[Intel-gfx] [RFC 02/12] dma-fence: Add callback initialization helper

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursu...@intel.com>

In preparation of adding a new field to struct dma_fence_cb we will need
an initialization helper for those callers who add callbacks by open-
coding. That will ensure they initialize all the fields so common code
does not get confused by potential garbage in some fields.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursu...@intel.com>
---
 drivers/dma-buf/dma-fence.c | 10 ++++------
 include/linux/dma-fence.h   |  7 +++++++
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 41da0da17eba..ea4a1f82c9bf 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -662,21 +662,19 @@ int dma_fence_add_callback(struct dma_fence *fence, 
struct dma_fence_cb *cb,
        unsigned long flags;
        int ret = 0;
 
+       __dma_fence_cb_init(cb, func);
+
        if (WARN_ON(!fence || !func))
                return -EINVAL;
 
-       if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags)) {
-               INIT_LIST_HEAD(&cb->node);
+       if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags))
                return -ENOENT;
-       }
 
        spin_lock_irqsave(fence->lock, flags);
 
        if (__dma_fence_enable_signaling(fence)) {
-               cb->func = func;
                list_add_tail(&cb->node, &fence->cb_list);
        } else {
-               INIT_LIST_HEAD(&cb->node);
                ret = -ENOENT;
        }
 
@@ -795,7 +793,7 @@ dma_fence_default_wait(struct dma_fence *fence, bool intr, 
signed long timeout)
                goto out;
        }
 
-       cb.base.func = dma_fence_default_wait_cb;
+       __dma_fence_cb_init(&cb.base, dma_fence_default_wait_cb);
        cb.task = current;
        list_add(&cb.base.node, &fence->cb_list);
 
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 2af328a89468..35933e0ae62c 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -629,4 +629,11 @@ static inline bool dma_fence_is_container(struct dma_fence 
*fence)
        return dma_fence_is_array(fence) || dma_fence_is_chain(fence);
 }
 
+static inline void __dma_fence_cb_init(struct dma_fence_cb *cb,
+                                      dma_fence_func_t func)
+{
+       INIT_LIST_HEAD(&cb->node);
+       cb->func = func;
+}
+
 #endif /* __LINUX_DMA_FENCE_H */
-- 
2.37.2