RE: [PATCH V3 1/4] misc: vop: change the way of allocating vring and device page

Sherry Sun
2020-10-26T02:54:48Z

Hi Christoph,

>
> > static int mic_dp_init(struct mic_device *mdev) {
> > - mdev->dp = kzalloc(MIC_DP_SIZE, GFP_KERNEL);
> > + mdev->dp = dma_alloc_coherent(&mdev->pdev->dev, MIC_DP_SIZE,
> > + &mdev->dp_dma_addr, GFP_KERNEL);
> > if (!mdev->dp)
> > return -ENOMEM;
> >
> > - mdev->dp_dma_addr = mic_map_single(mdev,
> > - mdev->dp, MIC_DP_SIZE);
> > - if (mic_map_error(mdev->dp_dma_addr)) {
> > - kfree(mdev->dp);
> > - dev_err(&mdev->pdev->dev, "%s %d err %d\n",
> > - __func__, __LINE__, -ENOMEM);
> > - return -ENOMEM;
> > - }
> > mdev->ops->write_spad(mdev, MIC_DPLO_SPAD, mdev-
> >dp_dma_addr);
> > mdev->ops->write_spad(mdev, MIC_DPHI_SPAD, mdev-
> >dp_dma_addr >> 32);
> > return 0;
> > @@ -68,8 +62,7 @@ static int mic_dp_init(struct mic_device *mdev)
> > /* Uninitialize the device page */
> > static void mic_dp_uninit(struct mic_device *mdev) {
> > - mic_unmap_single(mdev, mdev->dp_dma_addr, MIC_DP_SIZE);
> > - kfree(mdev->dp);
> > + dma_free_coherent(&mdev->pdev->dev, MIC_DP_SIZE, mdev->dp,
> > +mdev->dp_dma_addr);
> > }
>
> This adds an over 80 char line. Also please just kill mic_dp_init and
> mic_dp_uninit and inline those into the callers.

Okay, will fix them.
>
> > + vvr->buf = dma_alloc_coherent(vop_dev(vdev),
> VOP_INT_DMA_BUF_SIZE,
> > + &vvr->buf_da, GFP_KERNEL);
>
> Another overly long line.
>
> > @@ -1068,7 +1049,7 @@ vop_query_offset(struct vop_vdev *vdev,
> unsigned long offset,
> > struct vop_vringh *vvr = &vdev->vvr[i];
> >
> > if (offset == start) {
> > - *pa = virt_to_phys(vvr->vring.va);
> > + *pa = vqconfig[i].address;
>
> vqconfig[i].address is a __le64, so this needs an endian swap.
>
> But more importantly the caller of vop_query_offset, vop_mmap, uses
> remap_pfn_range and pa. You cannot mix remap_pfn_range with DMA
> coherent allocations, it can only be mmaped using dma_mmap_coherent.

Will change to use dma_mmap_coherent in V4.

Best regards
Sherry