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authorDave Airlie <airlied@gmail.com>2013-04-22 03:54:36 +0400
committerDave Airlie <airlied@redhat.com>2013-05-01 03:30:15 +0400
commit219b47339ced80ca580bb6ce7d1636166984afa7 (patch)
tree1646e5e3b5998a5b13f71c8f06b7a28a0163fbe7 /drivers/gpu/drm/drm_prime.c
parentc55b6b3da25aa3af36ec51a13a4ed15fef0d7a73 (diff)
downloadlinux-219b47339ced80ca580bb6ce7d1636166984afa7.tar.xz
drm/prime: keep a reference from the handle to exported dma-buf (v6)
Currently we have a problem with this: 1. i915: create gem object 2. i915: export gem object to prime 3. radeon: import gem object 4. close prime fd 5. radeon: unref object 6. 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. v3: cleanup error handling, track import vs export in linked list, these two patches were separate previously, but seem to work better like this. v4: danvet is correct, this code is no longer useful, since the buffer better exist, so remove it. v5: always take a reference to the dma buf object, import or export. (Imre Deak contributed this originally) v6: square the circle, remove import vs export tracking now that there is no difference Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/drm_prime.c')
-rw-r--r--drivers/gpu/drm/drm_prime.c76
1 files changed, 40 insertions, 36 deletions
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 25d02187067e..7830d8e1f212 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -62,6 +62,7 @@ struct drm_prime_member {
struct dma_buf *dma_buf;
uint32_t handle;
};
+static int drm_prime_add_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf, uint32_t handle);
static struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
enum dma_data_direction dir)
@@ -200,7 +201,8 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev,
{
struct drm_gem_object *obj;
void *buf;
- int ret;
+ int ret = 0;
+ struct dma_buf *dmabuf;
obj = drm_gem_object_lookup(dev, file_priv, handle);
if (!obj)
@@ -209,43 +211,44 @@ 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);
- drm_gem_object_unreference_unlocked(obj);
- } 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);
+ 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
+ */
+ ret = PTR_ERR(buf);
+ goto out;
+ }
+ 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);
- if (ret) {
- drm_gem_object_unreference_unlocked(obj);
- mutex_unlock(&file_priv->prime.lock);
- return ret;
- }
+ ret = drm_prime_add_buf_handle(&file_priv->prime,
+ obj->export_dma_buf, handle);
+ if (ret)
+ goto out;
+ *prime_fd = dma_buf_fd(buf, flags);
mutex_unlock(&file_priv->prime.lock);
return 0;
+
+out_have_obj:
+ get_dma_buf(dmabuf);
+ *prime_fd = dma_buf_fd(dmabuf, flags);
+out:
+ drm_gem_object_unreference_unlocked(obj);
+ mutex_unlock(&file_priv->prime.lock);
+ return ret;
}
EXPORT_SYMBOL(drm_gem_prime_handle_to_fd);
@@ -314,7 +317,7 @@ 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;
@@ -333,7 +336,7 @@ int drm_gem_prime_fd_to_handle(struct drm_device *dev,
if (ret)
goto out_put;
- ret = drm_prime_add_imported_buf_handle(&file_priv->prime,
+ ret = drm_prime_add_buf_handle(&file_priv->prime,
dma_buf, *handle);
if (ret)
goto fail;
@@ -487,7 +490,7 @@ 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)
+static 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;
@@ -495,14 +498,14 @@ int drm_prime_add_imported_buf_handle(struct drm_prime_file_private *prime_fpriv
if (!member)
return -ENOMEM;
+ get_dma_buf(dma_buf);
member->dma_buf = dma_buf;
member->handle = handle;
list_add(&member->entry, &prime_fpriv->head);
return 0;
}
-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)
+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;
@@ -514,19 +517,20 @@ 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;
mutex_lock(&prime_fpriv->lock);
list_for_each_entry_safe(member, safe, &prime_fpriv->head, entry) {
if (member->dma_buf == dma_buf) {
+ dma_buf_put(dma_buf);
list_del(&member->entry);
kfree(member);
}
}
mutex_unlock(&prime_fpriv->lock);
}
-EXPORT_SYMBOL(drm_prime_remove_imported_buf_handle);
+EXPORT_SYMBOL(drm_prime_remove_buf_handle);