On Wed, Jan 10, 2018 at 01:53:41PM +0100, Christian König wrote:
> Change reservation_object_get_fences_rcu to make the exclusive fence
> pointer optional.
>
> If not specified the exclusive fence is put into the fence array as
> well.
>
> This is helpful for a couple of cases where we need all fences in a
> single array.
>
> Signed-off-by: Christian König <christian.koe...@amd.com>
Seeing the use-case for this would be a lot more interesting ...
-Daniel
> ---
> drivers/dma-buf/reservation.c | 31 ++++++++++++++++++++++---------
> 1 file changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
> index b759a569b7b8..461afa9febd4 100644
> --- a/drivers/dma-buf/reservation.c
> +++ b/drivers/dma-buf/reservation.c
> @@ -374,8 +374,9 @@ EXPORT_SYMBOL(reservation_object_copy_fences);
> * @pshared: the array of shared fence ptrs returned (array is krealloc'd to
> * the required size, and must be freed by caller)
> *
> - * RETURNS
> - * Zero or -errno
> + * Retrieve all fences from the reservation object. If the pointer for the
> + * exclusive fence is not specified the fence is put into the array of the
> + * shared fences as well. Returns either zero or -ENOMEM.
> */
> int reservation_object_get_fences_rcu(struct reservation_object *obj,
> struct dma_fence **pfence_excl,
> @@ -389,8 +390,8 @@ int reservation_object_get_fences_rcu(struct
> reservation_object *obj,
>
> do {
> struct reservation_object_list *fobj;
> - unsigned seq;
> - unsigned int i;
> + unsigned int i, seq;
> + size_t sz = 0;
>
> shared_count = i = 0;
>
> @@ -402,9 +403,14 @@ int reservation_object_get_fences_rcu(struct
> reservation_object *obj,
> goto unlock;
>
> fobj = rcu_dereference(obj->fence);
> - if (fobj) {
> + if (fobj)
> + sz += sizeof(*shared) * fobj->shared_max;
> +
> + if (!pfence_excl && fence_excl)
> + sz += sizeof(*shared);
> +
> + if (sz) {
> struct dma_fence **nshared;
> - size_t sz = sizeof(*shared) * fobj->shared_max;
>
> nshared = krealloc(shared, sz,
> GFP_NOWAIT | __GFP_NOWARN);
> @@ -420,13 +426,19 @@ int reservation_object_get_fences_rcu(struct
> reservation_object *obj,
> break;
> }
> shared = nshared;
> - shared_count = fobj->shared_count;
> -
> + shared_count = fobj ? fobj->shared_count : 0;
> for (i = 0; i < shared_count; ++i) {
> shared[i] = rcu_dereference(fobj->shared[i]);
> if (!dma_fence_get_rcu(shared[i]))
> break;
> }
> +
> + if (!pfence_excl && fence_excl) {
> + shared[i] = fence_excl;
> + fence_excl = NULL;
> + ++i;
> + ++shared_count;
> + }
> }
>
> if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) {
> @@ -448,7 +460,8 @@ int reservation_object_get_fences_rcu(struct
> reservation_object *obj,
>
> *pshared_count = shared_count;
> *pshared = shared;
> - *pfence_excl = fence_excl;
> + if (pfence_excl)
> + *pfence_excl = fence_excl;
>
> return ret;
> }
> --
> 2.14.1
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
