[Intel-gfx] [PATCH 02/26] dma-buf: add dma_resv_for_each_fence

Christian König
2021-09-13T13:52:39Z

A simpler version of the iterator to be used when the dma_resv object is
locked.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
drivers/dma-buf/dma-resv.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/dma-resv.h | 18 ++++++++++++++++++
2 files changed, 56 insertions(+)

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index 213a9b7251ca..8cbccaae169d 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -323,6 +323,44 @@ void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
}
EXPORT_SYMBOL(dma_resv_add_excl_fence);

+/**
+ * dma_resv_walk - walk over fences in a dma_resv obj
+ * @obj: the dma_resv object
+ * @cursor: cursor to record the current position
+ * @all_fences: true returns also the shared fences
+ * @first: if we should start over
+ *
+ * Return all the fences in the dma_resv object while holding the
+ * dma_resv::lock.
+ */
+struct dma_fence *dma_resv_walk(struct dma_resv *obj,
+ struct dma_resv_cursor *cursor,
+ bool all_fences, bool first)
+{
+ dma_resv_assert_held(obj);
+
+ cursor->is_first = first;
+ if (first) {
+ struct dma_fence *fence;
+
+ cursor->index = -1;
+ cursor->fences = dma_resv_shared_list(obj);
+ cursor->is_exclusive = true;
+
+ fence = dma_resv_excl_fence(obj);
+ if (fence)
+ return fence;
+ }
+
+ if (!all_fences || !cursor->fences ||
+ ++cursor->index >= cursor->fences->shared_count)
+ return NULL;
+
+ return rcu_dereference_protected(cursor->fences->shared[cursor->index],
+ dma_resv_held(obj));
+}
+EXPORT_SYMBOL_GPL(dma_resv_walk);
+
/**
* dma_resv_walk_unlocked - walk over fences in a dma_resv obj
* @obj: the dma_resv object
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index f5b91c292ee0..6f9bb7e4c538 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -165,6 +165,21 @@ struct dma_resv_cursor {
bool is_exclusive;
};

+/**
+ * dma_resv_for_each_fence - fence iterator
+ * @obj: a dma_resv object pointer
+ * @cursor: a struct dma_resv_cursor pointer
+ * @all_fences: true if all fences should be returned
+ * @fence: the current fence
+ *
+ * Iterate over the fences in a struct dma_resv object while holding the
+ * dma_resv::lock. @all_fences controls if the shared fences are returned as
+ * well.
+ */
+#define dma_resv_for_each_fence(obj, cursor, all_fences, fence) \
+ for (fence = dma_resv_walk(obj, cursor, all_fences, true); fence; \
+ fence = dma_resv_walk(obj, cursor, all_fences, false))
+
/**
* dma_resv_for_each_fence_unlocked - fence iterator
* @obj: a dma_resv object pointer
@@ -399,6 +414,9 @@ void dma_resv_fini(struct dma_resv *obj);
int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence);
void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);
+struct dma_fence *dma_resv_walk(struct dma_resv *obj,
+ struct dma_resv_cursor *cursor,
+ bool first, bool all_fences);
struct dma_fence *dma_resv_walk_unlocked(struct dma_resv *obj,
struct dma_resv_cursor *cursor,
bool first, bool all_fences);
--
2.25.1