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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2021-02-03 13:37:02 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-02-03 13:14:45 +0100 |
| commit | d4a610635400ccc382792f6be69427078541c678 (patch) | |
| tree | c7a11e18f8862b084d6cf7e5761f1bc0e0d22ea7 /drivers/usb | |
| parent | 3241929b67d28c83945d3191c6816a3271fd6b85 (diff) | |
| download | lwn-d4a610635400ccc382792f6be69427078541c678.tar.gz lwn-d4a610635400ccc382792f6be69427078541c678.zip | |
xhci: fix bounce buffer usage for non-sg list case
xhci driver may in some special cases need to copy small amounts
of payload data to a bounce buffer in order to meet the boundary
and alignment restrictions set by the xHCI specification.
In the majority of these cases the data is in a sg list, and
driver incorrectly assumed data is always in urb->sg when using
the bounce buffer.
If data instead is contiguous, and in urb->transfer_buffer, we may still
need to bounce buffer a small part if data starts very close (less than
packet size) to a 64k boundary.
Check if sg list is used before copying data to/from it.
Fixes: f9c589e142d0 ("xhci: TD-fragment, align the unsplittable case with a bounce buffer")
Cc: stable@vger.kernel.org
Reported-by: Andreas Hartmann <andihartmann@01019freenet.de>
Tested-by: Andreas Hartmann <andihartmann@01019freenet.de>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210203113702.436762-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/host/xhci-ring.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index cf0c93a90200..89c3be9917f6 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -699,11 +699,16 @@ static void xhci_unmap_td_bounce_buffer(struct xhci_hcd *xhci, dma_unmap_single(dev, seg->bounce_dma, ring->bounce_buf_len, DMA_FROM_DEVICE); /* for in tranfers we need to copy the data from bounce to sg */ - len = sg_pcopy_from_buffer(urb->sg, urb->num_sgs, seg->bounce_buf, - seg->bounce_len, seg->bounce_offs); - if (len != seg->bounce_len) - xhci_warn(xhci, "WARN Wrong bounce buffer read length: %zu != %d\n", - len, seg->bounce_len); + if (urb->num_sgs) { + len = sg_pcopy_from_buffer(urb->sg, urb->num_sgs, seg->bounce_buf, + seg->bounce_len, seg->bounce_offs); + if (len != seg->bounce_len) + xhci_warn(xhci, "WARN Wrong bounce buffer read length: %zu != %d\n", + len, seg->bounce_len); + } else { + memcpy(urb->transfer_buffer + seg->bounce_offs, seg->bounce_buf, + seg->bounce_len); + } seg->bounce_len = 0; seg->bounce_offs = 0; } @@ -3277,12 +3282,16 @@ static int xhci_align_td(struct xhci_hcd *xhci, struct urb *urb, u32 enqd_len, /* create a max max_pkt sized bounce buffer pointed to by last trb */ if (usb_urb_dir_out(urb)) { - len = sg_pcopy_to_buffer(urb->sg, urb->num_sgs, - seg->bounce_buf, new_buff_len, enqd_len); - if (len != new_buff_len) - xhci_warn(xhci, - "WARN Wrong bounce buffer write length: %zu != %d\n", - len, new_buff_len); + if (urb->num_sgs) { + len = sg_pcopy_to_buffer(urb->sg, urb->num_sgs, + seg->bounce_buf, new_buff_len, enqd_len); + if (len != new_buff_len) + xhci_warn(xhci, "WARN Wrong bounce buffer write length: %zu != %d\n", + len, new_buff_len); + } else { + memcpy(seg->bounce_buf, urb->transfer_buffer + enqd_len, new_buff_len); + } + seg->bounce_dma = dma_map_single(dev, seg->bounce_buf, max_pkt, DMA_TO_DEVICE); } else { |