OpenE2K
/
linux
6
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

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>
This commit is contained in:
Dave Airlie 2013-04-22 09:54:36 +10:00 committed by Dave Airlie
parent c55b6b3da2
commit 219b47339c
3 changed files with 44 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/gpu/drm/drm_gem.c
View File

@ -205,11 +205,11 @@ static void
drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
{
if (obj->import_attach) {
drm_prime_remove_imported_buf_handle(&filp->prime,
drm_prime_remove_buf_handle(&filp->prime,
obj->import_attach->dmabuf);
}
if (obj->export_dma_buf) {
drm_prime_remove_imported_buf_handle(&filp->prime,
drm_prime_remove_buf_handle(&filp->prime,
obj->export_dma_buf);
}
}

76
drivers/gpu/drm/drm_prime.c
View File

@ -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);

5
include/drm/drmP.h
View File

@ -1593,9 +1593,8 @@ 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);
void drm_prime_remove_imported_buf_handle(struct drm_prime_file_private *prime_fpriv, struct dma_buf *dma_buf);
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_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,