1 files changed, 55 insertions, 78 deletions

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 59ac96ec7ba8..052a41e2451c 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -60,7 +60,7 @@ static atomic64_t dma_fence_context_counter = ATOMIC64_INIT(1);
  *
  * - Then there's also implicit fencing, where the synchronization points are
  *   implicitly passed around as part of shared &dma_buf instances. Such
- *   implicit fences are stored in &struct reservation_object through the
+ *   implicit fences are stored in &struct dma_resv through the
  *   &dma_buf.resv pointer.
  */
 
@@ -129,31 +129,27 @@ EXPORT_SYMBOL(dma_fence_context_alloc);
 int dma_fence_signal_locked(struct dma_fence *fence)
 {
 	struct dma_fence_cb *cur, *tmp;
-	int ret = 0;
+	struct list_head cb_list;
 
 	lockdep_assert_held(fence->lock);
 
-	if (WARN_ON(!fence))
+	if (unlikely(test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
+				      &fence->flags)))
 		return -EINVAL;
 
-	if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
-		ret = -EINVAL;
+	/* Stash the cb_list before replacing it with the timestamp */
+	list_replace(&fence->cb_list, &cb_list);
 
-		/*
-		 * we might have raced with the unlocked dma_fence_signal,
-		 * still run through all callbacks
-		 */
-	} else {
-		fence->timestamp = ktime_get();
-		set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
-		trace_dma_fence_signaled(fence);
-	}
+	fence->timestamp = ktime_get();
+	set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
+	trace_dma_fence_signaled(fence);
 
-	list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
-		list_del_init(&cur->node);
+	list_for_each_entry_safe(cur, tmp, &cb_list, node) {
+		INIT_LIST_HEAD(&cur->node);
 		cur->func(fence, cur);
 	}
-	return ret;
+
+	return 0;
 }
 EXPORT_SYMBOL(dma_fence_signal_locked);
 
@@ -173,28 +169,16 @@ EXPORT_SYMBOL(dma_fence_signal_locked);
 int dma_fence_signal(struct dma_fence *fence)
 {
 	unsigned long flags;
+	int ret;
 
 	if (!fence)
 		return -EINVAL;
 
-	if (test_and_set_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
-		return -EINVAL;
-
-	fence->timestamp = ktime_get();
-	set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
-	trace_dma_fence_signaled(fence);
-
-	if (test_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags)) {
-		struct dma_fence_cb *cur, *tmp;
+	spin_lock_irqsave(fence->lock, flags);
+	ret = dma_fence_signal_locked(fence);
+	spin_unlock_irqrestore(fence->lock, flags);
 
-		spin_lock_irqsave(fence->lock, flags);
-		list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
-			list_del_init(&cur->node);
-			cur->func(fence, cur);
-		}
-		spin_unlock_irqrestore(fence->lock, flags);
-	}
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL(dma_fence_signal);
 
@@ -248,7 +232,8 @@ void dma_fence_release(struct kref *kref)
 
 	trace_dma_fence_destroy(fence);
 
-	if (WARN(!list_empty(&fence->cb_list),
+	if (WARN(!list_empty(&fence->cb_list) &&
+		 !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags),
 		 "Fence %s:%s:%llx:%llx released with pending signals!\n",
 		 fence->ops->get_driver_name(fence),
 		 fence->ops->get_timeline_name(fence),
@@ -288,6 +273,30 @@ void dma_fence_free(struct dma_fence *fence)
 }
 EXPORT_SYMBOL(dma_fence_free);
 
+static bool __dma_fence_enable_signaling(struct dma_fence *fence)
+{
+	bool was_set;
+
+	lockdep_assert_held(fence->lock);
+
+	was_set = test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
+				   &fence->flags);
+
+	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+		return false;
+
+	if (!was_set && fence->ops->enable_signaling) {
+		trace_dma_fence_enable_signal(fence);
+
+		if (!fence->ops->enable_signaling(fence)) {
+			dma_fence_signal_locked(fence);
+			return false;
+		}
+	}
+
+	return true;
+}
+
 /**
  * dma_fence_enable_sw_signaling - enable signaling on fence
  * @fence: the fence to enable
@@ -300,19 +309,12 @@ void dma_fence_enable_sw_signaling(struct dma_fence *fence)
 {
 	unsigned long flags;
 
-	if (!test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
-			      &fence->flags) &&
-	    !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) &&
-	    fence->ops->enable_signaling) {
-		trace_dma_fence_enable_signal(fence);
-
-		spin_lock_irqsave(fence->lock, flags);
-
-		if (!fence->ops->enable_signaling(fence))
-			dma_fence_signal_locked(fence);
+	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+		return;
 
-		spin_unlock_irqrestore(fence->lock, flags);
-	}
+	spin_lock_irqsave(fence->lock, flags);
+	__dma_fence_enable_signaling(fence);
+	spin_unlock_irqrestore(fence->lock, flags);
 }
 EXPORT_SYMBOL(dma_fence_enable_sw_signaling);
 
@@ -346,7 +348,6 @@ int dma_fence_add_callback(struct dma_fence *fence, struct dma_fence_cb *cb,
 {
 	unsigned long flags;
 	int ret = 0;
-	bool was_set;
 
 	if (WARN_ON(!fence || !func))
 		return -EINVAL;
@@ -358,25 +359,14 @@ int dma_fence_add_callback(struct dma_fence *fence, struct dma_fence_cb *cb,
 
 	spin_lock_irqsave(fence->lock, flags);
 
-	was_set = test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
-				   &fence->flags);
-
-	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
-		ret = -ENOENT;
-	else if (!was_set && fence->ops->enable_signaling) {
-		trace_dma_fence_enable_signal(fence);
-
-		if (!fence->ops->enable_signaling(fence)) {
-			dma_fence_signal_locked(fence);
-			ret = -ENOENT;
-		}
-	}
-
-	if (!ret) {
+	if (__dma_fence_enable_signaling(fence)) {
 		cb->func = func;
 		list_add_tail(&cb->node, &fence->cb_list);
-	} else
+	} else {
 		INIT_LIST_HEAD(&cb->node);
+		ret = -ENOENT;
+	}
+
 	spin_unlock_irqrestore(fence->lock, flags);
 
 	return ret;
@@ -476,7 +466,6 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout)
 	struct default_wait_cb cb;
 	unsigned long flags;
 	signed long ret = timeout ? timeout : 1;
-	bool was_set;
 
 	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
 		return ret;
@@ -488,21 +477,9 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, signed long timeout)
 		goto out;
 	}
 
-	was_set = test_and_set_bit(DMA_FENCE_FLAG_ENABLE_SIGNAL_BIT,
-				   &fence->flags);
-
-	if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+	if (!__dma_fence_enable_signaling(fence))
 		goto out;
 
-	if (!was_set && fence->ops->enable_signaling) {
-		trace_dma_fence_enable_signal(fence);
-
-		if (!fence->ops->enable_signaling(fence)) {
-			dma_fence_signal_locked(fence);
-			goto out;
-		}
-	}
-
 	if (!timeout) {
 		ret = 0;
 		goto out;