The check printing out the "WARN Wrong bounce buffer write length:" uses incorrect values when comparing bytes written from scatterlist to bounce buffer. Actual copied lengths are fine.

The used seg->bounce_len will be set to equal new_buf_len a few lines later in the code, but is incorrect when doing the comparison.

The patch which added this false warning was backported to 4.8+ kernels so this should be backported as far as well.

Cc: stable@vger.kernel.org # v4.8+ Fixes: 597c56e372da ("xhci: update bounce buffer with correct sg num") Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com --- drivers/usb/host/xhci-ring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 9741cdeea9d7..85ceb43e3405 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3202,10 +3202,10 @@ static int xhci_align_td(struct xhci_hcd *xhci, struct urb *urb, u32 enqd_len, 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 != seg->bounce_len) + if (len != new_buff_len) xhci_warn(xhci, "WARN Wrong bounce buffer write length: %zu != %d\n", - len, seg->bounce_len); + len, new_buff_len); seg->bounce_dma = dma_map_single(dev, seg->bounce_buf, max_pkt, DMA_TO_DEVICE); } else {