On Thu, Oct 31, 2019 at 09:29:56AM +0100, Janusz Krzysztofik wrote:
> We need dmabuf specific pwrite() callback utilizing dma-buf API,
> otherwise GEM_PWRITE IOCTL will no longer work with dma-buf backed
> (i.e., PRIME imported) objects on hardware with no mappable aperture.
>
> Signed-off-by: Janusz Krzysztofik <[email protected]>
> Cc: Daniele Ceraolo Spurio <[email protected]>
> Cc: Michal Wajdeczko <[email protected]>
Do we have userspace for this (aside from igts)? Specifically for the
gen12 + dma-buf import + pwrite/read/whatever case you're fixing in this
series here.
-Daniel
> ---
> drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 55 ++++++++++++++++++++++
> 1 file changed, 55 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> index 96ce95c8ac5a..93eea1031c82 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
> @@ -248,9 +248,64 @@ static void i915_gem_object_put_pages_dmabuf(struct
> drm_i915_gem_object *obj,
> DMA_BIDIRECTIONAL);
> }
>
> +static int i915_gem_object_pwrite_dmabuf(struct drm_i915_gem_object *obj,
> + const struct drm_i915_gem_pwrite *args)
> +{
> + struct dma_buf *dmabuf = obj->base.import_attach->dmabuf;
> + void __user *user_data = u64_to_user_ptr(args->data_ptr);
> + struct file *file = dmabuf->file;
> + const struct file_operations *fop = file->f_op;
> + void __force *vaddr;
> + int ret;
> +
> + if (fop->write) {
> + loff_t offset = args->offset;
> +
> + /*
> + * fop->write() is supposed to call dma_buf_begin_cpu_access()
> + * if O_SYNC flag is set, avoid calling it twice
> + */
> + if (!(file->f_flags & O_SYNC)) {
> + ret = dma_buf_begin_cpu_access(dmabuf, DMA_TO_DEVICE);
> + if (ret)
> + return ret;
> + }
> +
> + ret = fop->write(file, user_data, args->size, &offset);
> +
> + if (!(file->f_flags & O_SYNC))
> + dma_buf_end_cpu_access(dmabuf, DMA_TO_DEVICE);
> +
> + if (!ret)
> + return 0;
> + }
> +
> + /* dma-buf file .write() not supported or failed, try dma_buf_vmap() */
> + ret = dma_buf_begin_cpu_access(dmabuf, DMA_TO_DEVICE);
> + if (ret)
> + return ret;
> +
> + vaddr = dma_buf_vmap(dmabuf);
> + if (!vaddr)
> + goto out_err;
> +
> + ret = copy_from_user(vaddr + args->offset, user_data, args->size);
> + dma_buf_vunmap(dmabuf, vaddr);
> + if (!ret)
> + goto out_end;
> +
> +out_err:
> + /* fall back to GTT mapping */
> + ret = -ENODEV;
> +out_end:
> + dma_buf_end_cpu_access(dmabuf, DMA_TO_DEVICE);
> + return ret;
> +}
> +
> static const struct drm_i915_gem_object_ops i915_gem_object_dmabuf_ops = {
> .get_pages = i915_gem_object_get_pages_dmabuf,
> .put_pages = i915_gem_object_put_pages_dmabuf,
> + .pwrite = i915_gem_object_pwrite_dmabuf,
> };
>
> struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,
> --
> 2.21.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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