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

[Matthew Brost <matthew.brost@intel.com>]

On Tue, Aug 27, 2024 at 04:10:31PM +0000, Matthew Brost wrote:
> On Tue, Aug 27, 2024 at 08:37:56AM +0200, Christian König wrote:
> > Am 26.08.24 um 21:23 schrieb 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@linaro.org>
> > > > > Cc: Christian König <christian.koenig@amd.com>
> > > > > Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> > > > Reviewed-by: Christian König <christian.koenig@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?
> > 
> > I can push the patches into drm-misc-next or alternatively you pick them up
> > through an XE branch.
> > 
> > The change to the dma_fence_array is small enough that it probably won't
> > cause any conflict, so both approaches works for me.
> > 
> 
> Once I have a review on patch number 2, I'll go ahead and merge to
> drm-xe-next. Will also reply here once that has happened.
> 

Merged to drm-xe-next.

Matt

> Matt
> 
> > Christian.
> > 
> > > 
> > > 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,
> >