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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_gem.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_gem.c')
-rw-r--r--drivers/gpu/drm/drm_gem.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index af779ae19ebf..cf919e36e8ae 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -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);
}
}