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| author | Alan Stern <stern@rowland.harvard.edu> | 2010-04-02 13:27:28 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-20 13:21:37 -0700 |
| commit | ff9c895f07d36193c75533bda8193bde8ca99d02 (patch) | |
| tree | 386ca8e37734c4810e59a55eaba92e4e88275d14 /drivers/usb/core/urb.c | |
| parent | 0ff8d1b3c858ea7c8daa54f7577971a76d04d283 (diff) | |
| download | lwn-ff9c895f07d36193c75533bda8193bde8ca99d02.tar.gz lwn-ff9c895f07d36193c75533bda8193bde8ca99d02.zip | |
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/core/urb.c')
| -rw-r--r-- | drivers/usb/core/urb.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c index 2532a0917f8c..a760e46871c5 100644 --- a/drivers/usb/core/urb.c +++ b/drivers/usb/core/urb.c @@ -333,9 +333,12 @@ int usb_submit_urb(struct urb *urb, gfp_t mem_flags) 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) |