From ff9c895f07d36193c75533bda8193bde8ca99d02 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Fri, 2 Apr 2010 13:27:28 -0400 Subject: 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 --- drivers/usb/core/message.c | 45 ++++++++++----------------------------------- 1 file changed, 10 insertions(+), 35 deletions(-) (limited to 'drivers/usb/core/message.c') diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c index 619c44f..79d1cdf 100644 --- a/drivers/usb/core/message.c +++ b/drivers/usb/core/message.c @@ -259,9 +259,6 @@ static void sg_clean(struct usb_sg_request *io) kfree(io->urbs); io->urbs = NULL; } - if (io->dev->dev.dma_mask != NULL) - usb_buffer_unmap_sg(io->dev, usb_pipein(io->pipe), - io->sg, io->nents); io->dev = NULL; } @@ -364,7 +361,6 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, { int i; int urb_flags; - int dma; int use_sg; if (!io || !dev || !sg @@ -378,21 +374,9 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, io->pipe = pipe; io->sg = sg; io->nents = nents; - - /* not all host controllers use DMA (like the mainstream pci ones); - * they can use PIO (sl811) or be software over another transport. - */ - dma = (dev->dev.dma_mask != NULL); - if (dma) - io->entries = usb_buffer_map_sg(dev, usb_pipein(pipe), - sg, nents); - else - io->entries = nents; + io->entries = nents; /* initialize all the urbs we'll use */ - if (io->entries <= 0) - return io->entries; - if (dev->bus->sg_tablesize > 0) { io->urbs = kmalloc(sizeof *io->urbs, mem_flags); use_sg = true; @@ -404,8 +388,6 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, goto nomem; urb_flags = 0; - if (dma) - urb_flags |= URB_NO_TRANSFER_DMA_MAP; if (usb_pipein(pipe)) urb_flags |= URB_SHORT_NOT_OK; @@ -423,12 +405,13 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, io->urbs[0]->complete = sg_complete; io->urbs[0]->context = io; + /* A length of zero means transfer the whole sg list */ io->urbs[0]->transfer_buffer_length = length; if (length == 0) { for_each_sg(sg, sg, io->entries, i) { io->urbs[0]->transfer_buffer_length += - sg_dma_len(sg); + sg->length; } } io->urbs[0]->sg = io; @@ -454,26 +437,16 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, io->urbs[i]->context = io; /* - * Some systems need to revert to PIO when DMA is temporarily - * unavailable. For their sakes, both transfer_buffer and - * transfer_dma are set when possible. - * - * Note that if IOMMU coalescing occurred, we cannot - * trust sg_page anymore, so check if S/G list shrunk. + * Some systems can't use DMA; they use PIO instead. + * For their sakes, transfer_buffer is set whenever + * possible. */ - if (io->nents == io->entries && !PageHighMem(sg_page(sg))) + if (!PageHighMem(sg_page(sg))) io->urbs[i]->transfer_buffer = sg_virt(sg); else io->urbs[i]->transfer_buffer = NULL; - if (dma) { - io->urbs[i]->transfer_dma = sg_dma_address(sg); - len = sg_dma_len(sg); - } else { - /* hc may use _only_ transfer_buffer */ - len = sg->length; - } - + len = sg->length; if (length) { len = min_t(unsigned, len, length); length -= len; @@ -481,6 +454,8 @@ int usb_sg_init(struct usb_sg_request *io, struct usb_device *dev, io->entries = i + 1; } io->urbs[i]->transfer_buffer_length = len; + + io->urbs[i]->sg = (struct usb_sg_request *) sg; } io->urbs[--i]->transfer_flags &= ~URB_NO_INTERRUPT; } -- cgit v1.1