From ff9c895f07d36193c75533bda8193bde8ca99d02 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 2 Apr 2010 13:27:28 -0400 Subject: 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 CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/whci/qset.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/usb/host/whci') diff --git a/drivers/usb/host/whci/qset.c b/drivers/usb/host/whci/qset.c index 141d049beb3..b388dd1fb4c 100644 --- a/drivers/usb/host/whci/qset.c +++ b/drivers/usb/host/whci/qset.c @@ -646,7 +646,7 @@ int qset_add_urb(struct whc *whc, struct whc_qset *qset, struct urb *urb, wurb->urb = urb; INIT_WORK(&wurb->dequeue_work, urb_dequeue_work); - if (urb->sg) { + if (urb->num_sgs) { ret = qset_add_urb_sg(whc, qset, urb, mem_flags); if (ret == -EINVAL) { qset_free_stds(qset, urb); -- cgit v1.2.3