Commit a6117097 authored by Maarten Lankhorst's avatar Maarten Lankhorst Committed by Daniel Vetter
Browse files

drm/i915: Rework struct phys attachment handling 



Instead of creating a separate object type, we make changes to
the shmem type, to clear struct page backing. This will allow us to
ensure we never run into a race when we exchange obj->ops with other
function pointers.

Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-9-maarten.lankhorst@linux.intel.com
parent c471748d

drivers/gpu/drm/i915/gem/i915_gem_object.h

+8 −0
Original line number Diff line number Diff line
@@ -37,7 +37,15 @@ void __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj, 
				     struct sg_table *pages,

				     bool needs_clflush);



int i915_gem_object_pwrite_phys(struct drm_i915_gem_object *obj,

				const struct drm_i915_gem_pwrite *args);

int i915_gem_object_pread_phys(struct drm_i915_gem_object *obj,

			       const struct drm_i915_gem_pread *args);



int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align);

void i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,

				    struct sg_table *pages);





void i915_gem_flush_free_objects(struct drm_i915_private *i915);

drivers/gpu/drm/i915/gem/i915_gem_phys.c

+49 −53
Original line number Diff line number Diff line
@@ -76,6 +76,8 @@ static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj) 


	intel_gt_chipset_flush(&to_i915(obj->base.dev)->gt);



	/* We're no longer struct page backed */

	obj->flags &= ~I915_BO_ALLOC_STRUCT_PAGE;

	__i915_gem_object_set_pages(obj, st, sg->length);



	return 0;
@@ -89,7 +91,7 @@ static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj) 
	return -ENOMEM;

}



static void

void

i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj,

			       struct sg_table *pages)

{
@@ -134,8 +136,7 @@ i915_gem_object_put_pages_phys(struct drm_i915_gem_object *obj, 
			  vaddr, dma);

}



static int

phys_pwrite(struct drm_i915_gem_object *obj,

int i915_gem_object_pwrite_phys(struct drm_i915_gem_object *obj,

				const struct drm_i915_gem_pwrite *args)

{

	void *vaddr = sg_page(obj->mm.pages->sgl) + args->offset;
@@ -165,8 +166,7 @@ phys_pwrite(struct drm_i915_gem_object *obj, 
	return 0;

}



static int

phys_pread(struct drm_i915_gem_object *obj,

int i915_gem_object_pread_phys(struct drm_i915_gem_object *obj,

			       const struct drm_i915_gem_pread *args)

{

	void *vaddr = sg_page(obj->mm.pages->sgl) + args->offset;
@@ -186,86 +186,82 @@ phys_pread(struct drm_i915_gem_object *obj, 
	return 0;

}



static void phys_release(struct drm_i915_gem_object *obj)

static int i915_gem_object_shmem_to_phys(struct drm_i915_gem_object *obj)

{

	fput(obj->base.filp);

}

	struct sg_table *pages;

	int err;



static const struct drm_i915_gem_object_ops i915_gem_phys_ops = {

	.name = "i915_gem_object_phys",

	.get_pages = i915_gem_object_get_pages_phys,

	.put_pages = i915_gem_object_put_pages_phys,

	pages = __i915_gem_object_unset_pages(obj);



	err = i915_gem_object_get_pages_phys(obj);

	if (err)

		goto err_xfer;



	.pread  = phys_pread,

	.pwrite = phys_pwrite,

	/* Perma-pin (until release) the physical set of pages */

	__i915_gem_object_pin_pages(obj);



	.release = phys_release,

};

	if (!IS_ERR_OR_NULL(pages))

		i915_gem_shmem_ops.put_pages(obj, pages);



	i915_gem_object_release_memory_region(obj);

	return 0;



err_xfer:

	if (!IS_ERR_OR_NULL(pages)) {

		unsigned int sg_page_sizes = i915_sg_page_sizes(pages->sgl);



		__i915_gem_object_set_pages(obj, pages, sg_page_sizes);

	}

	return err;

}



int i915_gem_object_attach_phys(struct drm_i915_gem_object *obj, int align)

{

	struct sg_table *pages;

	int err;



	if (align > obj->base.size)

		return -EINVAL;



	if (obj->ops == &i915_gem_phys_ops)

		return 0;



	if (!i915_gem_object_is_shmem(obj))

		return -EINVAL;



	if (!i915_gem_object_has_struct_page(obj))

		return 0;



	err = i915_gem_object_unbind(obj, I915_GEM_OBJECT_UNBIND_ACTIVE);

	if (err)

		return err;



	mutex_lock_nested(&obj->mm.lock, I915_MM_GET_PAGES);



	if (unlikely(!i915_gem_object_has_struct_page(obj)))

		goto out;



	if (obj->mm.madv != I915_MADV_WILLNEED) {

		err = -EFAULT;

		goto err_unlock;

		goto out;

	}



	if (i915_gem_object_has_tiling_quirk(obj)) {

		err = -EFAULT;

		goto err_unlock;

		goto out;

	}



	if (obj->mm.mapping) {

	if (obj->mm.mapping || i915_gem_object_has_pinned_pages(obj)) {

		err = -EBUSY;

		goto err_unlock;

		goto out;

	}



	pages = __i915_gem_object_unset_pages(obj);



	obj->ops = &i915_gem_phys_ops;

	obj->flags &= ~I915_BO_ALLOC_STRUCT_PAGE;



	err = ____i915_gem_object_get_pages(obj);

	if (err)

		goto err_xfer;



	/* Perma-pin (until release) the physical set of pages */

	__i915_gem_object_pin_pages(obj);



	if (!IS_ERR_OR_NULL(pages))

		i915_gem_shmem_ops.put_pages(obj, pages);



	i915_gem_object_release_memory_region(obj);



	mutex_unlock(&obj->mm.lock);

	return 0;

	if (unlikely(obj->mm.madv != I915_MADV_WILLNEED)) {

		drm_dbg(obj->base.dev,

			"Attempting to obtain a purgeable object\n");

		err = -EFAULT;

		goto out;

	}



err_xfer:

	obj->ops = &i915_gem_shmem_ops;

	obj->flags |= I915_BO_ALLOC_STRUCT_PAGE;

	if (!IS_ERR_OR_NULL(pages)) {

		unsigned int sg_page_sizes = i915_sg_page_sizes(pages->sgl);

	err = i915_gem_object_shmem_to_phys(obj);



		__i915_gem_object_set_pages(obj, pages, sg_page_sizes);

	}

err_unlock:

out:

	mutex_unlock(&obj->mm.lock);

	return err;

}

drivers/gpu/drm/i915/gem/i915_gem_shmem.c

+21 −1
Original line number Diff line number Diff line
@@ -303,6 +303,11 @@ shmem_put_pages(struct drm_i915_gem_object *obj, struct sg_table *pages) 
	struct pagevec pvec;

	struct page *page;



	if (unlikely(!i915_gem_object_has_struct_page(obj))) {

		i915_gem_object_put_pages_phys(obj, pages);

		return;

	}



	__i915_gem_object_release_shmem(obj, pages, true);



	i915_gem_gtt_finish_pages(obj, pages);
@@ -343,6 +348,9 @@ shmem_pwrite(struct drm_i915_gem_object *obj, 
	/* Caller already validated user args */

	GEM_BUG_ON(!access_ok(user_data, arg->size));



	if (!i915_gem_object_has_struct_page(obj))

		return i915_gem_object_pwrite_phys(obj, arg);



	/*

	 * Before we instantiate/pin the backing store for our use, we

	 * can prepopulate the shmemfs filp efficiently using a write into
@@ -421,8 +429,19 @@ shmem_pwrite(struct drm_i915_gem_object *obj, 
	return 0;

}



static int

shmem_pread(struct drm_i915_gem_object *obj,

	    const struct drm_i915_gem_pread *arg)

{

	if (!i915_gem_object_has_struct_page(obj))

		return i915_gem_object_pread_phys(obj, arg);



	return -ENODEV;

}



static void shmem_release(struct drm_i915_gem_object *obj)

{

	if (obj->flags & I915_BO_ALLOC_STRUCT_PAGE)

		i915_gem_object_release_memory_region(obj);



	fput(obj->base.filp);
@@ -438,6 +457,7 @@ const struct drm_i915_gem_object_ops i915_gem_shmem_ops = { 
	.writeback = shmem_writeback,



	.pwrite = shmem_pwrite,

	.pread = shmem_pread,



	.release = shmem_release,

};

drivers/gpu/drm/i915/gem/selftests/i915_gem_phys.c

+0 −6
Original line number Diff line number Diff line
@@ -38,12 +38,6 @@ static int mock_phys_object(void *arg) 
	}



	if (i915_gem_object_has_struct_page(obj)) {

		err = -EINVAL;

		pr_err("shmem has a struct page\n");

		goto out_obj;

	}



	if (obj->ops != &i915_gem_phys_ops) {

		pr_err("i915_gem_object_attach_phys did not create a phys object\n");

		err = -EINVAL;

		goto out_obj;