From ea4d5a270b57fa8d4871f372ca9b97b7697fdfda Mon Sep 17 00:00:00 2001
From: Dominik Behr <dbehr@chromium.org>
Date: Thu, 7 Sep 2017 16:02:46 -0300
Subject: [PATCH] dma-buf/sw_sync: force signal all unsignaled fences on dying timeline
Git-commit: ea4d5a270b57fa8d4871f372ca9b97b7697fdfda
Patch-mainline: v4.15-rc1
References: bsc#794563

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.

V2: Do not bother with cleanup do the list (Chris Wilson)

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dominik Behr <dbehr@chromium.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170907190246.16425-2-gustavo@padovan.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/dma-buf/sw_sync.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index 38cc7389a6c1..24f83f9eeaed 100644
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -321,8 +321,16 @@ 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;
+
+	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);
+	}
 
-	smp_wmb();
+	spin_unlock_irq(&obj->lock);
 
 	sync_timeline_put(obj);
 	return 0;
-- 
2.20.1