From 99f828436788f0155798145853607ca8f0e6de93 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 28 Jul 2017 22:29:51 +0100
Subject: 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>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: dri-devel@lists.freedesktop.org
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.13-rc1+
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170728212951.7818-1-chris@chris-wilson.co.uk
(cherry picked from commit db1fc97ca0c0d3fdeeadf314d99a26188438940a)
---
 include/linux/sync_file.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'include')

diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h
index 5726107963b2..0ad87c434ae6 100644
--- a/include/linux/sync_file.h
+++ b/include/linux/sync_file.h
@@ -43,12 +43,13 @@ struct sync_file {
 #endif
 
 	wait_queue_head_t	wq;
+	unsigned long		flags;
 
 	struct dma_fence	*fence;
 	struct dma_fence_cb cb;
 };
 
-#define POLL_ENABLED DMA_FENCE_FLAG_USER_BITS
+#define POLL_ENABLED 0
 
 struct sync_file *sync_file_create(struct dma_fence *fence);
 struct dma_fence *sync_file_get_fence(int fd);
-- 
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