From: Alan Stern Date: Fri, 2 Apr 2010 17:27:28 +0000 (-0400) Subject: USB: fix usbmon and DMA mapping for scatter-gather URBs X-Git-Tag: v2.6.35-rc1~471^2~155 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff9c895f07d36193c75533bda8193bde8ca99d02;p=pandora-kernel.git 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 CC: Signed-off-by: Greg Kroah-Hartman --- Reading git-diff-tree failed