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Commit 5cfacded authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
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drm/i915: Pin pages whilst mapping the dma-buf 



As we attempt to kmalloc after calling get_pages, there is a possibility
that the shrinker may reap the pages we just acquired. To prevent this
we need to increment the pages_pin_count early, so rearrange the code
and error paths to make it so.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 1f5d76db

drivers/gpu/drm/i915/i915_gem_dmabuf.c

+22 −19
Original line number Diff line number Diff line
@@ -42,27 +42,24 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme 


	ret = i915_mutex_lock_interruptible(obj->base.dev);

	if (ret)

		return ERR_PTR(ret);

		goto err;



	ret = i915_gem_object_get_pages(obj);

	if (ret) {

		st = ERR_PTR(ret);

		goto out;

	}

	if (ret)

		goto err_unlock;



	i915_gem_object_pin_pages(obj);



	/* Copy sg so that we make an independent mapping */

	st = kmalloc(sizeof(struct sg_table), GFP_KERNEL);

	if (st == NULL) {

		st = ERR_PTR(-ENOMEM);

		goto out;

		ret = -ENOMEM;

		goto err_unpin;

	}



	ret = sg_alloc_table(st, obj->pages->nents, GFP_KERNEL);

	if (ret) {

		kfree(st);

		st = ERR_PTR(ret);

		goto out;

	}

	if (ret)

		goto err_free;



	src = obj->pages->sgl;

	dst = st->sgl;
@@ -73,17 +70,23 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme 
	}



	if (!dma_map_sg(attachment->dev, st->sgl, st->nents, dir)) {

		sg_free_table(st);

		kfree(st);

		st = ERR_PTR(-ENOMEM);

		goto out;

		ret =-ENOMEM;

		goto err_free_sg;

	}



	i915_gem_object_pin_pages(obj);



out:

	mutex_unlock(&obj->base.dev->struct_mutex);

	return st;



err_free_sg:

	sg_free_table(st);

err_free:

	kfree(st);

err_unpin:

	i915_gem_object_unpin_pages(obj);

err_unlock:

	mutex_unlock(&obj->base.dev->struct_mutex);

err:

	return ERR_PTR(ret);

}



static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,