[PATCH v2 1/2] dma-buf: Split out dma fence array create into alloc and arm functions

[Matthew Brost]

On Mon, Aug 26, 2024 at 07:57:07PM +0200, Christian König wrote:
> Am 26.08.24 um 19:01 schrieb Matthew Brost:
> > Useful to preallocate dma fence array and then arm in path of reclaim or
> > a dma fence.
> > 
> > v2:
> >   - s/arm/init (Christian)
> >   - Drop !array warn (Christian)
> > 
> > Cc: Sumit Semwal <sumit.semwal at linaro.org>
> > Cc: Christian König <christian.koenig at amd.com>
> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> 
> Reviewed-by: Christian König <christian.koenig at amd.com>

Thanks for the review.

Unfamilar with the merge flows to dma-buf subsystem. Do you merge this
into a dma-buf branch that we can then pick up in 6.12?

Matt

> 
> > ---
> >   drivers/dma-buf/dma-fence-array.c | 78 ++++++++++++++++++++++---------
> >   include/linux/dma-fence-array.h   |  6 +++
> >   2 files changed, 63 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c
> > index c74ac197d5fe..0659e6b29b3c 100644
> > --- a/drivers/dma-buf/dma-fence-array.c
> > +++ b/drivers/dma-buf/dma-fence-array.c
> > @@ -144,37 +144,38 @@ const struct dma_fence_ops dma_fence_array_ops = {
> >   EXPORT_SYMBOL(dma_fence_array_ops);
> >   /**
> > - * dma_fence_array_create - Create a custom fence array
> > + * dma_fence_array_alloc - Allocate a custom fence array
> > + * @num_fences:		[in]	number of fences to add in the array
> > + *
> > + * Return dma fence array on success, NULL on failure
> > + */
> > +struct dma_fence_array *dma_fence_array_alloc(int num_fences)
> > +{
> > +	struct dma_fence_array *array;
> > +
> > +	return kzalloc(struct_size(array, callbacks, num_fences), GFP_KERNEL);
> > +}
> > +EXPORT_SYMBOL(dma_fence_array_alloc);
> > +
> > +/**
> > + * dma_fence_array_init - Arm a custom fence array
> > + * @array:		[in]	dma fence array to arm
> >    * @num_fences:		[in]	number of fences to add in the array
> >    * @fences:		[in]	array containing the fences
> >    * @context:		[in]	fence context to use
> >    * @seqno:		[in]	sequence number to use
> >    * @signal_on_any:	[in]	signal on any fence in the array
> >    *
> > - * Allocate a dma_fence_array object and initialize the base fence with
> > - * dma_fence_init().
> > - * In case of error it returns NULL.
> > - *
> > - * The caller should allocate the fences array with num_fences size
> > - * and fill it with the fences it wants to add to the object. Ownership of this
> > - * array is taken and dma_fence_put() is used on each fence on release.
> > - *
> > - * If @signal_on_any is true the fence array signals if any fence in the array
> > - * signals, otherwise it signals when all fences in the array signal.
> > + * Implementation of @dma_fence_array_create without allocation. Useful to arm a
> > + * preallocated dma fence fence in the path of reclaim or dma fence signaling.
> >    */
> > -struct dma_fence_array *dma_fence_array_create(int num_fences,
> > -					       struct dma_fence **fences,
> > -					       u64 context, unsigned seqno,
> > -					       bool signal_on_any)
> > +void dma_fence_array_init(struct dma_fence_array *array,
> > +			  int num_fences, struct dma_fence **fences,
> > +			  u64 context, unsigned seqno,
> > +			  bool signal_on_any)
> >   {
> > -	struct dma_fence_array *array;
> > -
> >   	WARN_ON(!num_fences || !fences);
> > -	array = kzalloc(struct_size(array, callbacks, num_fences), GFP_KERNEL);
> > -	if (!array)
> > -		return NULL;
> > -
> >   	array->num_fences = num_fences;
> >   	spin_lock_init(&array->lock);
> > @@ -200,6 +201,41 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
> >   	 */
> >   	while (num_fences--)
> >   		WARN_ON(dma_fence_is_container(fences[num_fences]));
> > +}
> > +EXPORT_SYMBOL(dma_fence_array_init);
> > +
> > +/**
> > + * dma_fence_array_create - Create a custom fence array
> > + * @num_fences:		[in]	number of fences to add in the array
> > + * @fences:		[in]	array containing the fences
> > + * @context:		[in]	fence context to use
> > + * @seqno:		[in]	sequence number to use
> > + * @signal_on_any:	[in]	signal on any fence in the array
> > + *
> > + * Allocate a dma_fence_array object and initialize the base fence with
> > + * dma_fence_init().
> > + * In case of error it returns NULL.
> > + *
> > + * The caller should allocate the fences array with num_fences size
> > + * and fill it with the fences it wants to add to the object. Ownership of this
> > + * array is taken and dma_fence_put() is used on each fence on release.
> > + *
> > + * If @signal_on_any is true the fence array signals if any fence in the array
> > + * signals, otherwise it signals when all fences in the array signal.
> > + */
> > +struct dma_fence_array *dma_fence_array_create(int num_fences,
> > +					       struct dma_fence **fences,
> > +					       u64 context, unsigned seqno,
> > +					       bool signal_on_any)
> > +{
> > +	struct dma_fence_array *array;
> > +
> > +	array = dma_fence_array_alloc(num_fences);
> > +	if (!array)
> > +		return NULL;
> > +
> > +	dma_fence_array_init(array, num_fences, fences,
> > +			     context, seqno, signal_on_any);
> >   	return array;
> >   }
> > diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h
> > index 29c5650c1038..079b3dec0a16 100644
> > --- a/include/linux/dma-fence-array.h
> > +++ b/include/linux/dma-fence-array.h
> > @@ -79,6 +79,12 @@ to_dma_fence_array(struct dma_fence *fence)
> >   	for (index = 0, fence = dma_fence_array_first(head); fence;	\
> >   	     ++(index), fence = dma_fence_array_next(head, index))
> > +struct dma_fence_array *dma_fence_array_alloc(int num_fences);
> > +void dma_fence_array_init(struct dma_fence_array *array,
> > +			  int num_fences, struct dma_fence **fences,
> > +			  u64 context, unsigned seqno,
> > +			  bool signal_on_any);
> > +
> >   struct dma_fence_array *dma_fence_array_create(int num_fences,
> >   					       struct dma_fence **fences,
> >   					       u64 context, unsigned seqno,
>