[Intel-gfx] [PATCH] drm: fix call_kern.cocci warnings v2

[Chunming Zhou]

drivers/gpu/drm/drm_syncobj.c:202:4-14: ERROR: function drm_syncobj_find_signal_pt_for_point called on line 390 inside lock on line 389 but uses GFP_KERNEL

  Find functions that refer to GFP_KERNEL but are called with locks held.

Semantic patch information:
  The proposed change of converting the GFP_KERNEL is not necessarily the
  correct one.  It may be desired to unlock the lock, or to not call the
  function under the lock in the first place.

Generated by: scripts/coccinelle/locks/call_kern.cocci

v2:
syncobj->timeline still needs protect.

Signed-off-by: Chunming Zhou <david1.zhou at amd.com>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: intel-gfx at lists.freedesktop.org
Cc: Christian König <easy2remember.chk at googlemail.com>
---
 drivers/gpu/drm/drm_syncobj.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index b7eaa603f368..b843d4c2778c 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -111,15 +111,16 @@ static struct dma_fence
 				      uint64_t point)
 {
 	struct drm_syncobj_signal_pt *signal_pt;
+	struct dma_fence *f = NULL;
+	struct drm_syncobj_stub_fence *fence =
+		kzalloc(sizeof(struct drm_syncobj_stub_fence),
+			GFP_KERNEL);
 
+	if (!fence)
+		return NULL;
+	spin_lock(&syncobj->pt_lock);
 	if ((syncobj->type == DRM_SYNCOBJ_TYPE_TIMELINE) &&
 	    (point <= syncobj->timeline)) {
-		struct drm_syncobj_stub_fence *fence =
-			kzalloc(sizeof(struct drm_syncobj_stub_fence),
-				GFP_KERNEL);
-
-		if (!fence)
-			return NULL;
 		spin_lock_init(&fence->lock);
 		dma_fence_init(&fence->base,
 			       &drm_syncobj_stub_fence_ops,
@@ -128,6 +129,7 @@ static struct dma_fence
 			       point);
 
 		dma_fence_signal(&fence->base);
+		spin_unlock(&syncobj->pt_lock);
 		return &fence->base;
 	}
 
@@ -137,9 +139,12 @@ static struct dma_fence
 		if ((syncobj->type == DRM_SYNCOBJ_TYPE_BINARY) &&
 		    (point != signal_pt->value))
 			continue;
-		return dma_fence_get(&signal_pt->fence_array->base);
+		f = dma_fence_get(&signal_pt->fence_array->base);
+		break;
 	}
-	return NULL;
+	spin_unlock(&syncobj->pt_lock);
+	kfree(fence);
+	return f;
 }
 
 static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,
@@ -166,9 +171,7 @@ static void drm_syncobj_fence_get_or_add_callback(struct drm_syncobj *syncobj,
 	}
 
 	mutex_lock(&syncobj->cb_mutex);
-	spin_lock(&syncobj->pt_lock);
 	*fence = drm_syncobj_find_signal_pt_for_point(syncobj, pt_value);
-	spin_unlock(&syncobj->pt_lock);
 	if (!*fence)
 		drm_syncobj_add_callback_locked(syncobj, cb, func);
 	mutex_unlock(&syncobj->cb_mutex);
@@ -379,11 +382,9 @@ drm_syncobj_point_get(struct drm_syncobj *syncobj, u64 point, u64 flags,
 		if (ret < 0)
 			return ret;
 	}
-	spin_lock(&syncobj->pt_lock);
 	*fence = drm_syncobj_find_signal_pt_for_point(syncobj, point);
 	if (!*fence)
 		ret = -EINVAL;
-	spin_unlock(&syncobj->pt_lock);
 	return ret;
 }
 
-- 
2.17.1