Am 11.03.23 um 18:35 schrieb Rob Clark:
From: Rob Clark robdclark@chromium.org
Add a way to initialize a fence without touching the refcount. This is useful, for example, if the fence is embedded in a drm_sched_job. In this case the refcount will be initialized before the job is queued. But the seqno of the hw_fence is not known until job_run().
Signed-off-by: Rob Clark robdclark@chromium.org
Well that approach won't work. The fence can only be initialized in the job_run() callback because only then the sequence number can be determined.
Regards, Christian.
drivers/dma-buf/dma-fence.c | 43 ++++++++++++++++++++++++++++--------- include/linux/dma-fence.h | 2 ++ 2 files changed, 35 insertions(+), 10 deletions(-)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c index 74e36f6d05b0..97c05a465cb4 100644 --- a/drivers/dma-buf/dma-fence.c +++ b/drivers/dma-buf/dma-fence.c @@ -989,28 +989,27 @@ void dma_fence_describe(struct dma_fence *fence, struct seq_file *seq) EXPORT_SYMBOL(dma_fence_describe); /**
- dma_fence_init - Initialize a custom fence.
- dma_fence_init_noref - Initialize a custom fence without initializing refcount.
- @fence: the fence to initialize
- @ops: the dma_fence_ops for operations on this fence
- @lock: the irqsafe spinlock to use for locking this fence
- @context: the execution context this fence is run on
- @seqno: a linear increasing sequence number for this context
- Initializes an allocated fence, the caller doesn't have to keep its
- refcount after committing with this fence, but it will need to hold a
- refcount again if &dma_fence_ops.enable_signaling gets called.
- context and seqno are used for easy comparison between fences, allowing
- to check which fence is later by simply using dma_fence_later().
- Like &dma_fence_init but does not initialize the refcount. Suitable
- for cases where the fence is embedded in another struct which has it's
- refcount initialized before the fence is initialized. Such as embedding
- in a &drm_sched_job, where the job is created before knowing the seqno
*/ void
- of the hw_fence.
-dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
spinlock_t *lock, u64 context, u64 seqno)+dma_fence_init_noref(struct dma_fence *fence, const struct dma_fence_ops *ops,
spinlock_t *lock, u64 context, u64 seqno)- BUG_ON(!kref_read(&fence->refcount));
- kref_init(&fence->refcount); fence->ops = ops; INIT_LIST_HEAD(&fence->cb_list); fence->lock = lock;
@@ -1021,4 +1020,28 @@ dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops, trace_dma_fence_init(fence); } +EXPORT_SYMBOL(dma_fence_init_noref);
+/**
- dma_fence_init - Initialize a custom fence.
- @fence: the fence to initialize
- @ops: the dma_fence_ops for operations on this fence
- @lock: the irqsafe spinlock to use for locking this fence
- @context: the execution context this fence is run on
- @seqno: a linear increasing sequence number for this context
- Initializes an allocated fence, the caller doesn't have to keep its
- refcount after committing with this fence, but it will need to hold a
- refcount again if &dma_fence_ops.enable_signaling gets called.
- context and seqno are used for easy comparison between fences, allowing
- to check which fence is later by simply using dma_fence_later().
- */
+void +dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
spinlock_t *lock, u64 context, u64 seqno)+{
- kref_init(&fence->refcount);
- dma_fence_init_noref(fence, ops, lock, context, seqno);
+} EXPORT_SYMBOL(dma_fence_init); diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h index d54b595a0fe0..f617c78a2e0a 100644 --- a/include/linux/dma-fence.h +++ b/include/linux/dma-fence.h @@ -279,6 +279,8 @@ struct dma_fence_ops { void (*set_deadline)(struct dma_fence *fence, ktime_t deadline); }; +void dma_fence_init_noref(struct dma_fence *fence, const struct dma_fence_ops *ops,
spinlock_t *lock, u64 context, u64 seqno);