Re: [Intel-gfx] [PATCH 03/16] drm/i915: stop using drm_pci_alloc

Ville Syrjälä
2019-06-14T16:45:49Z

On Fri, Jun 14, 2019 at 03:47:13PM +0200, Christoph Hellwig wrote:
> Remove usage of the legacy drm PCI DMA wrappers, and with that the
> incorrect usage cocktail of __GFP_COMP, virt_to_page on DMA allocation
> and SetPageReserved.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> drivers/gpu/drm/i915/i915_gem.c | 30 +++++++++++++-------------
> drivers/gpu/drm/i915/i915_gem_object.h | 3 ++-
> drivers/gpu/drm/i915/intel_display.c | 2 +-
> 3 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index ad01c92aaf74..8f2053c91aff 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -228,7 +228,6 @@ i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
> static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
> {
> struct address_space *mapping = obj->base.filp->f_mapping;
> - drm_dma_handle_t *phys;
> struct sg_table *st;
> struct scatterlist *sg;
> char *vaddr;
> @@ -242,13 +241,13 @@ static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
> * to handle all possible callers, and given typical object sizes,
> * the alignment of the buddy allocation will naturally match.
> */
> - phys = drm_pci_alloc(obj->base.dev,
> - roundup_pow_of_two(obj->base.size),
> - roundup_pow_of_two(obj->base.size));
> - if (!phys)
> + obj->phys_vaddr = dma_alloc_coherent(&obj->base.dev->pdev->dev,
> + roundup_pow_of_two(obj->base.size),
> + &obj->phys_handle, GFP_KERNEL);
> + if (!obj->phys_vaddr)
> return -ENOMEM;
>
> - vaddr = phys->vaddr;
> + vaddr = obj->phys_vaddr;
> for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
> struct page *page;
> char *src;
> @@ -286,18 +285,17 @@ static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
> sg->offset = 0;
> sg->length = obj->base.size;
>
> - sg_dma_address(sg) = phys->busaddr;
> + sg_dma_address(sg) = obj->phys_handle;
> sg_dma_len(sg) = obj->base.size;
>
> - obj->phys_handle = phys;
> -
> __i915_gem_object_set_pages(obj, st, sg->length);
>
> return 0;
>
> err_phys:
> - drm_pci_free(obj->base.dev, phys);
> -
> + dma_free_coherent(&obj->base.dev->pdev->dev,
> + roundup_pow_of_two(obj->base.size), obj->phys_vaddr,
> + obj->phys_handle);

Need to undo the damage to obj->phys_vaddr here since
i915_gem_pwrite_ioctl() will now use that to determine if it's
dealing with a phys obj.

> return err;
> }
>
> @@ -335,7 +333,7 @@ i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
>
> if (obj->mm.dirty) {
> struct address_space *mapping = obj->base.filp->f_mapping;
> - char *vaddr = obj->phys_handle->vaddr;
> + char *vaddr = obj->phys_vaddr;
> int i;
>
> for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
> @@ -363,7 +361,9 @@ i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,
> sg_free_table(pages);
> kfree(pages);
>
> - drm_pci_free(obj->base.dev, obj->phys_handle);
> + dma_free_coherent(&obj->base.dev->pdev->dev,
> + roundup_pow_of_two(obj->base.size), obj->phys_vaddr,
> + obj->phys_handle);

This one is fine I think since the object remains a phys obj once
turned into one. At least the current code isn't clearing
phys_handle here. But my memory is a bit hazy on the details. Chris?

Also maybe s/phys_handle/phys_busaddr/ all over?

> }
>
> static void
> @@ -603,7 +603,7 @@ i915_gem_phys_pwrite(struct drm_i915_gem_object *obj,
> struct drm_i915_gem_pwrite *args,
> struct drm_file *file)
> {
> - void *vaddr = obj->phys_handle->vaddr + args->offset;
> + void *vaddr = obj->phys_vaddr + args->offset;
> char __user *user_data = u64_to_user_ptr(args->data_ptr);
>
> /* We manually control the domain here and pretend that it
> @@ -1431,7 +1431,7 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
> ret = i915_gem_gtt_pwrite_fast(obj, args);
>
> if (ret == -EFAULT || ret == -ENOSPC) {
> - if (obj->phys_handle)
> + if (obj->phys_vaddr)
> ret = i915_gem_phys_pwrite(obj, args, file);
> else
> ret = i915_gem_shmem_pwrite(obj, args);
> diff --git a/drivers/gpu/drm/i915/i915_gem_object.h b/drivers/gpu/drm/i915/i915_gem_object.h
> index ca93a40c0c87..14bd2d61d0f6 100644
> --- a/drivers/gpu/drm/i915/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/i915_gem_object.h
> @@ -290,7 +290,8 @@ struct drm_i915_gem_object {
> };
>
> /** for phys allocated objects */
> - struct drm_dma_handle *phys_handle;
> + dma_addr_t phys_handle;
> + void *phys_vaddr;
>
> struct reservation_object __builtin_resv;
> };
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 5098228f1302..4f8b368ac4e2 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -10066,7 +10066,7 @@ static u32 intel_cursor_base(const struct intel_plane_state *plane_state)
> u32 base;
>
> if (INTEL_INFO(dev_priv)->display.cursor_needs_physical)
> - base = obj->phys_handle->busaddr;
> + base = obj->phys_handle;
> else
> base = intel_plane_ggtt_offset(plane_state);
>
> --
> 2.20.1
>
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> Intel-gfx@lists.freedesktop.org
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--
Ville Syrjälä
Intel