From a4fce9cb782ad340ee5576a38e934e5e75832dc6 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 5 Oct 2016 13:21:44 +0100 Subject: drm/prime: Take a ref on the drm_dev when exporting a dma_buf MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: Daniel Vetter Signed-off-by: Chris Wilson Cc: Petri Latvala Cc: Daniel Vetter Cc: stable@vger.kernel.org Tested-by: Petri Latvala Reviewed-by: Christian König Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20161005122145.1507-2-chris@chris-wilson.co.uk --- drivers/gpu/drm/drm_prime.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/drm_prime.c') diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 80907b34d857..875df8d719fb 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -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); -- cgit v1.2.3