[PATCH v2 2/2] drm/prime: Take a ref on the drm_dev when exporting a dma_buf
From: Chris Wilson <hidden>
Date: 2016-09-30 11:44:56
Also in:
dri-devel, intel-gfx
Subsystem:
drm driver for usb displaylink video adapters, drm drivers, drm drivers and misc gpu patches, drm drivers for nvidia tegra, intel drm i915 driver (meteor lake, dg2 and older excluding poulsbo, moorestown and derivative), marvell armada drm support, the rest · Maintainers:
Dave Airlie, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Thierry Reding, Mikko Perttunen, Jani Nikula, Joonas Lahtinen, Rodrigo Vivi, Tvrtko Ursulin, Russell King, Linus Torvalds
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. Suggested-by: Daniel Vetter <redacted> Signed-off-by: Chris Wilson <redacted> Cc: Petri Latvala <redacted> Cc: Daniel Vetter <redacted> Cc: stable@vger.kernel.org --- drivers/gpu/drm/armada/armada_gem.c | 9 +++++++-- drivers/gpu/drm/drm_prime.c | 10 +++++++++- drivers/gpu/drm/i915/i915_gem_dmabuf.c | 1 + drivers/gpu/drm/tegra/gem.c | 7 ++++++- drivers/gpu/drm/udl/udl_dmabuf.c | 7 ++++++- 5 files changed, 29 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index cb8f0347b934..bdd3af043827 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c@@ -541,13 +541,18 @@ armada_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj, int flags) { DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct dma_buf *dma_buf; exp_info.ops = &armada_gem_prime_dmabuf_ops; exp_info.size = obj->size; - exp_info.flags = O_RDWR; + exp_info.flags = flags; exp_info.priv = obj; - return dma_buf_export(&exp_info); + dma_buf = dma_buf_export(&exp_info); + if (!IS_ERR(dma_buf)) + drm_dev_ref(dev); + + return dma_buf; } struct drm_gem_object *
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 443b6da011ff..add375f54b6d 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c@@ -293,9 +293,12 @@ static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach, 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);
@@ -413,11 +416,16 @@ struct dma_buf *drm_gem_prime_export(struct drm_device *dev, .flags = flags, .priv = obj, }; + struct dma_buf *dma_buf; if (dev->driver->gem_prime_res_obj) exp_info.resv = dev->driver->gem_prime_res_obj(obj); - return dma_buf_export(&exp_info); + dma_buf = dma_buf_export(&exp_info); + if (!IS_ERR(dma_buf)) + drm_dev_ref(dev); + + return dma_buf; } EXPORT_SYMBOL(drm_gem_prime_export);
diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index 10265bb35604..b58b2e63add1 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c@@ -288,6 +288,7 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev, return dma_buf; export_fences(obj, dma_buf); + drm_dev_ref(obj->base.dev); return dma_buf; }
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index aa60d9909ea2..aaae8b6ba668 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c@@ -607,13 +607,18 @@ struct dma_buf *tegra_gem_prime_export(struct drm_device *drm, int flags) { DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct dma_buf *dma_buf; exp_info.ops = &tegra_gem_prime_dmabuf_ops; exp_info.size = gem->size; exp_info.flags = flags; exp_info.priv = gem; - return dma_buf_export(&exp_info); + dma_buf = dma_buf_export(&exp_info); + if (!IS_ERR(dma_buf)) + drm_dev_ref(drm); + + return dma_buf; } struct drm_gem_object *tegra_gem_prime_import(struct drm_device *drm,
diff --git a/drivers/gpu/drm/udl/udl_dmabuf.c b/drivers/gpu/drm/udl/udl_dmabuf.c
index e2243edd1ce3..249cc1072112 100644
--- a/drivers/gpu/drm/udl/udl_dmabuf.c
+++ b/drivers/gpu/drm/udl/udl_dmabuf.c@@ -203,13 +203,18 @@ struct dma_buf *udl_gem_prime_export(struct drm_device *dev, struct drm_gem_object *obj, int flags) { DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct dma_buf *dma_buf; exp_info.ops = &udl_dmabuf_ops; exp_info.size = obj->size; exp_info.flags = flags; exp_info.priv = obj; - return dma_buf_export(&exp_info); + dma_buf = dma_buf_export(&exp_info); + if (!IS_ERR(dma_buf)) + drm_dev_ref(dev); + + return dma_buf; } static int udl_prime_create(struct drm_device *dev,
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2.9.3