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authorAlan Stern <stern@rowland.harvard.edu>2010-04-02 13:27:28 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2010-05-20 13:21:37 -0700
commitff9c895f07d36193c75533bda8193bde8ca99d02 (patch)
tree386ca8e37734c4810e59a55eaba92e4e88275d14 /drivers/usb/host/whci
parent0ff8d1b3c858ea7c8daa54f7577971a76d04d283 (diff)
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>
Diffstat (limited to 'drivers/usb/host/whci')
-rw-r--r--drivers/usb/host/whci/qset.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/host/whci/qset.c b/drivers/usb/host/whci/qset.c
index 141d049beb3e..b388dd1fb4c4 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);