On 1/20/22 14:27, Christian König wrote:
Consolidate the wrapper functions to check for dma_fence
subclasses in the dma_fence header.
This makes it easier to document and also check the different
requirements for fence containers in the subclasses.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
include/linux/dma-fence-array.h | 15 +------------
include/linux/dma-fence-chain.h | 3 +--
include/linux/dma-fence.h | 38 +++++++++++++++++++++++++++++++++
3 files changed, 40 insertions(+), 16 deletions(-)
diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h
index 303dd712220f..fec374f69e12 100644
--- a/include/linux/dma-fence-array.h
+++ b/include/linux/dma-fence-array.h
@@ -45,19 +45,6 @@ struct dma_fence_array {
struct irq_work work;
};
-extern const struct dma_fence_ops dma_fence_array_ops;
-
-/**
- * dma_fence_is_array - check if a fence is from the array subsclass
- * @fence: fence to test
- *
- * Return true if it is a dma_fence_array and false otherwise.
- */
-static inline bool dma_fence_is_array(struct dma_fence *fence)
-{
- return fence->ops == &dma_fence_array_ops;
-}
-
/**
* to_dma_fence_array - cast a fence to a dma_fence_array
* @fence: fence to cast to a dma_fence_array
@@ -68,7 +55,7 @@ static inline bool dma_fence_is_array(struct dma_fence *fence)
static inline struct dma_fence_array *
to_dma_fence_array(struct dma_fence *fence)
{
- if (fence->ops != &dma_fence_array_ops)
+ if (!fence || !dma_fence_is_array(fence))
return NULL;
return container_of(fence, struct dma_fence_array, base);
diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h
index 54fe3443fd2c..ee906b659694 100644
--- a/include/linux/dma-fence-chain.h
+++ b/include/linux/dma-fence-chain.h
@@ -49,7 +49,6 @@ struct dma_fence_chain {
spinlock_t lock;
};
-extern const struct dma_fence_ops dma_fence_chain_ops;
/**
* to_dma_fence_chain - cast a fence to a dma_fence_chain
@@ -61,7 +60,7 @@ extern const struct dma_fence_ops dma_fence_chain_ops;
static inline struct dma_fence_chain *
to_dma_fence_chain(struct dma_fence *fence)
{
- if (!fence || fence->ops != &dma_fence_chain_ops)
+ if (!fence || !dma_fence_is_chain(fence))
return NULL;
return container_of(fence, struct dma_fence_chain, base);
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 1ea691753bd3..775cdc0b4f24 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -587,4 +587,42 @@ struct dma_fence *dma_fence_get_stub(void);
struct dma_fence *dma_fence_allocate_private_stub(void);
u64 dma_fence_context_alloc(unsigned num);
+extern const struct dma_fence_ops dma_fence_array_ops;
+extern const struct dma_fence_ops dma_fence_chain_ops;
+
+/**
+ * dma_fence_is_array - check if a fence is from the array subclass
+ * @fence: the fence to test
+ *
+ * Return true if it is a dma_fence_array and false otherwise.
+ */
+static inline bool dma_fence_is_array(struct dma_fence *fence)
+{
+ return fence->ops == &dma_fence_array_ops;
+}
+
+/**
+ * dma_fence_is_chain - check if a fence is from the chain subclass
+ * @fence: the fence to test
+ *
+ * Return true if it is a dma_fence_chain and false otherwise.
+ */
+static inline bool dma_fence_is_chain(struct dma_fence *fence)
+{
+ return fence->ops == &dma_fence_chain_ops;
+}
+
+/**
+ * dma_fence_is_container - check if a fence is a container for other fences
+ * @fence: the fence to test
+ *
+ * Return true if this fence is a container for other fences, false otherwise.
+ * This is important since we can't build up large fence structure or otherwise
+ * we run into recursion during operation on those fences.
+ */
+static inline bool dma_fence_is_container(struct dma_fence *fence)
+{
+ return dma_fence_is_array(fence) || dma_fence_is_chain(fence);
+}
What's the strategy here moving forward if we add more dma_resv
containers, or if a driver adds a container that similarly has risc of
recursion? Should we perhaps add an ops bool for this, or require that
all dma_resv containers that has this limitation be part of the dma-buf
subsystem rather than driver-specific?
Thanks,
/Thomas
+
#endif /* __LINUX_DMA_FENCE_H */
