netdev - [PATCH 5/6] usb: hso: obey DMA rules in tiocmget

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Date:   Thu,  6 Jun 2019 14:55:47 +0200
From:   Oliver Neukum <oneukum@...e.com>
To:     davem@...emloft.net, netdev@...r.kernel.org
Cc:     Oliver Neukum <oneukum@...e.com>
Subject: [PATCH 5/6] usb: hso: obey DMA rules in tiocmget

The serial state information must not be embedded into another
data structure, as this interferes with cache handling for DMA.
Allocating it separately.

Signed-off-by: Oliver Neukum <oneukum@...e.com>
---
 drivers/net/usb/hso.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index 7379df01cd98..489024f0ae62 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -200,7 +200,7 @@ struct hso_tiocmget {
 	int    intr_completed;
 	struct usb_endpoint_descriptor *endp;
 	struct urb *urb;
-	struct hso_serial_state_notification serial_state_notification;
+	struct hso_serial_state_notification *serial_state_notification;
 	__le16    prev_UART_state_bitmap;
 	struct uart_icount icount;
 };
@@ -1446,7 +1446,7 @@ static int tiocmget_submit_urb(struct hso_serial *serial,
 			 usb_rcvintpipe(usb,
 					tiocmget->endp->
 					bEndpointAddress & 0x7F),
-			 &tiocmget->serial_state_notification,
+			 tiocmget->serial_state_notification,
 			 sizeof(struct hso_serial_state_notification),
 			 tiocmget_intr_callback, serial,
 			 tiocmget->endp->bInterval);
@@ -1493,7 +1493,7 @@ static void tiocmget_intr_callback(struct urb *urb)
 	/* wIndex should be the USB interface number of the port to which the
 	 * notification applies, which should always be the Modem port.
 	 */
-	serial_state_notification = &tiocmget->serial_state_notification;
+	serial_state_notification = tiocmget->serial_state_notification;
 	if (serial_state_notification->bmRequestType != BM_REQUEST_TYPE ||
 	    serial_state_notification->bNotification != B_NOTIFICATION ||
 	    le16_to_cpu(serial_state_notification->wValue) != W_VALUE ||
@@ -2578,6 +2578,8 @@ static void hso_free_tiomget(struct hso_serial *serial)
 		usb_free_urb(tiocmget->urb);
 		tiocmget->urb = NULL;
 		serial->tiocmget = NULL;
+		kfree(tiocmget->serial_state_notification);
+		tiocmget->serial_state_notification = NULL;
 		kfree(tiocmget);
 	}
 }
@@ -2628,10 +2630,13 @@ static struct hso_device *hso_create_bulk_serial_device(
 		num_urbs = 2;
 		serial->tiocmget = kzalloc(sizeof(struct hso_tiocmget),
 					   GFP_KERNEL);
+		serial->tiocmget->serial_state_notification
+		      	= kzalloc(sizeof(struct hso_serial_state_notification),
+					   GFP_KERNEL);
 		/* it isn't going to break our heart if serial->tiocmget
 		 *  allocation fails don't bother checking this.
 		 */
-		if (serial->tiocmget) {
+		if (serial->tiocmget && serial->tiocmget->serial_state_notification) {
 			tiocmget = serial->tiocmget;
 			tiocmget->urb = usb_alloc_urb(0, GFP_KERNEL);
 			if (tiocmget->urb) {
-- 
2.16.4