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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/mon
parent0ff8d1b3c858ea7c8daa54f7577971a76d04d283 (diff)
downloadlinux-ff9c895f07d36193c75533bda8193bde8ca99d02.tar.bz2
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/mon')
-rw-r--r--drivers/usb/mon/mon_bin.c2
-rw-r--r--drivers/usb/mon/mon_text.c4
2 files changed, 2 insertions, 4 deletions
diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index ddf7f9a1b336..8a7968df278f 100644
--- a/drivers/usb/mon/mon_bin.c
+++ b/drivers/usb/mon/mon_bin.c
@@ -416,7 +416,7 @@ static unsigned int mon_bin_get_data(const struct mon_reader_bin *rp,
} else {
/* If IOMMU coalescing occurred, we cannot trust sg_page */
- if (urb->sg->nents != urb->num_sgs) {
+ if (urb->transfer_flags & URB_DMA_SG_COMBINED) {
*flag = 'D';
return length;
}
diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
index 4d0be130f49b..d56260280f54 100644
--- a/drivers/usb/mon/mon_text.c
+++ b/drivers/usb/mon/mon_text.c
@@ -161,9 +161,7 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
} else {
struct scatterlist *sg = urb->sg->sg;
- /* If IOMMU coalescing occurred, we cannot trust sg_page */
- if (urb->sg->nents != urb->num_sgs ||
- PageHighMem(sg_page(sg)))
+ if (PageHighMem(sg_page(sg)))
return 'D';
/* For the text interface we copy only the first sg buffer */