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path: root/drivers/dma-buf/reservation.c
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Diffstat (limited to 'drivers/dma-buf/reservation.c')
-rw-r--r--drivers/dma-buf/reservation.c156
1 files changed, 155 insertions, 1 deletions
diff --git a/drivers/dma-buf/reservation.c b/drivers/dma-buf/reservation.c
index a73fbf3b8e56..e6166723a9ae 100644
--- a/drivers/dma-buf/reservation.c
+++ b/drivers/dma-buf/reservation.c
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2012-2013 Canonical Ltd
+ * Copyright (C) 2012-2014 Canonical Ltd (Maarten Lankhorst)
*
* Based on bo.c which bears the following copyright notice,
* but is dual licensed:
@@ -37,3 +37,157 @@
DEFINE_WW_CLASS(reservation_ww_class);
EXPORT_SYMBOL(reservation_ww_class);
+
+/*
+ * Reserve space to add a shared fence to a reservation_object,
+ * must be called with obj->lock held.
+ */
+int reservation_object_reserve_shared(struct reservation_object *obj)
+{
+ struct reservation_object_list *fobj, *old;
+ u32 max;
+
+ old = reservation_object_get_list(obj);
+
+ if (old && old->shared_max) {
+ if (old->shared_count < old->shared_max) {
+ /* perform an in-place update */
+ kfree(obj->staged);
+ obj->staged = NULL;
+ return 0;
+ } else
+ max = old->shared_max * 2;
+ } else
+ max = 4;
+
+ /*
+ * resize obj->staged or allocate if it doesn't exist,
+ * noop if already correct size
+ */
+ fobj = krealloc(obj->staged, offsetof(typeof(*fobj), shared[max]),
+ GFP_KERNEL);
+ if (!fobj)
+ return -ENOMEM;
+
+ obj->staged = fobj;
+ fobj->shared_max = max;
+ return 0;
+}
+EXPORT_SYMBOL(reservation_object_reserve_shared);
+
+static void
+reservation_object_add_shared_inplace(struct reservation_object *obj,
+ struct reservation_object_list *fobj,
+ struct fence *fence)
+{
+ u32 i;
+
+ for (i = 0; i < fobj->shared_count; ++i) {
+ if (fobj->shared[i]->context == fence->context) {
+ struct fence *old_fence = fobj->shared[i];
+
+ fence_get(fence);
+
+ fobj->shared[i] = fence;
+
+ fence_put(old_fence);
+ return;
+ }
+ }
+
+ fence_get(fence);
+ fobj->shared[fobj->shared_count] = fence;
+ /*
+ * make the new fence visible before incrementing
+ * fobj->shared_count
+ */
+ smp_wmb();
+ fobj->shared_count++;
+}
+
+static void
+reservation_object_add_shared_replace(struct reservation_object *obj,
+ struct reservation_object_list *old,
+ struct reservation_object_list *fobj,
+ struct fence *fence)
+{
+ unsigned i;
+
+ fence_get(fence);
+
+ if (!old) {
+ fobj->shared[0] = fence;
+ fobj->shared_count = 1;
+ goto done;
+ }
+
+ /*
+ * no need to bump fence refcounts, rcu_read access
+ * requires the use of kref_get_unless_zero, and the
+ * references from the old struct are carried over to
+ * the new.
+ */
+ fobj->shared_count = old->shared_count;
+
+ for (i = 0; i < old->shared_count; ++i) {
+ if (fence && old->shared[i]->context == fence->context) {
+ fence_put(old->shared[i]);
+ fobj->shared[i] = fence;
+ fence = NULL;
+ } else
+ fobj->shared[i] = old->shared[i];
+ }
+ if (fence)
+ fobj->shared[fobj->shared_count++] = fence;
+
+done:
+ obj->fence = fobj;
+ kfree(old);
+}
+
+/*
+ * Add a fence to a shared slot, obj->lock must be held, and
+ * reservation_object_reserve_shared_fence has been called.
+ */
+void reservation_object_add_shared_fence(struct reservation_object *obj,
+ struct fence *fence)
+{
+ struct reservation_object_list *old, *fobj = obj->staged;
+
+ old = reservation_object_get_list(obj);
+ obj->staged = NULL;
+
+ if (!fobj) {
+ BUG_ON(old->shared_count == old->shared_max);
+ reservation_object_add_shared_inplace(obj, old, fence);
+ } else
+ reservation_object_add_shared_replace(obj, old, fobj, fence);
+}
+EXPORT_SYMBOL(reservation_object_add_shared_fence);
+
+void reservation_object_add_excl_fence(struct reservation_object *obj,
+ struct fence *fence)
+{
+ struct fence *old_fence = obj->fence_excl;
+ struct reservation_object_list *old;
+ u32 i = 0;
+
+ old = reservation_object_get_list(obj);
+ if (old) {
+ i = old->shared_count;
+ old->shared_count = 0;
+ }
+
+ if (fence)
+ fence_get(fence);
+
+ obj->fence_excl = fence;
+
+ /* inplace update, no shared fences */
+ while (i--)
+ fence_put(old->shared[i]);
+
+ if (old_fence)
+ fence_put(old_fence);
+}
+EXPORT_SYMBOL(reservation_object_add_excl_fence);