On Wed, 2013-04-10 at 10:56 +1000, Dave Airlie wrote:
Currently we have a problem with this:
- i915: create gem object
- i915: export gem object to prime
- radeon: import gem object
- close prime fd
- radeon: unref object
- i915: unref object
i915 has an imported object reference in its file priv, that isn't cleaned up properly until fd close. The reference gets added at step 2, but at step 6 we don't have enough info to clean it up.
The solution is to take a reference on the dma-buf when we export it, and drop the reference when the gem handle goes away.
So when we export a dma_buf from a gem object, we keep track of it with the handle, we take a reference to the dma_buf. When we close the handle (i.e. userspace is finished with the buffer), we drop the reference to the dma_buf, and it gets collected.
This patch isn't meant to fix any other problem or bikesheds, and it doesn't fix any races with other scenarios.
v1.1: move export symbol line back up.
v2: okay I had to do a bit more, as the first patch showed a leak on one of my tests, that I found using the dma-buf debugfs support, the problem case is exporting a buffer twice with the same handle, we'd add another export handle for it unnecessarily, however we now fail if we try to export the same object with a different gem handle, however I'm not sure if that is a case I want to support, and I've gotten the code to WARN_ON if we hit something like that.
v2.1: rebase this patch, write better commit msg.
Signed-off-by: Dave Airlie airlied@redhat.com
This fixes the i-g-t/prime_self_import test case too, so fwiw: Acked-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/drm_gem.c | 2 +- drivers/gpu/drm/drm_prime.c | 94 ++++++++++++++++++++++++++++++++------------- include/drm/drmP.h | 3 +- 3 files changed, 71 insertions(+), 28 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index af779ae..f0f7a86 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -209,7 +209,7 @@ drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp) obj->import_attach->dmabuf); } if (obj->export_dma_buf) {
drm_prime_remove_imported_buf_handle(&filp->prime,
drm_prime_remove_exported_buf_handle(&filp->prime, obj->export_dma_buf);} diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 366910d..05ee250 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -157,6 +157,8 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { .vunmap = drm_gem_dmabuf_vunmap, };
+static int drm_prime_add_exported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle);
/**
- DOC: PRIME Helpers
@@ -201,6 +203,8 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev, struct drm_gem_object *obj; void *buf; int ret;
struct dma_buf *dmabuf;
uint32_t exp_handle;
obj = drm_gem_object_lookup(dev, file_priv, handle); if (!obj)
@@ -209,41 +213,52 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev, mutex_lock(&file_priv->prime.lock); /* re-export the original imported object */ if (obj->import_attach) {
get_dma_buf(obj->import_attach->dmabuf);*prime_fd = dma_buf_fd(obj->import_attach->dmabuf, flags);drm_gem_object_unreference_unlocked(obj);mutex_unlock(&file_priv->prime.lock);return 0;
dmabuf = obj->import_attach->dmabuf;goto out_have_obj;}
if (obj->export_dma_buf) {
get_dma_buf(obj->export_dma_buf);*prime_fd = dma_buf_fd(obj->export_dma_buf, flags);
dmabuf = obj->export_dma_buf;goto out_have_obj;- }
- buf = dev->driver->gem_prime_export(dev, obj, flags);
- if (IS_ERR(buf)) {
/* normally the created dma-buf takes ownership of the ref,* but if that fails then drop the ref*/
- } else {
buf = dev->driver->gem_prime_export(dev, obj, flags);if (IS_ERR(buf)) {/* normally the created dma-buf takes ownership of the ref,* but if that fails then drop the ref*/drm_gem_object_unreference_unlocked(obj);mutex_unlock(&file_priv->prime.lock);return PTR_ERR(buf);}obj->export_dma_buf = buf;*prime_fd = dma_buf_fd(buf, flags);
mutex_unlock(&file_priv->prime.lock);return PTR_ERR(buf);- obj->export_dma_buf = buf;
- /* if we've exported this buffer the cheat and add it to the import list
*/
- so we get the correct handle back
- ret = drm_prime_add_imported_buf_handle(&file_priv->prime,
obj->export_dma_buf, handle);
- ret = drm_prime_add_exported_buf_handle(&file_priv->prime,
obj->export_dma_buf, handle);- *prime_fd = dma_buf_fd(buf, flags);
- mutex_unlock(&file_priv->prime.lock);
- return 0;
+out_have_obj:
- get_dma_buf(dmabuf);
- ret = drm_prime_lookup_buf_handle(&file_priv->prime,
dmabuf, &exp_handle);- if (WARN_ON(ret == -ENOENT || exp_handle != handle)) {
dma_buf_put(dmabuf);drm_gem_object_unreference_unlocked(obj);mutex_unlock(&file_priv->prime.lock);return -EINVAL;- }
- *prime_fd = dma_buf_fd(dmabuf, flags);
- drm_gem_object_unreference_unlocked(obj); mutex_unlock(&file_priv->prime.lock); return 0;
} @@ -314,7 +329,7 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
mutex_lock(&file_priv->prime.lock);
- ret = drm_prime_lookup_imported_buf_handle(&file_priv->prime,
- ret = drm_prime_lookup_buf_handle(&file_priv->prime, dma_buf, handle); if (!ret) { ret = 0;
@@ -491,7 +506,7 @@ void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv) } EXPORT_SYMBOL(drm_prime_destroy_file_private);
-int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) +int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) { struct drm_prime_member *member;
@@ -504,9 +519,21 @@ int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv list_add(&member->entry, &prime_fpriv->head); return 0; }
+int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) +{
- return drm_prime_add_buf_handle(prime_fpriv, dma_buf, handle);
+} EXPORT_SYMBOL(drm_prime_add_imported_buf_handle);
-int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle) +static int drm_prime_add_exported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle) +{
- /* take a reference to the buf handle for this case */
- get_dma_buf(dma_buf);
- return drm_prime_add_buf_handle(prime_fpriv, dma_buf, handle);
+}
+int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle) { struct drm_prime_member *member;
@@ -518,9 +545,9 @@ int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fp } return -ENOENT; } -EXPORT_SYMBOL(drm_prime_lookup_imported_buf_handle); +EXPORT_SYMBOL(drm_prime_lookup_buf_handle);
-void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) +void drm_prime_remove_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) { struct drm_prime_member *member, *safe;
@@ -533,4 +560,19 @@ void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_f } mutex_unlock(&prime_fpriv->lock); }
+void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) +{
- return drm_prime_remove_buf_handle(prime_fpriv, dma_buf);
+} EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle);
+void drm_prime_remove_exported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf) +{
- drm_prime_remove_buf_handle(prime_fpriv, dma_buf);
- dma_buf_put(dma_buf);
+} +EXPORT_SYMBOL(drm_prime_remove_exported_buf_handle);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 2d94d74..0466808 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1594,8 +1594,9 @@ extern void drm_prime_gem_destroy(struct drm_gem_object *obj, struct sg_table *s void drm_prime_init_file_private(struct drm_prime_file_private *prime_fpriv); void drm_prime_destroy_file_private(struct drm_prime_file_private *prime_fpriv); int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle); -int drm_prime_lookup_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle); +int drm_prime_lookup_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t *handle); void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf); +void drm_prime_remove_exported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf);
int drm_prime_add_dma_buf(struct drm_device *dev, struct drm_gem_object *obj); int drm_prime_lookup_obj(struct drm_device *dev, struct dma_buf *buf,