[PATCH v2] dma-buf/sw_sync: Decrement refcount on error in sw_sync_ioctl_get_deadline()

[Dan Carpenter <dan.carpenter@linaro.org>]

Call dma_fence_put(fence) before returning an error if
dma_fence_to_sync_pt() fails.  Use an unwind ladder at the
end of the function to do the cleanup.

Fixes: 70e67aaec2f4 ("dma-buf/sw_sync: Add fence deadline support")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
v2: style changes.

 drivers/dma-buf/sw_sync.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index f5905d67dedb..22a808995f10 100644
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -438,15 +438,17 @@ static int sw_sync_ioctl_get_deadline(struct sync_timeline *obj, unsigned long a
 		return -EINVAL;
 
 	pt = dma_fence_to_sync_pt(fence);
-	if (!pt)
-		return -EINVAL;
+	if (!pt) {
+		ret = -EINVAL;
+		goto put_fence;
+	}
 
 	spin_lock_irqsave(fence->lock, flags);
-	if (test_bit(SW_SYNC_HAS_DEADLINE_BIT, &fence->flags)) {
-		data.deadline_ns = ktime_to_ns(pt->deadline);
-	} else {
+	if (!test_bit(SW_SYNC_HAS_DEADLINE_BIT, &fence->flags)) {
 		ret = -ENOENT;
+		goto unlock;
 	}
+	data.deadline_ns = ktime_to_ns(pt->deadline);
 	spin_unlock_irqrestore(fence->lock, flags);
 
 	dma_fence_put(fence);
@@ -458,6 +460,13 @@ static int sw_sync_ioctl_get_deadline(struct sync_timeline *obj, unsigned long a
 		return -EFAULT;
 
 	return 0;
+
+unlock:
+	spin_unlock_irqrestore(fence->lock, flags);
+put_fence:
+	dma_fence_put(fence);
+
+	return ret;
 }
 
 static long sw_sync_ioctl(struct file *file, unsigned int cmd,
-- 
2.47.2