From: Christian König <christian.koenig@xxxxxxx>
Allows us to copy all the fences in a reservation object to another one.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/dma-buf/reservation.c | 58 +++++++++++++++++++++++++++++++++++++++++++
include/linux/reservation.h | 3 +++
2 files changed, 61 insertions(+)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
index 87f8f57..e2eff86 100644
--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -262,6 +262,64 @@ 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);
+
+ /*
+ * resize dst->fence or allocate if it doesn't exist,
+ * noop if already correct size
+ */
+ size = offsetof(typeof(*src_list), shared[src_list->shared_count]);
+ dst_list = kmalloc(size, GFP_KERNEL);
+ if (!dst_list)
+ return -ENOMEM;
+
+ kfree(dst->staged);
+ dst->staged = NULL;
+
+ 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]);
+
+ 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
* @obj: the reservation object
diff --git a/include/linux/reservation.h b/include/linux/reservation.h
index 156cfd3..21fc84d 100644
--- a/include/linux/reservation.h
+++ b/include/linux/reservation.h
@@ -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);
--
2.5.5
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