Commit a4fce9cb authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

drm/prime: Take a ref on the drm_dev when exporting a dma_buf 



dma_buf may live a long time, longer than the last direct user of the
driver. We already hold a reference to the owner module (that prevents
the object code from disappearing), but there is no reference to the
drm_dev - so the pointers to the driver backend themselves may vanish.

v2: Resist temptation to fix the bug in armada_gem.c not setting the
correct flags on the exported dma-buf (it should pass the flags through
and not be arbitrarily setting O_RDWR).

Use a common wrapper for exporting the dmabuf and acquiring the
reference to the drm_device.

Testcase: igt/vgem_basic/unload
Suggested-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Petri Latvala <petri.latvala@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Tested-by: default avatarPetri Latvala <petri.latvala@intel.com>
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161005122145.1507-2-chris@chris-wilson.co.uk
parent 56a76c01

drivers/gpu/drm/armada/armada_gem.c

+1 −1
Original line number Diff line number Diff line
@@ -547,7 +547,7 @@ armada_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj, 
	exp_info.flags = O_RDWR;

	exp_info.priv = obj;



	return dma_buf_export(&exp_info);

	return drm_gem_dmabuf_export(dev, &exp_info);

}



struct drm_gem_object *

drivers/gpu/drm/drm_prime.c

+29 −1
Original line number Diff line number Diff line
@@ -283,19 +283,47 @@ static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach, 
	/* nothing to be done here */

}



/**

 * drm_gem_dmabuf_export - dma_buf export implementation for GEM

 * @dma_buf: buffer to be exported

 *

 * This wraps dma_buf_export() for use by generic GEM drivers that are using

 * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take

 * a reference to the drm_device which is released by drm_gem_dmabuf_release().

 *

 * Returns the new dmabuf.

 */

struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,

				      struct dma_buf_export_info *exp_info)

{

	struct dma_buf *dma_buf;



	dma_buf = dma_buf_export(exp_info);

	if (!IS_ERR(dma_buf))

		drm_dev_ref(dev);



	return dma_buf;

}

EXPORT_SYMBOL(drm_gem_dmabuf_export);



/**

 * drm_gem_dmabuf_release - dma_buf release implementation for GEM

 * @dma_buf: buffer to be released

 *

 * Generic release function for dma_bufs exported as PRIME buffers. GEM drivers

 * must use this in their dma_buf ops structure as the release callback.

 * drm_gem_dmabuf_release() should be used in conjunction with

 * drm_gem_dmabuf_export().

 */

void drm_gem_dmabuf_release(struct dma_buf *dma_buf)

{

	struct drm_gem_object *obj = dma_buf->priv;

	struct drm_device *dev = obj->dev;



	/* drop the reference on the export fd holds */

	drm_gem_object_unreference_unlocked(obj);



	drm_dev_unref(dev);

}

EXPORT_SYMBOL(drm_gem_dmabuf_release);
@@ -412,7 +440,7 @@ struct dma_buf *drm_gem_prime_export(struct drm_device *dev, 
	if (dev->driver->gem_prime_res_obj)

		exp_info.resv = dev->driver->gem_prime_res_obj(obj);



	return dma_buf_export(&exp_info);

	return drm_gem_dmabuf_export(dev, &exp_info);

}

EXPORT_SYMBOL(drm_gem_prime_export);

drivers/gpu/drm/i915/i915_gem_dmabuf.c

+1 −1
Original line number Diff line number Diff line
@@ -283,7 +283,7 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev, 
			return ERR_PTR(ret);

	}



	dma_buf = dma_buf_export(&exp_info);

	dma_buf = drm_gem_dmabuf_export(dev, &exp_info);

	if (IS_ERR(dma_buf))

		return dma_buf;

drivers/gpu/drm/tegra/gem.c

+1 −1
Original line number Diff line number Diff line
@@ -613,7 +613,7 @@ struct dma_buf *tegra_gem_prime_export(struct drm_device *drm, 
	exp_info.flags = flags;

	exp_info.priv = gem;



	return dma_buf_export(&exp_info);

	return drm_gem_dmabuf_export(drm, &exp_info);

}



struct drm_gem_object *tegra_gem_prime_import(struct drm_device *drm,

drivers/gpu/drm/udl/udl_dmabuf.c

+1 −1
Original line number Diff line number Diff line
@@ -209,7 +209,7 @@ struct dma_buf *udl_gem_prime_export(struct drm_device *dev, 
	exp_info.flags = flags;

	exp_info.priv = obj;



	return dma_buf_export(&exp_info);

	return drm_gem_dmabuf_export(dev, &exp_info);

}



static int udl_prime_create(struct drm_device *dev,

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