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

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <maxime.ripard@bootlin.com>,
	Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel@ffwll.ch>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Ian Abbott <abbotti@mev.co.uk>,
	H Hartley Sweeten <hsweeten@visionengravers.com>,
	devel@driverdev.osuosl.org, linux-s390@vger.kernel.org,
	Intel Linux Wireless <linuxwifi@intel.com>,
	linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
	intel-gfx@lists.freedesktop.org, linux-wireless@vger.kernel.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-mm@kvack.org, iommu@lists.linux-foundation.org,
	"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
	linux-media@vger.kernel.org,
	Chris Wilson <chris@chris-wilson.co.uk>
Subject: Re: [Intel-gfx] [PATCH 03/16] drm/i915: stop using drm_pci_alloc
Date: Fri, 14 Jun 2019 19:45:49 +0300	[thread overview]
Message-ID: <20190614164549.GD5942@intel.com> (raw)
In-Reply-To: <20190614134726.3827-4-hch@lst.de>

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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-- 
Ville Syrjälä
Intel