| Message ID | 1428400012-7563-3-git-send-email-johan@kernel.org |
|---|---|
| State | Deferred |
| Headers | show |
On Tue, 7 Apr 2015, Johan Hovold wrote: > Make sure only to copy any actual data rather than the whole buffer, > when releasing the temporary buffer used for unaligned transfer buffers. > > Note that the corresponding fix of musb also fixes a lockup on > disconnect, where repeated failed transfers would starve the hub > workqueue from processing the disconnect, which would have prevented the > urbs from being resubmitted. In this case there is no data to forward, > but the full buffer length was being copied nonetheless. This is wrong for isochronous transfers, because the transfer data generally isn't contiguous in memory. It would be okay to do this for other transfer types, though. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Apr 07, 2015 at 11:30:15AM -0400, Alan Stern wrote: > On Tue, 7 Apr 2015, Johan Hovold wrote: > > > Make sure only to copy any actual data rather than the whole buffer, > > when releasing the temporary buffer used for unaligned transfer buffers. > > > > Note that the corresponding fix of musb also fixes a lockup on > > disconnect, where repeated failed transfers would starve the hub > > workqueue from processing the disconnect, which would have prevented the > > urbs from being resubmitted. In this case there is no data to forward, > > but the full buffer length was being copied nonetheless. > > This is wrong for isochronous transfers, because the transfer data > generally isn't contiguous in memory. > > It would be okay to do this for other transfer types, though. Thanks for pointing that out. I'll re-spin the series tomorrow. Johan -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c index ff9af29b4e9f..dfe2a7abc36d 100644 --- a/drivers/usb/host/ehci-tegra.c +++ b/drivers/usb/host/ehci-tegra.c @@ -313,7 +313,7 @@ static void free_dma_aligned_buffer(struct urb *urb) if (usb_urb_dir_in(urb)) memcpy(temp->old_xfer_buffer, temp->data, - urb->transfer_buffer_length); + urb->actual_length); urb->transfer_buffer = temp->old_xfer_buffer; kfree(temp->kmalloc_ptr);
Make sure only to copy any actual data rather than the whole buffer, when releasing the temporary buffer used for unaligned transfer buffers. Note that the corresponding fix of musb also fixes a lockup on disconnect, where repeated failed transfers would starve the hub workqueue from processing the disconnect, which would have prevented the urbs from being resubmitted. In this case there is no data to forward, but the full buffer length was being copied nonetheless. Compile-tested only. Fixes: fbf9865c6d96 ("USB: ehci: tegra: Align DMA transfers to 32 bytes") Cc: stable <stable@vger.kernel.org> # v2.6.39 Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/host/ehci-tegra.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)