Am 21.01.22 um 08:41 schrieb Thomas Hellström (Intel):
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@amd.com
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?
Good question.
I think that all containers which also implement the dma_fence interface should be part of the DMA-buf subsystem and not driver specific. Drivers just tend to reinvent something incorrectly.
Where/How should we document that?
Regards, Christian.
Thanks, /Thomas
#endif /* __LINUX_DMA_FENCE_H */