Merge tag 'v4.9.220' into 4.9-2.3.x-imx

This is the 4.9.220 stable release

Conflicts:
	arch/arm/Kconfig.debug
	arch/arm/boot/dts/imx7s.dtsi
	arch/arm/mach-imx/common.h
	arch/arm/mach-imx/cpuidle-imx6q.c
	arch/arm/mach-imx/cpuidle-imx6sx.c
	arch/arm/mach-imx/suspend-imx6.S
	block/blk-core.c
	drivers/crypto/caam/caamalg.c
	drivers/crypto/mxs-dcp.c
	drivers/dma/imx-sdma.c
	drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
	drivers/input/keyboard/imx_keypad.c
	drivers/input/keyboard/snvs_pwrkey.c
	drivers/mmc/host/sdhci.c
	drivers/net/can/flexcan.c
	drivers/net/ethernet/freescale/fec_main.c
	drivers/net/phy/phy_device.c
	drivers/net/wireless/ath/ath10k/pci.c
	drivers/tty/serial/imx.c
	drivers/usb/dwc3/gadget.c
	drivers/usb/host/xhci.c
	include/linux/blkdev.h
	include/linux/cpu.h
	include/linux/platform_data/dma-imx-sdma.h
	kernel/cpu.c
	net/wireless/util.c
	sound/soc/fsl/Kconfig
	sound/soc/fsl/fsl_esai.c
	sound/soc/fsl/fsl_sai.c
	sound/soc/fsl/imx-sgtl5000.c

1 files changed, 32 insertions, 7 deletions

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 944de657a07a..f1e74f50642f 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -350,6 +350,7 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
 	struct usb_serial_port *port = urb->context;
 	unsigned char *data = urb->transfer_buffer;
 	unsigned long flags;
+	bool stopped = false;
 	int status = urb->status;
 	int i;
 
@@ -357,33 +358,51 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
 		if (urb == port->read_urbs[i])
 			break;
 	}
-	set_bit(i, &port->read_urbs_free);
 
 	dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
 							urb->actual_length);
 	switch (status) {
 	case 0:
+		usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
+							data);
+		port->serial->type->process_read_urb(urb);
 		break;
 	case -ENOENT:
 	case -ECONNRESET:
 	case -ESHUTDOWN:
 		dev_dbg(&port->dev, "%s - urb stopped: %d\n",
 							__func__, status);
-		return;
+		stopped = true;
+		break;
 	case -EPIPE:
 		dev_err(&port->dev, "%s - urb stopped: %d\n",
 							__func__, status);
-		return;
+		stopped = true;
+		break;
 	default:
 		dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
 							__func__, status);
-		goto resubmit;
+		break;
 	}
 
-	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
-	port->serial->type->process_read_urb(urb);
+	/*
+	 * Make sure URB processing is done before marking as free to avoid
+	 * racing with unthrottle() on another CPU. Matches the barriers
+	 * implied by the test_and_clear_bit() in
+	 * usb_serial_generic_submit_read_urb().
+	 */
+	smp_mb__before_atomic();
+	set_bit(i, &port->read_urbs_free);
+	/*
+	 * Make sure URB is marked as free before checking the throttled flag
+	 * to avoid racing with unthrottle() on another CPU. Matches the
+	 * smp_mb() in unthrottle().
+	 */
+	smp_mb__after_atomic();
+
+	if (stopped)
+		return;
 
-resubmit:
 	/* Throttle the device if requested by tty */
 	spin_lock_irqsave(&port->lock, flags);
 	port->throttled = port->throttle_req;
@@ -458,6 +477,12 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
 	port->throttled = port->throttle_req = 0;
 	spin_unlock_irq(&port->lock);
 
+	/*
+	 * Matches the smp_mb__after_atomic() in
+	 * usb_serial_generic_read_bulk_callback().
+	 */
+	smp_mb();
+
 	if (was_throttled)
 		usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 }