target/linux/generic/pending-4.19/171-usb-dwc2-Fix-inefficient-copy-of-unaligned-buffers.patch

   1 From 81da1738eee68f1961e03bdeb2d60cf0eb4dd713 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Antti=20Sepp=C3=A4l=C3=A4?= <a.seppala@gmail.com>
   3 Date: Thu, 5 Jul 2018 12:06:18 +0300
   4 Subject: [PATCH 2/2] usb: dwc2: Fix inefficient copy of unaligned buffers
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Make sure only to copy any actual data rather than the whole buffer,
  10 when releasing the temporary buffer used for unaligned non-isochronous
  11 transfers.
  12
  13 Taken directly from commit 0efd937e27d5e ("USB: ehci-tegra: fix inefficient
  14 copy of unaligned buffers")
  15
  16 Tested with Lantiq xRX200 (MIPS) and RPi Model B Rev 2 (ARM)
  17
  18 Signed-off-by: Antti Seppälä <a.seppala@gmail.com>
  19 ---
  20  drivers/usb/dwc2/hcd.c | 12 +++++++++---
  21  1 file changed, 9 insertions(+), 3 deletions(-)
  22
  23 --- a/drivers/usb/dwc2/hcd.c
  24 +++ b/drivers/usb/dwc2/hcd.c
  25 @@ -2669,6 +2669,7 @@ static int dwc2_alloc_split_dma_aligned_
  26  static void dwc2_free_dma_aligned_buffer(struct urb *urb)
  27  {
  28         void *stored_xfer_buffer;
  29 +       size_t length;
  30
  31         if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
  32                 return;
  33 @@ -2677,9 +2678,14 @@ static void dwc2_free_dma_aligned_buffer
  34         memcpy(&stored_xfer_buffer, urb->transfer_buffer +
  35                urb->transfer_buffer_length, sizeof(urb->transfer_buffer));
  36
  37 -       if (usb_urb_dir_in(urb))
  38 -               memcpy(stored_xfer_buffer, urb->transfer_buffer,
  39 -                      urb->transfer_buffer_length);
  40 +       if (usb_urb_dir_in(urb)) {
  41 +               if (usb_pipeisoc(urb->pipe))
  42 +                       length = urb->transfer_buffer_length;
  43 +               else
  44 +                       length = urb->actual_length;
  45 +
  46 +               memcpy(stored_xfer_buffer, urb->transfer_buffer, length);
  47 +       }
  48         kfree(urb->transfer_buffer);
  49         urb->transfer_buffer = stored_xfer_buffer;
  50