[PATCH 1/9] dma-buf: add new dma_fence_chain container v5

[Christian König]

Am 19.03.19 um 13:27 schrieb Lionel Landwerlin:
> On 15/03/2019 12:09, Chunming Zhou wrote:
>> [SNIP]
>> +/**
>> + * struct dma_fence_chain - fence to represent an node of a fence chain
>> + * @base: fence base class
>> + * @lock: spinlock for fence handling
>> + * @prev: previous fence of the chain
>> + * @prev_seqno: original previous seqno before garbage collection
>> + * @fence: encapsulated fence
>> + * @cb: callback structure for signaling
>> + * @work: irq work item for signaling
>> + */
>> +struct dma_fence_chain {
>> +    struct dma_fence base;
>> +    spinlock_t lock;
>> +    struct dma_fence *prev;
>
>
> Not an expert on the rcu thing, but drm_syncobj has a __rcu on its 
> fence field.
>
> Should this be? :
>
>
> struct dma_fence __rcu *prev;

Yeah, the kbuild robot has already complained about this as well.

Needs to be fixed before pushed, but its only a minor change.

Christian.

>
>
>> +    u64 prev_seqno;
>> +    struct dma_fence *fence;
>> +    struct dma_fence_cb cb;
>> +    struct irq_work work;
>> +};
>> +
>> +extern const struct dma_fence_ops dma_fence_chain_ops;
>> +
>> +/**
>> + * to_dma_fence_chain - cast a fence to a dma_fence_chain
>> + * @fence: fence to cast to a dma_fence_array
>> + *
>> + * Returns NULL if the fence is not a dma_fence_chain,
>> + * or the dma_fence_chain otherwise.
>> + */
>> +static inline struct dma_fence_chain *
>> +to_dma_fence_chain(struct dma_fence *fence)
>> +{
>> +    if (!fence || fence->ops != &dma_fence_chain_ops)
>> +        return NULL;
>> +
>> +    return container_of(fence, struct dma_fence_chain, base);
>> +}
>> +
>> +/**
>> + * dma_fence_chain_for_each - iterate over all fences in chain
>> + * @iter: current fence
>> + * @head: starting point
>> + *
>> + * Iterate over all fences in the chain. We keep a reference to the 
>> current
>> + * fence while inside the loop which must be dropped when breaking out.
>> + */
>> +#define dma_fence_chain_for_each(iter, head)    \
>> +    for (iter = dma_fence_get(head); iter; \
>> +         iter = dma_fence_chain_walk(iter))
>> +
>> +struct dma_fence *dma_fence_chain_walk(struct dma_fence *fence);
>> +int dma_fence_chain_find_seqno(struct dma_fence **pfence, uint64_t 
>> seqno);
>> +void dma_fence_chain_init(struct dma_fence_chain *chain,
>> +              struct dma_fence *prev,
>> +              struct dma_fence *fence,
>> +              uint64_t seqno);
>> +
>> +#endif /* __LINUX_DMA_FENCE_CHAIN_H */
>
>