usb/hcd: Ensure scatter-gather is not used for isoc transfers

We don't support sg for isoc transfers, enforce this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 190b1ec7bdcb..bc84106ac057 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1398,7 +1398,15 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
             && !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
                 if (hcd->self.uses_dma) {
                         if (urb->num_sgs) {
-                                int n = dma_map_sg(
+                                int n;
+
+                                /* We don't support sg for isoc transfers ! */
+                                if (usb_endpoint_xfer_isoc(&urb->ep->desc)) {
+                                        WARN_ON(1);
+                                        return -EINVAL;
+                                }
+
+                                n = dma_map_sg(
                                                 hcd->self.controller,
                                                 urb->sg,
                                                 urb->num_sgs,