usb: catch attempts to submit urbs with a vmalloc'd transfer buffer

Save someone else the debug cycles of figuring out why a driver's
transfer request is failing or causing undefined system behavior.
Buffers submitted for dma must come from GFP allocated / DMA-able
memory.

Return -EAGAIN matching the return value for dma_mapping_error() cases.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 9c4e292..adddc66 100644 (file)
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1502,6 +1502,9 @@ int usb_hcd_map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb,
                                        ret = -EAGAIN;
                                else
                                        urb->transfer_flags |= URB_DMA_MAP_PAGE;
+                       } else if (is_vmalloc_addr(urb->transfer_buffer)) {
+                               WARN_ONCE(1, "transfer buffer not dma capable\n");
+                               ret = -EAGAIN;
                        } else {
                                urb->transfer_dma = dma_map_single(
                                                hcd->self.controller,