USB: uss720: fix DMA-buffer allocation

Make sure the USB control request is allocated separately from
containing structure to prevent potential memory corruption on
non-cache-coherent systems.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c
index e129cf6..40ef40a 100644 (file)
--- a/drivers/usb/misc/uss720.c
+++ b/drivers/usb/misc/uss720.c
@@ -75,7 +75,7 @@ struct uss720_async_request {
        struct list_head asynclist;
        struct completion compl;
        struct urb *urb;
-       struct usb_ctrlrequest dr;
+       struct usb_ctrlrequest *dr;
        __u8 reg[7];
 };
 
@@ -98,6 +98,7 @@ static void destroy_async(struct kref *kref)
 
        if (likely(rq->urb))
                usb_free_urb(rq->urb);
+       kfree(rq->dr);
        spin_lock_irqsave(&priv->asynclock, flags);
        list_del_init(&rq->asynclist);
        spin_unlock_irqrestore(&priv->asynclock, flags);
@@ -120,7 +121,7 @@ static void async_complete(struct urb *urb)
        if (status) {
                dev_err(&urb->dev->dev, "async_complete: urb error %d\n",
                        status);
-       } else if (rq->dr.bRequest == 3) {
+       } else if (rq->dr->bRequest == 3) {
                memcpy(priv->reg, rq->reg, sizeof(priv->reg));
 #if 0
                dev_dbg(&priv->usbdev->dev,
@@ -152,7 +153,7 @@ static struct uss720_async_request *submit_async_request(struct parport_uss720_p
        usbdev = priv->usbdev;
        if (!usbdev)
                return NULL;
-       rq = kmalloc(sizeof(struct uss720_async_request), mem_flags);
+       rq = kzalloc(sizeof(struct uss720_async_request), mem_flags);
        if (!rq) {
                dev_err(&usbdev->dev, "submit_async_request out of memory\n");
                return NULL;
@@ -168,13 +169,18 @@ static struct uss720_async_request *submit_async_request(struct parport_uss720_p
                dev_err(&usbdev->dev, "submit_async_request out of memory\n");
                return NULL;
        }
-       rq->dr.bRequestType = requesttype;
-       rq->dr.bRequest = request;
-       rq->dr.wValue = cpu_to_le16(value);
-       rq->dr.wIndex = cpu_to_le16(index);
-       rq->dr.wLength = cpu_to_le16((request == 3) ? sizeof(rq->reg) : 0);
+       rq->dr = kmalloc(sizeof(*rq->dr), mem_flags);
+       if (!rq->dr) {
+               kref_put(&rq->ref_count, destroy_async);
+               return NULL;
+       }
+       rq->dr->bRequestType = requesttype;
+       rq->dr->bRequest = request;
+       rq->dr->wValue = cpu_to_le16(value);
+       rq->dr->wIndex = cpu_to_le16(index);
+       rq->dr->wLength = cpu_to_le16((request == 3) ? sizeof(rq->reg) : 0);
        usb_fill_control_urb(rq->urb, usbdev, (requesttype & 0x80) ? usb_rcvctrlpipe(usbdev, 0) : usb_sndctrlpipe(usbdev, 0),
-                            (unsigned char *)&rq->dr,
+                            (unsigned char *)rq->dr,
                             (request == 3) ? rq->reg : NULL, (request == 3) ? sizeof(rq->reg) : 0, async_complete, rq);
        /* rq->urb->transfer_flags |= URB_ASYNC_UNLINK; */
        spin_lock_irqsave(&priv->asynclock, flags);