[PATCH] drm/vc4: Fix refcounting of runtime PM get if it errors out.

[Eric Anholt <eric@anholt.net>]

We were returning without decrementing if the error happened, meaning
that at the next submit we wouldn't try to bring up the power domain.

Signed-off-by: Eric Anholt <eric@anholt.net>
---

I stumbled across this error when testing my CMA patch with a very low
(64MB) CMA area -- we would oops on the submit after the one that
failed.

 drivers/gpu/drm/vc4/vc4_gem.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 777a8d9afd60..735412e3725a 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -1016,13 +1016,16 @@ vc4_submit_cl_ioctl(struct drm_device *dev, void *data,
 	}
 
 	mutex_lock(&vc4->power_lock);
-	if (vc4->power_refcount++ == 0)
+	if (vc4->power_refcount++ == 0) {
 		ret = pm_runtime_get_sync(&vc4->v3d->pdev->dev);
-	mutex_unlock(&vc4->power_lock);
-	if (ret < 0) {
-		kfree(exec);
-		return ret;
+		if (ret < 0) {
+			mutex_unlock(&vc4->power_lock);
+			vc4->power_refcount--;
+			kfree(exec);
+			return ret;
+		}
 	}
+	mutex_unlock(&vc4->power_lock);
 
 	exec->args = args;
 	INIT_LIST_HEAD(&exec->unref_list);
-- 
2.11.0