[PATCH 5/5] comedi: vmk80xx: report failed transfers of the K8061

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Josef Bacik <josef@toxicpanda.com>

For the K8061 board vmk80xx_read_packet() and vmk80xx_write_packet() call
vmk80xx_do_bulk_msg(), which ignores the result of its two bulk transfers,
and return 0. After a timeout, a stall or an unplug the instruction
handlers therefore go on and hand the old content of usb_rx_buf to user
space as a fresh sample (analog and digital inputs, counters, PWM and
output read-back), and writes to the outputs are reported as done.

All callers check the result already, because the K8055 branch of the two
functions returns that of usb_interrupt_msg(). Return the error of the
bulk transfers as well, and don't wait for an answer to a command that
could not be sent.

Fixes: 985cafccbf9b ("Staging: Comedi: vmk80xx: Add k8061 support")
Cc: stable <stable@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/comedi/drivers/vmk80xx.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/drivers/comedi/drivers/vmk80xx.c b/drivers/comedi/drivers/vmk80xx.c
index 84dce5184a77..ddb12b48c8a4 100644
--- a/drivers/comedi/drivers/vmk80xx.c
+++ b/drivers/comedi/drivers/vmk80xx.c
@@ -151,7 +151,7 @@ struct vmk80xx_private {
 	enum vmk80xx_model model;
 };
 
-static void vmk80xx_do_bulk_msg(struct comedi_device *dev)
+static int vmk80xx_do_bulk_msg(struct comedi_device *dev)
 {
 	struct vmk80xx_private *devpriv = dev->private;
 	struct usb_device *usb = comedi_to_usb_dev(dev);
@@ -161,6 +161,7 @@ static void vmk80xx_do_bulk_msg(struct comedi_device *dev)
 	unsigned int rx_pipe;
 	size_t tx_size;
 	size_t rx_size;
+	int ret;
 
 	tx_addr = devpriv->ep_tx->bEndpointAddress;
 	rx_addr = devpriv->ep_rx->bEndpointAddress;
@@ -169,11 +170,13 @@ static void vmk80xx_do_bulk_msg(struct comedi_device *dev)
 	tx_size = usb_endpoint_maxp(devpriv->ep_tx);
 	rx_size = usb_endpoint_maxp(devpriv->ep_rx);
 
-	usb_bulk_msg(usb, tx_pipe, devpriv->usb_tx_buf, tx_size, NULL,
-		     PACKET_TIMEOUT);
+	ret = usb_bulk_msg(usb, tx_pipe, devpriv->usb_tx_buf, tx_size, NULL,
+			   PACKET_TIMEOUT);
+	if (ret)
+		return ret;
 
-	usb_bulk_msg(usb, rx_pipe, devpriv->usb_rx_buf, rx_size, NULL,
-		     PACKET_TIMEOUT);
+	return usb_bulk_msg(usb, rx_pipe, devpriv->usb_rx_buf, rx_size, NULL,
+			    PACKET_TIMEOUT);
 }
 
 static int vmk80xx_read_packet(struct comedi_device *dev)
@@ -183,10 +186,8 @@ static int vmk80xx_read_packet(struct comedi_device *dev)
 	struct usb_endpoint_descriptor *ep;
 	unsigned int pipe;
 
-	if (devpriv->model == VMK8061_MODEL) {
-		vmk80xx_do_bulk_msg(dev);
-		return 0;
-	}
+	if (devpriv->model == VMK8061_MODEL)
+		return vmk80xx_do_bulk_msg(dev);
 
 	ep = devpriv->ep_rx;
 	pipe = usb_rcvintpipe(usb, ep->bEndpointAddress);
@@ -204,10 +205,8 @@ static int vmk80xx_write_packet(struct comedi_device *dev, int cmd)
 
 	devpriv->usb_tx_buf[0] = cmd;
 
-	if (devpriv->model == VMK8061_MODEL) {
-		vmk80xx_do_bulk_msg(dev);
-		return 0;
-	}
+	if (devpriv->model == VMK8061_MODEL)
+		return vmk80xx_do_bulk_msg(dev);
 
 	ep = devpriv->ep_tx;
 	pipe = usb_sndintpipe(usb, ep->bEndpointAddress);

-- 
2.56.0