[PATCH 4.14 08/65] xhci: Fix false warning message about wrong bounce buffer write length

From: Greg Kroah-Hartman
Date: Wed Oct 16 2019 - 18:12:44 EST

From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>

commit c03101ff4f74bb30679c1a03d551ecbef1024bf6 upstream.

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@xxxxxxxxxxxxxxx> # v4.8+
Fixes: 597c56e372da ("xhci: update bounce buffer with correct sg num")
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1570190373-30684-2-git-send-email-mathias.nyman@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/usb/host/xhci-ring.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3223,10 +3223,10 @@ static int xhci_align_td(struct xhci_hcd
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)
"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 {