mei: synchronize irq before initiating a reset.

We need to synchronize irqs before issuing reset to make sure that the
clients communication is concluded and doesn't leak to the reset flow
and confusing the state machine.

This issue is happening during suspend/resume stress testing.

Signed-off-by: Tomas Winkler <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/mei/hw-me.c

···
 }
 
 /**
+ * mei_me_synchronize_irq - wait for pending IRQ handlers
+ *
+ * @dev: the device structure
+ */
+static void mei_me_synchronize_irq(struct mei_device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+
+	synchronize_irq(pdev->irq);
+}
+
+/**
  * mei_me_hw_reset_release - release device from the reset
  *
  * @dev: the device structure
···
 	.intr_clear = mei_me_intr_clear,
 	.intr_enable = mei_me_intr_enable,
 	.intr_disable = mei_me_intr_disable,
+	.synchronize_irq = mei_me_synchronize_irq,
 
 	.hbuf_free_slots = mei_me_hbuf_empty_slots,
 	.hbuf_is_ready = mei_me_hbuf_is_empty,

drivers/misc/mei/hw-txe.c

···
 #include <linux/ktime.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
-#include <linux/irqreturn.h>
+#include <linux/interrupt.h>
 #include <linux/pm_runtime.h>
 
 #include <linux/mei.h>
···
 
 	mei_txe_br_reg_write(hw, HHIER_REG, IPC_HHIER_MSK);
 	mei_txe_br_reg_write(hw, HIER_REG, HIER_INT_EN_MSK);
+}
+
+/**
+ * mei_txe_synchronize_irq - wait for pending IRQ handlers
+ *
+ * @dev: the device structure
+ */
+static void mei_txe_synchronize_irq(struct mei_device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev->dev);
+
+	synchronize_irq(pdev->irq);
 }
 
 /**
···
 	.intr_clear = mei_txe_intr_clear,
 	.intr_enable = mei_txe_intr_enable,
 	.intr_disable = mei_txe_intr_disable,
+	.synchronize_irq = mei_txe_synchronize_irq,
 
 	.hbuf_free_slots = mei_txe_hbuf_empty_slots,
 	.hbuf_is_ready = mei_txe_is_input_ready,

drivers/misc/mei/init.c

···
 			 mei_dev_state_str(state), fw_sts_str);
 	}
 
+	mei_clear_interrupts(dev);
+
+	mei_synchronize_irq(dev);
+
 	/* we're already in reset, cancel the init timer
 	 * if the reset was called due the hbm protocol error
 	 * we need to call it before hw start
···
 	int err;
 
 	mutex_lock(&dev->device_lock);
-
-	mei_clear_interrupts(dev);
 
 	dev->dev_state = MEI_DEV_POWER_UP;
 	dev->reset_count = 0;

drivers/misc/mei/mei_dev.h

···
  * @intr_clear       : clear pending interrupts
  * @intr_enable      : enable interrupts
  * @intr_disable     : disable interrupts
+ * @synchronize_irq  : synchronize irqs
  *
  * @hbuf_free_slots  : query for write buffer empty slots
  * @hbuf_is_ready    : query if write buffer is empty
···
 	int (*hw_start)(struct mei_device *dev);
 	void (*hw_config)(struct mei_device *dev);
 
-
 	int (*fw_status)(struct mei_device *dev, struct mei_fw_status *fw_sts);
 	enum mei_pg_state (*pg_state)(struct mei_device *dev);
 	bool (*pg_in_transition)(struct mei_device *dev);
···
 	void (*intr_clear)(struct mei_device *dev);
 	void (*intr_enable)(struct mei_device *dev);
 	void (*intr_disable)(struct mei_device *dev);
+	void (*synchronize_irq)(struct mei_device *dev);
 
 	int (*hbuf_free_slots)(struct mei_device *dev);
 	bool (*hbuf_is_ready)(struct mei_device *dev);
···
 static inline void mei_disable_interrupts(struct mei_device *dev)
 {
 	dev->ops->intr_disable(dev);
+}
+
+static inline void mei_synchronize_irq(struct mei_device *dev)
+{
+	dev->ops->synchronize_irq(dev);
 }
 
 static inline bool mei_host_is_ready(struct mei_device *dev)