Commit 63dc6e63 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

Revert "drm/vgem: fix cache synchronization on arm/arm64" 



commit 7e9e5ead ("drm/vgem: fix cache synchronization on arm/arm64")
broke all of the !llc i915-vgem coherency tests in CI, and left the HW
very, very unhappy (which is even more scary).

Fixes: 7e9e5ead ("drm/vgem: fix cache synchronization on arm/arm64")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <robdclark@chromium.org>
Cc: Sean Paul <seanpaul@chromium.org>
Acked-by: default avatarSean Paul <sean@poorly.run>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190801124458.24949-1-chris@chris-wilson.co.uk
parent 5fd5d2b7

drivers/gpu/drm/vgem/vgem_drv.c

+47 −83
Original line number Diff line number Diff line
@@ -47,16 +47,10 @@ static struct vgem_device { 
	struct platform_device *platform;

} *vgem_device;



static void sync_and_unpin(struct drm_vgem_gem_object *bo);

static struct page **pin_and_sync(struct drm_vgem_gem_object *bo);



static void vgem_gem_free_object(struct drm_gem_object *obj)

{

	struct drm_vgem_gem_object *vgem_obj = to_vgem_bo(obj);



	if (!obj->import_attach)

		sync_and_unpin(vgem_obj);



	kvfree(vgem_obj->pages);

	mutex_destroy(&vgem_obj->pages_lock);
@@ -84,15 +78,40 @@ static vm_fault_t vgem_gem_fault(struct vm_fault *vmf) 
		return VM_FAULT_SIGBUS;



	mutex_lock(&obj->pages_lock);

	if (!obj->pages)

		pin_and_sync(obj);

	if (obj->pages) {

		get_page(obj->pages[page_offset]);

		vmf->page = obj->pages[page_offset];

		ret = 0;

	}

	mutex_unlock(&obj->pages_lock);

	if (ret) {

		struct page *page;



		page = shmem_read_mapping_page(

					file_inode(obj->base.filp)->i_mapping,

					page_offset);

		if (!IS_ERR(page)) {

			vmf->page = page;

			ret = 0;

		} else switch (PTR_ERR(page)) {

			case -ENOSPC:

			case -ENOMEM:

				ret = VM_FAULT_OOM;

				break;

			case -EBUSY:

				ret = VM_FAULT_RETRY;

				break;

			case -EFAULT:

			case -EINVAL:

				ret = VM_FAULT_SIGBUS;

				break;

			default:

				WARN_ON(PTR_ERR(page));

				ret = VM_FAULT_SIGBUS;

				break;

		}



	}

	return ret;

}
@@ -258,33 +277,11 @@ static const struct file_operations vgem_driver_fops = { 
	.release	= drm_release,

};



/* Called under pages_lock, except in free path (where it can't race): */

static void sync_and_unpin(struct drm_vgem_gem_object *bo)

{

	struct drm_device *dev = bo->base.dev;



	if (bo->table) {

		dma_sync_sg_for_cpu(dev->dev, bo->table->sgl,

				bo->table->nents, DMA_BIDIRECTIONAL);

		sg_free_table(bo->table);

		kfree(bo->table);

		bo->table = NULL;

	}



	if (bo->pages) {

		drm_gem_put_pages(&bo->base, bo->pages, true, true);

		bo->pages = NULL;

	}

}



static struct page **pin_and_sync(struct drm_vgem_gem_object *bo)

static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)

{

	struct drm_device *dev = bo->base.dev;

	int npages = bo->base.size >> PAGE_SHIFT;

	mutex_lock(&bo->pages_lock);

	if (bo->pages_pin_count++ == 0) {

		struct page **pages;

	struct sg_table *sgt;



	WARN_ON(!mutex_is_locked(&bo->pages_lock));



		pages = drm_gem_get_pages(&bo->base);

		if (IS_ERR(pages)) {
@@ -293,58 +290,19 @@ static struct page **pin_and_sync(struct drm_vgem_gem_object *bo) 
			return pages;

		}



	sgt = drm_prime_pages_to_sg(pages, npages);

	if (IS_ERR(sgt)) {

		dev_err(dev->dev,

			"failed to allocate sgt: %ld\n",

			PTR_ERR(bo->table));

		drm_gem_put_pages(&bo->base, pages, false, false);

		mutex_unlock(&bo->pages_lock);

		return ERR_CAST(bo->table);

	}



	/*

	 * Flush the object from the CPU cache so that importers

	 * can rely on coherent indirect access via the exported

	 * dma-address.

	 */

	dma_sync_sg_for_device(dev->dev, sgt->sgl,

			sgt->nents, DMA_BIDIRECTIONAL);



		bo->pages = pages;

	bo->table = sgt;



	return pages;

}



static struct page **vgem_pin_pages(struct drm_vgem_gem_object *bo)

{

	struct page **pages;



	mutex_lock(&bo->pages_lock);

	if (bo->pages_pin_count++ == 0 && !bo->pages) {

		pages = pin_and_sync(bo);

	} else {

		WARN_ON(!bo->pages);

		pages = bo->pages;

	}

	mutex_unlock(&bo->pages_lock);



	return pages;

	return bo->pages;

}



static void vgem_unpin_pages(struct drm_vgem_gem_object *bo)

{

	/*

	 * We shouldn't hit this for imported bo's.. in the import

	 * case we don't own the scatter-table

	 */

	WARN_ON(bo->base.import_attach);



	mutex_lock(&bo->pages_lock);

	if (--bo->pages_pin_count == 0) {

		WARN_ON(!bo->table);

		sync_and_unpin(bo);

		drm_gem_put_pages(&bo->base, bo->pages, true, true);

		bo->pages = NULL;

	}

	mutex_unlock(&bo->pages_lock);

}
@@ -352,12 +310,18 @@ static void vgem_unpin_pages(struct drm_vgem_gem_object *bo) 
static int vgem_prime_pin(struct drm_gem_object *obj)

{

	struct drm_vgem_gem_object *bo = to_vgem_bo(obj);

	long n_pages = obj->size >> PAGE_SHIFT;

	struct page **pages;



	pages = vgem_pin_pages(bo);

	if (IS_ERR(pages))

		return PTR_ERR(pages);



	/* Flush the object from the CPU cache so that importers can rely

	 * on coherent indirect access via the exported dma-address.

	 */

	drm_clflush_pages(pages, n_pages);



	return 0;

}

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