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Commit 7faf952a authored by Christian König's avatar Christian König Committed by Alex Deucher
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dma-buf: add reservation_object_copy_fences (v2) 



Allows us to copy all the fences in a reservation object to another one.

v2: handle NULL src_list

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1502384509-10465-2-git-send-email-alexander.deucher@amd.com
parent eac99d4a

drivers/dma-buf/reservation.c

+60 −0
Original line number Diff line number Diff line
@@ -261,6 +261,66 @@ void reservation_object_add_excl_fence(struct reservation_object *obj, 
}

EXPORT_SYMBOL(reservation_object_add_excl_fence);



/**

* reservation_object_copy_fences - Copy all fences from src to dst.

* @dst: the destination reservation object

* @src: the source reservation object

*

* Copy all fences from src to dst. Both src->lock as well as dst-lock must be

* held.

*/

int reservation_object_copy_fences(struct reservation_object *dst,

				   struct reservation_object *src)

{

	struct reservation_object_list *src_list, *dst_list;

	struct dma_fence *old, *new;

	size_t size;

	unsigned i;



	src_list = reservation_object_get_list(src);



	if (src_list) {

		size = offsetof(typeof(*src_list),

				shared[src_list->shared_count]);

		dst_list = kmalloc(size, GFP_KERNEL);

		if (!dst_list)

			return -ENOMEM;



		dst_list->shared_count = src_list->shared_count;

		dst_list->shared_max = src_list->shared_count;

		for (i = 0; i < src_list->shared_count; ++i)

			dst_list->shared[i] =

				dma_fence_get(src_list->shared[i]);

	} else {

		dst_list = NULL;

	}



	kfree(dst->staged);

	dst->staged = NULL;



	src_list = reservation_object_get_list(dst);



	old = reservation_object_get_excl(dst);

	new = reservation_object_get_excl(src);



	dma_fence_get(new);



	preempt_disable();

	write_seqcount_begin(&dst->seq);

	/* write_seqcount_begin provides the necessary memory barrier */

	RCU_INIT_POINTER(dst->fence_excl, new);

	RCU_INIT_POINTER(dst->fence, dst_list);

	write_seqcount_end(&dst->seq);

	preempt_enable();



	if (src_list)

		kfree_rcu(src_list, rcu);

	dma_fence_put(old);



	return 0;

}

EXPORT_SYMBOL(reservation_object_copy_fences);



/**

 * reservation_object_get_fences_rcu - Get an object's shared and exclusive

 * fences without update side lock held

include/linux/reservation.h

+3 −0
Original line number Diff line number Diff line
@@ -254,6 +254,9 @@ int reservation_object_get_fences_rcu(struct reservation_object *obj, 
				      unsigned *pshared_count,

				      struct dma_fence ***pshared);



int reservation_object_copy_fences(struct reservation_object *dst,

				   struct reservation_object *src);



long reservation_object_wait_timeout_rcu(struct reservation_object *obj,

					 bool wait_all, bool intr,

					 unsigned long timeout);