git.openwrt.org Git - openwrt/staging/nbd.git/blob

   1 From 9dc454ebc4380cd90c24a3c224bb0ac7b3d9cc29 Mon Sep 17 00:00:00 2001
   2 From: Gurchetan Singh <gurchetansingh@chromium.org>
   3 Date: Mon, 2 Dec 2019 17:36:27 -0800
   4 Subject: [PATCH] udmabuf: implement begin_cpu_access/end_cpu_access
   5  hooks
   6
   7 Commit 284562e1f34874e267d4f499362c3816f8f6bc3f upstream.
   8
   9 With the misc device, we should end up using the result of
  10 get_arch_dma_ops(..) or dma-direct ops.
  11
  12 This can allow us to have WC mappings in the guest after
  13 synchronization.
  14
  15 Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
  16 Link: http://patchwork.freedesktop.org/patch/msgid/20191203013627.85991-4-gurchetansingh@chromium.org
  17 Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
  18 ---
  19  drivers/dma-buf/udmabuf.c | 39 +++++++++++++++++++++++++++++++++++++++
  20  1 file changed, 39 insertions(+)
  21
  22 --- a/drivers/dma-buf/udmabuf.c
  23 +++ b/drivers/dma-buf/udmabuf.c
  24 @@ -18,6 +18,7 @@ static const size_t size_limit_mb = 64;
  25  struct udmabuf {
  26         pgoff_t pagecount;
  27         struct page **pages;
  28 +       struct sg_table *sg;
  29         struct miscdevice *device;
  30  };
  31
  32 @@ -98,20 +99,58 @@ static void unmap_udmabuf(struct dma_buf
  33  static void release_udmabuf(struct dma_buf *buf)
  34  {
  35         struct udmabuf *ubuf = buf->priv;
  36 +       struct device *dev = ubuf->device->this_device;
  37         pgoff_t pg;
  38
  39 +       if (ubuf->sg)
  40 +               put_sg_table(dev, ubuf->sg, DMA_BIDIRECTIONAL);
  41 +
  42         for (pg = 0; pg < ubuf->pagecount; pg++)
  43                 put_page(ubuf->pages[pg]);
  44         kfree(ubuf->pages);
  45         kfree(ubuf);
  46  }
  47
  48 +static int begin_cpu_udmabuf(struct dma_buf *buf,
  49 +                            enum dma_data_direction direction)
  50 +{
  51 +       struct udmabuf *ubuf = buf->priv;
  52 +       struct device *dev = ubuf->device->this_device;
  53 +
  54 +       if (!ubuf->sg) {
  55 +               ubuf->sg = get_sg_table(dev, buf, direction);
  56 +               if (IS_ERR(ubuf->sg))
  57 +                       return PTR_ERR(ubuf->sg);
  58 +       } else {
  59 +               dma_sync_sg_for_device(dev, ubuf->sg->sgl,
  60 +                                      ubuf->sg->nents,
  61 +                                      direction);
  62 +       }
  63 +
  64 +       return 0;
  65 +}
  66 +
  67 +static int end_cpu_udmabuf(struct dma_buf *buf,
  68 +                          enum dma_data_direction direction)
  69 +{
  70 +       struct udmabuf *ubuf = buf->priv;
  71 +       struct device *dev = ubuf->device->this_device;
  72 +
  73 +       if (!ubuf->sg)
  74 +               return -EINVAL;
  75 +
  76 +       dma_sync_sg_for_cpu(dev, ubuf->sg->sgl, ubuf->sg->nents, direction);
  77 +       return 0;
  78 +}
  79 +
  80  static const struct dma_buf_ops udmabuf_ops = {
  81         .cache_sgt_mapping = true,
  82         .map_dma_buf       = map_udmabuf,
  83         .unmap_dma_buf     = unmap_udmabuf,
  84         .release           = release_udmabuf,
  85         .mmap              = mmap_udmabuf,
  86 +       .begin_cpu_access  = begin_cpu_udmabuf,
  87 +       .end_cpu_access    = end_cpu_udmabuf,
  88  };
  89
  90  #define SEALS_WANTED (F_SEAL_SHRINK)