[PATCH v4 2/3] drm/prime: Take a ref on the drm_dev when exporting a dma_buf
Chris Wilson
chris at chris-wilson.co.uk
Wed Oct 5 12:21:44 UTC 2016
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 <daniel.vetter at ffwll.ch>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Petri Latvala <petri.latvala at intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: stable at vger.kernel.org
Tested-by: Petri Latvala <petri.latvala at intel.com>
---
drivers/gpu/drm/armada/armada_gem.c | 2 +-
drivers/gpu/drm/drm_prime.c | 30 +++++++++++++++++++++++++++++-
drivers/gpu/drm/i915/i915_gem_dmabuf.c | 2 +-
drivers/gpu/drm/tegra/gem.c | 2 +-
drivers/gpu/drm/udl/udl_dmabuf.c | 2 +-
include/drm/drmP.h | 4 ++++
6 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index cb8f0347b934..a5e428d27d2f 100644
--- a/drivers/gpu/drm/armada/armada_gem.c
+++ b/drivers/gpu/drm/armada/armada_gem.c
@@ -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 *
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
@@ -284,18 +284,46 @@ static void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
}
/**
+ * 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);
diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index 10265bb35604..97c9d68b45df 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -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;
diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index aa60d9909ea2..95e622e31931 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -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,
diff --git a/drivers/gpu/drm/udl/udl_dmabuf.c b/drivers/gpu/drm/udl/udl_dmabuf.c
index e2243edd1ce3..ac90ffdb5912 100644
--- a/drivers/gpu/drm/udl/udl_dmabuf.c
+++ b/drivers/gpu/drm/udl/udl_dmabuf.c
@@ -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,
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 81fcd553edf7..672644031bd5 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1011,6 +1011,8 @@ static inline int drm_debugfs_remove_files(const struct drm_info_list *files,
}
#endif
+struct dma_buf_export_info;
+
extern struct dma_buf *drm_gem_prime_export(struct drm_device *dev,
struct drm_gem_object *obj,
int flags);
@@ -1021,6 +1023,8 @@ extern struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
struct dma_buf *dma_buf);
extern int drm_gem_prime_fd_to_handle(struct drm_device *dev,
struct drm_file *file_priv, int prime_fd, uint32_t *handle);
+struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
+ struct dma_buf_export_info *exp_info);
extern void drm_gem_dmabuf_release(struct dma_buf *dma_buf);
extern int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages,
--
2.9.3
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