mei: limit the number of consecutive resets

commit 6adb8efb upstream.

give up reseting after 3 unsuccessful tries

[Backported to 3.2: files were moved]
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/staging/mei/init.c

@@ -132,6 +132,7 @@ struct mei_device *mei_device_init(struct pci_dev *pdev)
 	init_waitqueue_head(&dev->wait_recvd_msg);
 	init_waitqueue_head(&dev->wait_stop_wd);
 	dev->mei_state = MEI_INITIALIZING;
+	dev->reset_count = 0;
 	dev->iamthif_state = MEI_IAMTHIF_IDLE;
 	dev->wd_interface_reg = false;
 
@@ -290,6 +291,14 @@ void mei_reset(struct mei_device *dev, int interrupts_enabled)
 
 	dev->need_reset = false;
 
+	dev->reset_count++;
+	if (dev->reset_count > MEI_MAX_CONSEC_RESET) {
+		dev_err(&dev->pdev->dev, "reset: reached maximal consecutive resets: disabling the device\n");
+		dev->mei_state = MEI_DISABLED;
+		return;
+	}
+
+
 	if (dev->mei_state != MEI_INITIALIZING) {
 		if (dev->mei_state != MEI_DISABLED &&
 		    dev->mei_state != MEI_POWER_DOWN)

drivers/staging/mei/interrupt.c

@@ -770,6 +770,7 @@ static void mei_irq_thread_read_bus_message(struct mei_device *dev,
 					 */
 					bitmap_set(dev->host_clients_map, 0, 3);
 					dev->mei_state = MEI_ENABLED;
+					dev->reset_count = 0;
 
 					/* if wd initialization fails, initialization the AMTHI client,
 					 * otherwise the AMTHI client will be initialized after the WD client connect response
@@ -1527,7 +1528,8 @@ void mei_timer(struct work_struct *work)
 		}
 	}
 out:
-	 schedule_delayed_work(&dev->timer_work, 2 * HZ);
+	 if (dev->mei_state != MEI_DISABLED)
+		schedule_delayed_work(&dev->timer_work, 2 * HZ);
 	 mutex_unlock(&dev->device_lock);
 }
 

drivers/staging/mei/mei_dev.h

@@ -63,6 +63,11 @@ extern const uuid_le mei_wd_guid;
  */
 extern const u8 mei_wd_state_independence_msg[3][4];
 
+/*
+ * maximum number of consecutive resets
+ */
+#define MEI_MAX_CONSEC_RESET  3
+
 /*
  * Number of File descriptors/handles
  * that can be opened to the driver.
@@ -178,7 +183,11 @@ struct mei_io_list {
 	int status;
 };
 
-/* MEI private device struct */
+/**
+ * mei_device - MEI private device struct
+ *
+ * @reset_count - limits the number of consecutive resets
+ */
 struct mei_device {
 	struct pci_dev *pdev;	/* pointer to pci device struct */
 	/*
@@ -225,6 +234,7 @@ struct mei_device {
 	/*
 	 * mei device  states
 	 */
+	unsigned long reset_count;
 	enum mei_states mei_state;
 	enum mei_init_clients_states init_clients_state;
 	u16 init_clients_timer;