USB: whci-hcd: correctly handle sg lists longer than QTD_MAX_XFER_SIZE.

When building qTDs (sTDs) from a scatter-gather list, the length of the
qTD must be a multiple of wMaxPacketSize if the transfer continues into
another qTD.

This also fixes a link failure on configurations for 32 bit processors
with 64 bit dma_addr_t (e.g., CONFIG_HIGHMEM_64G).

Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 11 insertions, 11 deletions

diff --git a/drivers/usb/host/whci/qset.c b/drivers/usb/host/whci/qset.c
index 39e855a55c63..7d4204db0f61 100644
--- a/drivers/usb/host/whci/qset.c
+++ b/drivers/usb/host/whci/qset.c
@@ -465,16 +465,16 @@ static int qset_add_urb_sg(struct whc *whc, struct whc_qset *qset, struct urb *u
                          * - the previous one isn't full.
                          *
                          * If a new std is needed but the previous one
-                         * did not end on a wMaxPacketSize boundary
-                         * then this sg list cannot be mapped onto
-                         * multiple qTDs.  Return an error and let the
-                         * caller sort it out.
+                         * was not a whole number of packets then this
+                         * sg list cannot be mapped onto multiple
+                         * qTDs.  Return an error and let the caller
+                         * sort it out.
                          */
                         if (!std
                             || (prev_end & (WHCI_PAGE_SIZE-1))
                             || (dma_addr & (WHCI_PAGE_SIZE-1))
                             || std->len + WHCI_PAGE_SIZE > QTD_MAX_XFER_SIZE) {
-                                if (prev_end % qset->max_packet != 0)
+                                if (std->len % qset->max_packet != 0)
                                         return -EINVAL;
                                 std = qset_new_std(whc, qset, urb, mem_flags);
                                 if (std == NULL) {
@@ -487,14 +487,14 @@ static int qset_add_urb_sg(struct whc *whc, struct whc_qset *qset, struct urb *u
                         dma_len = dma_remaining;
 
                         /*
-                         * If the remainder in this element doesn't
-                         * fit in a single qTD, end the qTD on a
-                         * wMaxPacketSize boundary.
+                         * If the remainder of this element doesn't
+                         * fit in a single qTD, limit the qTD to a
+                         * whole number of packets.  This allows the
+                         * remainder to go into the next qTD.
                          */
                         if (std->len + dma_len > QTD_MAX_XFER_SIZE) {
-                                dma_len = QTD_MAX_XFER_SIZE - std->len;
-                                ep = ((dma_addr + dma_len) / qset->max_packet) * qset->max_packet;
-                                dma_len = ep - dma_addr;
+                                dma_len = (QTD_MAX_XFER_SIZE / qset->max_packet)
+                                        * qset->max_packet - std->len;
                         }
 
                         std->len += dma_len;