Quoting Gustavo Padovan (2017-09-05 00:06:04)
From: Dominik Behr dbehr@chromium.org
To avoid hanging userspace components that might have been waiting on the active fences of the destroyed timeline we need to signal with error all remaining fences on such timeline.
This restore the default behaviour of the Android sw_sync framework, which Android still relies on. It was broken on the dma fence conversion a few years ago and never fixed.
Signed-off-by: Dominik Behr dbehr@chromium.org Signed-off-by: Gustavo Padovan gustavo.padovan@collabora.com
drivers/dma-buf/sw_sync.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c index 38cc7389a6c1..a85198c75a1b 100644 --- a/drivers/dma-buf/sw_sync.c +++ b/drivers/dma-buf/sw_sync.c @@ -321,9 +321,21 @@ static int sw_sync_debugfs_open(struct inode *inode, struct file *file) static int sw_sync_debugfs_release(struct inode *inode, struct file *file) { struct sync_timeline *obj = file->private_data;
struct sync_pt *pt, *next; smp_wmb();spin_lock_irq(&obj->lock);list_for_each_entry_safe(pt, next, &obj->pt_list, link) {dma_fence_set_error(&pt->base, -ENOENT);dma_fence_signal_locked(&pt->base);list_del_init(&pt->link);rb_erase(&pt->node, &obj->pt_tree);
Since the timeline is dead, we don't need to worry about trimming the completed signals from the timeline. No need for the list_del/rb_erase here, especially considering the trickiness required to avoid the potential deadlock which is missing here. -Chris