From 48cb8debada5b23233439c92cfd304c9dd96dcde Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Mon, 10 Feb 2020 14:41:39 +0100
Subject: drm/ttm: use RCU in ttm_bo_flush_all_fences
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Git-commit: e81a2557e0650ee0ce37ba14476ddb709d6daf57
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

This allows it to call the function without the lock held.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: xinhui pan <xinhui.pan@amd.com>
Link: https://patchwork.freedesktop.org/patch/352742/
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/ttm/ttm_bo.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index c1104c8857b7..e12fc2c2d165 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -429,22 +429,24 @@ static int ttm_bo_individualize_resv(struct ttm_buffer_object *bo)
 
 static void ttm_bo_flush_all_fences(struct ttm_buffer_object *bo)
 {
+	struct dma_resv *resv = &bo->base._resv;
 	struct dma_resv_list *fobj;
 	struct dma_fence *fence;
 	int i;
 
-	fobj = dma_resv_get_list(&bo->base._resv);
-	fence = dma_resv_get_excl(&bo->base._resv);
+	rcu_read_lock();
+	fobj = rcu_dereference(resv->fence);
+	fence = rcu_dereference(resv->fence_excl);
 	if (fence && !fence->ops->signaled)
 		dma_fence_enable_sw_signaling(fence);
 
 	for (i = 0; fobj && i < fobj->shared_count; ++i) {
-		fence = rcu_dereference_protected(fobj->shared[i],
-					dma_resv_held(bo->base.resv));
+		fence = rcu_dereference(fobj->shared[i]);
 
 		if (!fence->ops->signaled)
 			dma_fence_enable_sw_signaling(fence);
 	}
+	rcu_read_unlock();
 }
 
 static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo)
-- 
2.28.0