BACKPORT: dma-buf/sync_file: Allow multiple sync_files to wrap a single dma-fence
Up until recently sync_file were create to export a single dma-fence to
userspace, and so we could canabalise a bit insie dma-fence to mark
whether or not we had enable polling for the sync_file itself. However,
with the advent of syncobj, we do allow userspace to create multiple
sync_files for a single dma-fence. (Similarly, that the sw-sync
validation framework also started returning multiple sync-files wrapping
a single dma-fence for a syncpt also triggering the problem.)
This patch reverts my suggestion in commit e24165537312
("dma-buf/sync_file: only enable fence signalling on poll()") to use a
single bit in the shared dma-fence and restores the sync_file->flags for
tracking the bits individually.
Reported-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Fixes: f1e8c67123cf ("dma-buf/sw-sync: Use an rbtree to sort fences in the timeline")
Fixes: e9083420bbac ("drm: introduce sync objects (v4)")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170728212951.7818-1-chris@chris-wilson.co.uk
[astrachan: rediffed against changed context lines in 4.9]
Bug: 79383895
Change-Id: If98fa920693045fdab21886960657bbe8ef550c0
Signed-off-by: Alistair Strachan <astrachan@google.com>
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index c835f62..e16849f 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -279,7 +279,7 @@
struct sync_file *sync_file = container_of(kref, struct sync_file,
kref);
- if (test_bit(POLL_ENABLED, &sync_file->fence->flags))
+ if (test_bit(POLL_ENABLED, &sync_file->flags))
fence_remove_callback(sync_file->fence, &sync_file->cb);
fence_put(sync_file->fence);
kfree(sync_file);
@@ -299,7 +299,8 @@
poll_wait(file, &sync_file->wq, wait);
- if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
+ if (list_empty(&sync_file->cb.node) &&
+ !test_and_set_bit(POLL_ENABLED, &sync_file->flags)) {
if (fence_add_callback(sync_file->fence, &sync_file->cb,
fence_check_cb_func) < 0)
wake_up_all(&sync_file->wq);