device_resume(struct hl_device *hdev);
 int hl_device_reset(struct hl_device *hdev, bool hard_reset,
 			bool from_hard_reset_thread);
 void hl_hpriv_get(struct hl_fpriv *hpriv);
-void hl_hpriv_put(struct hl_fpriv *hpriv);
+int hl_hpriv_put(struct hl_fpriv *hpriv);
 int hl_device_set_frequency(struct hl_device *hdev, enum hl_pll_frequency freq);
 uint32_t hl_device_utilization(struct hl_device *hdev, uint32_t period_ms);