USB: fix usbmon and DMA mapping for scatter-gather URBs
This patch (as1368) fixes a rather obscure bug in usbmon: When tracing
URBs sent by the scatter-gather library, it accesses the data buffers
while they are still mapped for DMA.
The solution is to move the mapping and unmapping out of the s-g
library and into the usual place in hcd.c. This requires the addition
of new URB flag bits to describe the kind of mapping needed, since we
have to call dma_map_sg() if the HCD supports native scatter-gather
operation and dma_map_page() if it doesn't. The nice thing about
having the new flags is that they simplify the testing for unmapping.
The patch removes the only caller of usb_buffer_[un]map_sg(), so those
functions are #if'ed out. A later patch will remove them entirely.
As a result of this change, urb->sg will be set in situations where
it wasn't set previously. Hence the xhci and whci drivers are
adjusted to test urb->num_sgs instead, which retains its original
meaning and is nonzero only when the HCD has to handle a scatterlist.
Finally, even when a submission error occurs we don't want to hand
URBs to usbmon before they are unmapped. The submission path is
rearranged so that map_urb_for_dma() is called only for non-root-hub
URBs and unmap_urb_for_dma() is called immediately after a submission
error. This simplifies the error handling.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 2532a09..a760e46 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -333,9 +333,12 @@
is_out = usb_endpoint_dir_out(&ep->desc);
}
- /* Cache the direction for later use */
- urb->transfer_flags = (urb->transfer_flags & ~URB_DIR_MASK) |
- (is_out ? URB_DIR_OUT : URB_DIR_IN);
+ /* Clear the internal flags and cache the direction for later use */
+ urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
+ URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
+ URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
+ URB_DMA_SG_COMBINED);
+ urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
dev->state < USB_STATE_CONFIGURED)