Ping? David can you take a look?
Alex is on vacation and that is a rather important bug fix.
Thanks,
Christian.
Am 04.09.2017 um 21:02 schrieb Christian König:
From: Christian König <christian.koe...@amd.com>
Stop requiring that the src reservation object is locked for this operation.
Signed-off-by: Christian König <christian.koe...@amd.com>
---
drivers/dma-buf/reservation.c | 56 ++++++++++++++++++++++++++++++++-----------
1 file changed, 42 insertions(+), 14 deletions(-)
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
index dec3a81..b44d9d7 100644
--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -266,8 +266,7 @@ EXPORT_SYMBOL(reservation_object_add_excl_fence);
* @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.
+* Copy all fences from src to dst. dst-lock must be held.
*/
int reservation_object_copy_fences(struct reservation_object *dst,
struct reservation_object *src)
@@ -277,33 +276,62 @@ int reservation_object_copy_fences(struct
reservation_object *dst,
size_t size;
unsigned i;
- src_list = reservation_object_get_list(src);
+ rcu_read_lock();
+ src_list = rcu_dereference(src->fence);
+retry:
if (src_list) {
- size = offsetof(typeof(*src_list),
- shared[src_list->shared_count]);
+ unsigned shared_count = src_list->shared_count;
+
+ size = offsetof(typeof(*src_list), shared[shared_count]);
+ rcu_read_unlock();
+
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]);
+ rcu_read_lock();
+ src_list = rcu_dereference(src->fence);
+ if (!src_list || src_list->shared_count > shared_count) {
+ kfree(dst_list);
+ goto retry;
+ }
+
+ dst_list->shared_count = 0;
+ dst_list->shared_max = shared_count;
+ for (i = 0; i < src_list->shared_count; ++i) {
+ struct dma_fence *fence;
+
+ fence = rcu_dereference(src_list->shared[i]);
+ if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,
+ &fence->flags))
+ continue;
+
+ if (!dma_fence_get_rcu(fence)) {
+ kfree(dst_list);
+ src_list = rcu_dereference(src->fence);
+ goto retry;
+ }
+
+ if (dma_fence_is_signaled(fence)) {
+ dma_fence_put(fence);
+ continue;
+ }
+
+ dst_list->shared[dst_list->shared_count++] = fence;
+ }
} else {
dst_list = NULL;
}
+ new = dma_fence_get_rcu_safe(&src->fence_excl);
+ rcu_read_unlock();
+
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);
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