dma-buf/fence: add signal_on_any to the fence array v2

If @signal_on_any is true the fence array signals if any fence in the array
signals, otherwise it signals when all fences in the array signal.

v2: fix signaled test and add comment suggested by Chris Wilson.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-4-git-send-email-deathsimple@vodafone.de

2 files changed, 27 insertions, 9 deletions

diff --git a/drivers/dma-buf/fence-array.c b/drivers/dma-buf/fence-array.c
index 81412175a420..a8731c853da6 100644
--- a/drivers/dma-buf/fence-array.c
+++ b/drivers/dma-buf/fence-array.c
@@ -41,6 +41,7 @@ static void fence_array_cb_func(struct fence *f, struct fence_cb *cb)
 
         if (atomic_dec_and_test(&array->num_pending))
                 fence_signal(&array->base);
+        fence_put(&array->base);
 }
 
 static bool fence_array_enable_signaling(struct fence *fence)
@@ -51,10 +52,21 @@ static bool fence_array_enable_signaling(struct fence *fence)
 
         for (i = 0; i < array->num_fences; ++i) {
                 cb[i].array = array;
+                /*
+                 * As we may report that the fence is signaled before all
+                 * callbacks are complete, we need to take an additional
+                 * reference count on the array so that we do not free it too
+                 * early. The core fence handling will only hold the reference
+                 * until we signal the array as complete (but that is now
+                 * insufficient).
+                 */
+                fence_get(&array->base);
                 if (fence_add_callback(array->fences[i], &cb[i].cb,
-                                       fence_array_cb_func))
+                                       fence_array_cb_func)) {
+                        fence_put(&array->base);
                         if (atomic_dec_and_test(&array->num_pending))
                                 return false;
+                }
         }
 
         return true;
@@ -64,7 +76,7 @@ static bool fence_array_signaled(struct fence *fence)
 {
         struct fence_array *array = to_fence_array(fence);
 
-        return atomic_read(&array->num_pending) == 0;
+        return atomic_read(&array->num_pending) <= 0;
 }
 
 static void fence_array_release(struct fence *fence)
@@ -90,10 +102,11 @@ const struct fence_ops fence_array_ops = {
 
 /**
  * fence_array_create - Create a custom fence array
- * @num_fences: [in]    number of fences to add in the array
- * @fences:     [in]    array containing the fences
- * @context:    [in]    fence context to use
- * @seqno:      [in]    sequence number to use
+ * @num_fences:         [in]    number of fences to add in the array
+ * @fences:             [in]    array containing the fences
+ * @context:            [in]    fence context to use
+ * @seqno:              [in]    sequence number to use
+ * @signal_on_any       [in]    signal on any fence in the array
  *
  * Allocate a fence_array object and initialize the base fence with fence_init().
  * In case of error it returns NULL.
@@ -101,9 +114,13 @@ const struct fence_ops fence_array_ops = {
  * The caller should allocte the fences array with num_fences size
  * and fill it with the fences it wants to add to the object. Ownership of this
  * array is take and fence_put() is used on each fence on release.
+ *
+ * If @signal_on_any is true the fence array signals if any fence in the array
+ * signals, otherwise it signals when all fences in the array signal.
  */
 struct fence_array *fence_array_create(int num_fences, struct fence **fences,
-                                       u64 context, unsigned seqno)
+                                       u64 context, unsigned seqno,
+                                       bool signal_on_any)
 {
         struct fence_array *array;
         size_t size = sizeof(*array);
@@ -119,7 +136,7 @@ struct fence_array *fence_array_create(int num_fences, struct fence **fences,
                    context, seqno);
 
         array->num_fences = num_fences;
-        atomic_set(&array->num_pending, num_fences);
+        atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
         array->fences = fences;
 
         return array;
diff --git a/include/linux/fence-array.h b/include/linux/fence-array.h
index 593ab983129e..86baaa45567c 100644
--- a/include/linux/fence-array.h
+++ b/include/linux/fence-array.h
@@ -67,6 +67,7 @@ static inline struct fence_array *to_fence_array(struct fence *fence)
 }
 
 struct fence_array *fence_array_create(int num_fences, struct fence **fences,
-                                       u64 context, unsigned seqno);
+                                       u64 context, unsigned seqno,
+                                       bool signal_on_any);
 
 #endif /* __LINUX_FENCE_ARRAY_H */