src/patches/linux/linux-4.14-Revert-usb-dwc2-Fix-DMA-alignment.patch

   1 From a44147a09baf8c46cc0b02332df3a4656e0659d5 Mon Sep 17 00:00:00 2001
   2 From: Arne Fitzenreiter <arne_f@ipfire.org>
   3 Date: Mon, 10 Dec 2018 13:12:00 +0100
   4 Subject: [PATCH] Revert "usb: dwc2: Fix DMA alignment to start at allocated
   5  boundary"
   6
   7 This reverts commit 68fc92a0f3913d539d1ac68a861f895e34099e46.
   8 ---
   9  drivers/usb/dwc2/hcd.c | 44 +++++++++++++++++++++-----------------------
  10  1 file changed, 21 insertions(+), 23 deletions(-)
  11
  12 diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
  13 index fa20ec4..4b81d08 100644
  14 --- a/drivers/usb/dwc2/hcd.c
  15 +++ b/drivers/usb/dwc2/hcd.c
  16 @@ -2644,29 +2644,34 @@ static int dwc2_alloc_split_dma_aligned_buf(struct dwc2_hsotg *hsotg,
  17
  18  #define DWC2_USB_DMA_ALIGN 4
  19
  20 +struct dma_aligned_buffer {
  21 +       void *kmalloc_ptr;
  22 +       void *old_xfer_buffer;
  23 +       u8 data[0];
  24 +};
  25 +
  26  static void dwc2_free_dma_aligned_buffer(struct urb *urb)
  27  {
  28 -       void *stored_xfer_buffer;
  29 +       struct dma_aligned_buffer *temp;
  30
  31         if (!(urb->transfer_flags & URB_ALIGNED_TEMP_BUFFER))
  32                 return;
  33
  34 -       /* Restore urb->transfer_buffer from the end of the allocated area */
  35 -       memcpy(&stored_xfer_buffer, urb->transfer_buffer +
  36 -              urb->transfer_buffer_length, sizeof(urb->transfer_buffer));
  37 +       temp = container_of(urb->transfer_buffer,
  38 +                           struct dma_aligned_buffer, data);
  39
  40         if (usb_urb_dir_in(urb))
  41 -               memcpy(stored_xfer_buffer, urb->transfer_buffer,
  42 +               memcpy(temp->old_xfer_buffer, temp->data,
  43                        urb->transfer_buffer_length);
  44 -       kfree(urb->transfer_buffer);
  45 -       urb->transfer_buffer = stored_xfer_buffer;
  46 +       urb->transfer_buffer = temp->old_xfer_buffer;
  47 +       kfree(temp->kmalloc_ptr);
  48
  49         urb->transfer_flags &= ~URB_ALIGNED_TEMP_BUFFER;
  50  }
  51
  52  static int dwc2_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
  53  {
  54 -       void *kmalloc_ptr;
  55 +       struct dma_aligned_buffer *temp, *kmalloc_ptr;
  56         size_t kmalloc_size;
  57
  58         if (urb->num_sgs || urb->sg ||
  59 @@ -2674,29 +2679,22 @@ static int dwc2_alloc_dma_aligned_buffer(struct urb *urb, gfp_t mem_flags)
  60             !((uintptr_t)urb->transfer_buffer & (DWC2_USB_DMA_ALIGN - 1)))
  61                 return 0;
  62
  63 -       /*
  64 -        * Allocate a buffer with enough padding for original transfer_buffer
  65 -        * pointer. This allocation is guaranteed to be aligned properly for
  66 -        * DMA
  67 -        */
  68 +       /* Allocate a buffer with enough padding for alignment */
  69         kmalloc_size = urb->transfer_buffer_length +
  70 -               sizeof(urb->transfer_buffer);
  71 +               sizeof(struct dma_aligned_buffer) + DWC2_USB_DMA_ALIGN - 1;
  72
  73         kmalloc_ptr = kmalloc(kmalloc_size, mem_flags);
  74         if (!kmalloc_ptr)
  75                 return -ENOMEM;
  76
  77 -       /*
  78 -        * Position value of original urb->transfer_buffer pointer to the end
  79 -        * of allocation for later referencing
  80 -        */
  81 -       memcpy(kmalloc_ptr + urb->transfer_buffer_length,
  82 -              &urb->transfer_buffer, sizeof(urb->transfer_buffer));
  83 -
  84 +       /* Position our struct dma_aligned_buffer such that data is aligned */
  85 +       temp = PTR_ALIGN(kmalloc_ptr + 1, DWC2_USB_DMA_ALIGN) - 1;
  86 +       temp->kmalloc_ptr = kmalloc_ptr;
  87 +       temp->old_xfer_buffer = urb->transfer_buffer;
  88         if (usb_urb_dir_out(urb))
  89 -               memcpy(kmalloc_ptr, urb->transfer_buffer,
  90 +               memcpy(temp->data, urb->transfer_buffer,
  91                        urb->transfer_buffer_length);
  92 -       urb->transfer_buffer = kmalloc_ptr;
  93 +       urb->transfer_buffer = temp->data;
  94
  95         urb->transfer_flags |= URB_ALIGNED_TEMP_BUFFER;
  96
  97 --
  98 2.7.4
  99